As filed with the Securities and Exchange Commission on May 10, 2012October 17, 2018

Registration No.: 333-            333-227666

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

AMENDMENT NO. 1

TO

FORMFORM S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Odyssey Marine Exploration, Inc.

(Exact name of registrant as specified in its charter)

5215 West Laurel Street

Tampa, Florida 33607

(813)(813) 876-1776

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Gregory P. Stemm,Mark D. Gordon, Chief Executive Officer

5215 West Laurel Street

Tampa, Florida 33607

(813)(813) 876-1776

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

David M. Doney, Esq.

Akerman SenterfittLLP

401 East Jackson Street, Suite 1700

Tampa, Florida 33602

Telephone: (813)209-5070

Facsimile: (813)218-5404

Approximate date of commencement of proposed sale to the public: From time to time after the effective date of this registration statement.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.  ¨☐

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.  x☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ¨☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ¨☐

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box.  ¨☐

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box.  ¨☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, anon-accelerated filer, a smaller reporting company, or a small reportingan emerging growth company. See the definitiondefinitions of “large accelerated filer,” “accelerated filer,” and “small“smaller reporting company” and “emerging growth company” in Rule12b-2 of the Exchange Act (check one):

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of Securities Act.  ☐

CALCULATION OF REGISTRATION FEE

The information in this prospectus is not complete and may change. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and it is not soliciting an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

Subject to Completion — Dated May 10, 2012October 17, 2018

PROSPECTUS

8,658,295 Shares$100,000,000

Common Stock

Preferred Stock

Warrants

The selling stockholder listed in this prospectus under the section “Selling Stockholder” is offering:

This prospectus also covers any additional shares of common stock that may become issuable upon any anti-dilution adjustment pursuant to thespecific terms of the above-described warrantssecurities. You should read this prospectus and any prospectus supplements carefully before you invest. This prospectus may not be used to offer or sell any securities unless accompanied by reason of stock splits, stock dividends, or similar events. a prospectus supplement.

The senior convertible notes and the warrants to purchase common stock were acquired by the selling stockholder in a private placementsecurities may be sold directly by us that closed on November 10, 2011, and May 10, 2012.

The selling stockholder may sell all or a portion of the sharesto investors, through agents designated from time to time at prices which will be determined by the prevailing market price for the shares.or to or through underwriters or dealers. For additional information on the methods of sale, you should refer to the section entitled “Plan of Distribution.” We will not receiveIf any proceeds fromunderwriters are involved in the sale of any securities with respect to which this prospectus is being delivered, the common stock bynames of such underwriters and any applicable commissions or discounts will be set forth in a prospectus supplement. The net proceeds we expect to receive from such sale will also be set forth in a prospectus supplement.

Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page 2 of this prospectus. We may also include specific risk factors in an applicable prospectus supplement under the selling stockholder, except upon exerciseheading “Risk Factors.” You should review that section of the warrants to purchase common stock.prospectus supplement for a discussion of matters that investors in our securities should consider.

Our common stock is traded on the NASDAQ Capital Market under the symbol “OMEX.” On May 4, 2012,October 16, 2018, the closing price of our common stock on the NASDAQ Capital Market was $2.75$8.35 per share. As of October 16, 2018, the aggregate market value of our outstanding common stock held by non-affiliates, or the public float, was approximately $65.8 million, which was calculated based upon 7,880,216 shares of our outstanding common stock held by non-affiliates and a price of $8.35 per share, the closing price of our common stock on October 16, 2018. Pursuant to General Instruction I.B.6 ofForm S-3, in no event will we sell our common stock in a public primary offering with a value exceeding more thanone-third of our public float in any12-month period so long as our public float remains below $75.0 million. We have not offered any securities pursuant to General Instruction I.B.6 ofForm S-3 during the 12 calendar months prior to and including the date of this prospectus.

Investing in our common stock involves risks. See “Risk Factors” beginning on page 3 for a discussion of these risks.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is                     , 2012.2018.

Table of Contents

You should rely only on the information contained or incorporated by reference in this prospectus or any prospectus supplement. We have not authorized anyone to provide you with information that is different. We are not making an offer of securities in any state or jurisdiction where such an offer is not permitted. You should not assume that the information contained or incorporated by reference in this prospectus or any prospectus supplement is accurate as of any date other than the date on the front of such document.

i

About this Prospectus

This prospectus is a part of thea registration statement that we filed with the Securities and Exchange Commission. The selling stockholder namedCommission, or SEC, using a “shelf” registration process. Under the shelf registration process, we may sell common stock, preferred stock, and/or warrants in one or more offerings up to a total dollar amount of $100,000,000. This prospectus provides you with a general description of the securities we may offer. Each time we sell securities, we will provide a prospectus supplement that will contain more specific information. We may also add, update, or change in the prospectus supplement any of the information contained in this prospectus may from time to time sell the securities described in the prospectus. You should read thisThis prospectus, together with the more detailedapplicable prospectus supplements, includes all material information regarding our company, our common stock, and our financial statements and notesrelating to those statements that appear elsewhere inthis offering. You should carefully read both this prospectus and any applicable prospectus supplement together with the additional information that we incorporate in this prospectus by reference, which we describedescribed below under the heading “Documents Incorporated by Reference.”

“Where You should rely only on the information contained in this prospectus. We and the selling stockholder have not authorized any person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. We and the selling stockholder are not making an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus is accurate only as of the date on the front cover of this prospectus or other date stated in this prospectus. Our business, financial condition, results of operations, and prospects may have changed since that date.Can Find Additional Information.”

In this prospectus, we use the terms “Odyssey,” “our company,” “we,” “us,” and “our” to refer to Odyssey Marine Exploration, Inc. and its subsidiaries.

i

About Odyssey Marine Exploration

The Securities and Exchange Commission, or SEC, allows us to “incorporate by reference” certain information that we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus, and information that we file later with the SEC will update automatically, supplement, and/or supersede this information. Any statement contained in a document incorporated or deemed to be incorporated by reference in this prospectus shall be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in this prospectus or in any other document which also is or is deemed to be incorporated by reference in this prospectus modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus. You should read the following summary together with the more detailed information regarding our company, our common stock, and our financial statements and notes to those statements appearing elsewhere in this prospectus or incorporated herein by reference.

Odyssey Marine Exploration, Inc., or Odyssey, is engageda world leader in deep-ocean exploration. The discovery, development and extraction of deep-ocean minerals is our core focus. Our innovative techniques are also applied to shipwreck cargo recovery and other marine survey and exploration charter services. We have numerous projects in various stages of development around the world from both our own portfolio as well as through third-party contracts.

We have extensive experience discovering shipwreck sites in the archaeologically sensitive explorationdeep ocean and conducting archaeological excavations with remotely operated vehicles (“ROVs”). We have worked on some of the most historically important shipwreck projects to be discovered including the SS Republic, HMS Victory (1744), the SS Central America andLa Marquis de Tourny. Odyssey also has considerable experience conducting cargo recovery operations from 20th century shipwrecks in the deep ocean. Between 2012 and 2013, we recovered over 110 tons of silver cargo, representing 99% of the insured cargo, from the SS Gairsoppa, which was located nearly three miles deep. This was one of the largest and heaviest recoveries from a shipwreck in history. Odyssey is the exclusive provider of shipwreck search and recovery services for Magellan Offshore Services (“Magellan”). Odyssey also performs marine services for other customers, including private clients and governments.

In 2010, we began to leverage our core business expertise and technology for deep-ocean mineral exploration. Our expeditions conducted for Neptune Minerals, Inc. and Chatham Rock Phosphate, Ltd. resulted in the assessment of deep-water shipwrecks throughoutsignificant mineral deposits. We are also developing and exploring our own deep-ocean mineral projects. Through our majority stake in Oceanica Resources S. de. R.L., a Panamanian company, we control Exploraciones Oceanicas, S. de R.L. de C.V., which we call “ExO,” a Mexican company that has exclusive mining permits for an area known as the world. We employ advanced, state-of-the-art technology including side-scan sonar, remotely-operated vehicles, or ROVs,“Don Diego” deposit that contains large amounts of mineralized phosphate material. Our team performed all of theoff-shore exploration to find and other advanced technology that enables usvalidate the mineralized phosphate deposit and is managing the environmental studies and environmental permit application process with ExO. The phosphate deposit is one of the largest to locatebe identified and recover shipwrecks at depths that were previously unreachable in an economically feasible manner.is expected to be important to the regional and international fertilizer markets and is strategically important to Mexico and North America.

Our corporate offices are located at 5215 West Laurel Street, Tampa, Florida 33607. Our telephone number is (813)876-1776. Our Internet website address is www.shipwreck.net,www.odysseymarine.com, and all of our filings with the SEC are available free of charge on our website. Any information that is included on or linked to our Internet site is not a part of this prospectus.

Risk Factors

The prospectus supplement applicable to each type or series of securities we offer will contain a discussion of the risks applicable to an investment in Odyssey and to the particular types of securities that we are subjectoffering under that prospectus supplement. Prior to making a number of risks, whichdecision about investing in our securities, you should be aware of before you decide to buy our common stock. These risks arecarefully consider the specific factors discussed more fullyunder the caption “Risk Factors” in the applicable prospectus supplement, together with all of the other information contained or incorporated by reference in the prospectus supplement or appearing or incorporated by reference in this prospectus. You should also consider the risks, uncertainties, and assumptions discussed under the caption “Risk Factors” section ofincluded in our latest Annual Report on Form10-K and any subsequent Quarterly Reports on Form10-Q, which are incorporated by reference in this prospectus.prospectus, and which may be amended, supplemented, or superseded from time to time by other reports we file with the SEC in the future.

Special Note Regarding Forward-Looking Statements

This prospectus and the documents incorporatedany accompanying prospectus supplement includes and incorporates by reference into this prospectus contain forward-looking statements (within“forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended,or Securities Act, and Section 21E of the Securities Exchange Act of 1934, or Exchange Act, with respect to our financial condition, results of operations, plans, objectives, future performance, and business, which are usually identified by the use of words such as amended) that“will,” “may,” “anticipates,” “believes,” “estimates,” “expects,” “projects,” “plans,” “predicts,” “continues,” “intends,” “should,” “would,” or similar expressions. We intend for these forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995, and are including this statement for purposes of complying with these safe harbor provisions.

These forward-looking statements reflect our current views and expectations about our plans, strategies, and prospects, which are based on the information currently available and on current assumptions.

We cannot give any guarantee that these plans, intentions, or expectations estimates and projections about our industry, management’s beliefs, and assumptions made by management. Words such as “expect,” “anticipate,” “intend,” “plan,” “believe,” “seek,” “estimate,” other similar expressions, and the negative of such wordswill be achieved. Investors are intended to identifycautioned that all forward-looking statements but are not the exclusive means of identifying forward-looking statements in this prospectus. These statements are not guarantees of future performanceinvolve risks and are subject to certain risks, uncertainties, and assumptions that are difficult to predict; therefore, actual results may differ materially from those expressed or forecasteddiscussed in the forward-looking statements as a result of various factors, including those factors described under the heading “Risk Factors” and any risk factors contained in any forward-looking statements. The risks and uncertainties include, but are not limited to, those noted in “Risk Factors” belowprospectus supplement and in the documents incorporated by reference. We undertake no obligation to update publicly any forward-looking statements, whether as a result of new information, future events,reference herein or otherwise, except as otherwise required by law.

Description of Capital Stock

The following description of our capital stock, together with the additional information included in any applicable prospectus supplement, summarizes the material terms and provisions of these types of securities but is not complete. You should read our certificate of incorporation, as amended, our bylaws, as amended, and the certificate of designation relating to any particular series of preferred stock before you purchase any of our capital stock or securities convertible into shares of our capital stock because those documents, and not this description, set forth the terms of our capital stock.

We will describe in a prospectus supplement the specific terms of any capital stock we may offer pursuant to this prospectus. If indicated in a prospectus supplement, the terms of such capital stock may differ from the terms described below.

Authorized Capital Stock

Our authorized capitalization consists of 75,000,000 shares of common stock, par value $0.0001 per share, and 24,984,166 shares of preferred stock, par value $.0001 per share.

The authorized shares of common stock and preferred stock are available for issuance without further action by our stockholders, unless such action is required by applicable law or the rules of any stock exchange or automated quotation system on which our securities may be listed or traded. If the approval of our stockholders is not so required, our board of directors may determine not to seek stockholder approval.

Common Stock

As of September 30, 2018, we had 8,466,909 shares of common stock outstanding. The holders of our common stock are entitled to one vote per share on all matters to be voted upon by our shareholders. Subject to preferences that may be applicable to any outstanding shares of our preferred stock, the holders of common stock are entitled to receive ratably such dividends, if any, as may be declared from time to time by our board of directors out of funds legally available for that purpose. In the event of our liquidation, dissolution, or winding up, the holders of our common stock are entitled to share ratably in all assets remaining after payment of liabilities, subject to preferences applicable to shares of our preferred stock, if any, then outstanding. The common stock has no preemptive or conversion rights or other subscription rights. There are no redemption or sinking-fund provisions available to the common stock. All outstanding shares of our common stock are, and the shares of common stock offered by this prospectus are solely for the accountwill be, fully paid and nonassessable.

Preferred Stock

We have authority under our articles of the selling stockholder. We will not receive any proceeds from the sale of these shares. However, we will receive $5,625,000 if the warrantsincorporation to purchase common stock held by the selling stockholder are fully exercised for cash. We cannot guarantee that the selling stockholder will exercise the warrants. We expectissue up to use the net proceeds from any exercise of the warrants for general corporate purposes.

Private Placement of Notes and Warrants

The24,984,166 shares of commonour preferred stock, being offered by the selling stockholder are those issuable to the selling stockholder upon conversionpar value $.0001 per share. As of the notes and exerciseSeptember 30, 2018, there were no shares of the warrants that Odyssey issued to the selling stockholder pursuant to a securities purchase agreement between Odyssey and the selling stockholder. On November 9, 2011, Odysseyour preferred stock issued and sold a senior convertible note,outstanding.

Our board of directors, without further stockholder approval (except as may be required by applicable law or the rules of any stock exchange or automated quotation system on which we referour securities may be listed or traded) has the authority to as the initial note, in the original principal amount of $10.0 million and warrants to purchase up to 1,302,083issue shares of Odyssey’s common stock. On May 10, 2012, we issued a second senior convertible note, which we referpreferred stock in one or more series and to asfix the additional note, in the original principal amountrights, preferences, privileges, and restrictions thereof, including:

If our board of directors elects to exercise this authority, the rights and privileges of holders of shares of our common stock could be made subject to the rights and privileges of such series of preferred stock.

Although our board of directors has no intention at the present time of doing so, it could issue a series of preferred stock that could, depending on the terms of such series, impede the completion of a merger, tender offer, or other takeover attempt.

Nevada Laws

The Nevada Business Corporation Law contains a provision governing “Acquisition of Controlling Interest.” This law provides generally that any person or entity that acquires 20% or more of the outstanding voting shares of a publicly held Nevada corporation in the secondary public or private market may be denied voting rights with respect to the acquired shares, unless a majority of the disinterested stockholders of the corporation elects to restore such voting rights in whole or in part. The control share acquisition act provides that a person or entity acquires “control shares” whenever it acquires shares that, but for whichthe operation of the control share acquisition act, would bring its voting power within any of the following three ranges:

Market Information

Our common stock is traded on the NASDAQ Capital Market under the symbol “OMEX.”

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Computershare Trust Company, Inc., Golden, Colorado.

Description of Warrants

General

We may issue warrants for the purchase of common stock or preferred stock. Each series of warrants will be issued under a separate warrant agreement to be entered into between us and a bank or trust company, as warrant agent. The warrant agent will act solely as our agent in connection with the warrants. The warrant agent will not have any obligation or relationship of agency or trust for or with any holders or beneficial owners of the warrants. This summary of certain provisions of the warrants may be exercised increased to 1,562,500. In this prospectus, we sometimesis not complete. For the complete terms of a particular series of warrants, you should refer to the initial noteprospectus supplement and the additional note together as the “notes.”warrant agreement for that series of warrants.

Stock Warrants

The indebtedness evidenced by the initial note and the additional note bears interest at 8.0% and 9.0% per year, respectively, payable quarterly, and matures on the 30-month anniversaryprospectus supplement relating to a particular series of the initial closing date. The notes amortize in equal monthly installments commencing on the eight-month anniversary of the initial closing date. The initial note may be converted into Odyssey’swarrants to purchase our common stock at the option of the holder, at any time, and the additional note may be converted into Odyssey’s common stock, at the option of the holder, at any time following six months after the date of issuance. The initial conversion price of the notes was $3.74, subject to adjustment as provided in the notes. On May 10, 2012 (the six-month anniversary of the initial closing date), the conversion price applicable to the initial note was adjusted to $3.17, which represented the lesser of (a) the then-current conversion price and (b) the greater of (i) $1.44 and (ii) 110.0% of the market price of Odyssey’s common stock . On the earlier of (x) the date the registration statement registering the offer and sale of the common stock issuable under the notes and the warrants becomes effective and a prospectus contained therein shall be available for the resale by the holder of all of the registrable securities or (y) the six-month anniversary of the additional closing date, the conversion price of the additional note will be adjusted to the lesser of (a) the then-current conversion price and (b) the greater of (i) $1.00 and (ii) 110.0% of the market price of Odyssey’s common stock on the applicable date. The conversion price is also subject to adjustment for stock splits, stock dividends, recapitalizations, and similar transactions. Odyssey has agreed to pay each amortization payment in shares of Odyssey’s common stock, if certain conditions are met; provided, that Odyssey may, at its option, elect to pay such amortization payments in cash. The conversion rate applicable to any amortization payment in shares of Odyssey’s commonpreferred stock will be the lower of (a) the conversion price and (b) a price equal to 85.0% of the volume-weighted average price of Odyssey’s shares of common stock for a ten-day period immediately prior to the applicable amortization date. Subject to the satisfaction of certain conditions, at any time prior to November 10, 2012, Odyssey may redeem the additional note for an amount equal to 110% of the amount outstanding thereunder.

Underdescribe the terms of the warrants, including the holder is entitled to exercisefollowing:

Holders of equity warrants will not be entitled:

As set forth therein.

In accordance within the terms of a registration rights agreement withapplicable prospectus supplement, the holder of the notesexercise price and the warrants, this prospectus generally covers the resale of 120% of the sum of (a) the maximum number of shares of common stock issuableor preferred stock purchasable upon conversionexercise of a warrant will be subject to adjustment in certain events, including the notes, (b) the maximum numberissuance of other sharesa stock dividend to any holders of common stock, issuable pursuant to the notes and (c) the maximum number of sharesa stock split, reverse stock split, combination, subdivision or reclassification of common stock, issuable upon exercise of the warrants, in each case, determined asand such other events, if the outstanding notes and warrants were converted or exercised (as the case may be) in full (without regard to any, limitations on conversion or exercise contained therein) as of the trading day immediately preceding the date this registration statement was initially filed with the SEC. Because the conversion price of the notes and the exercise price of the warrants may be adjusted, the number of shares that will actually be issued may be more or less than the number of shares being offered by this prospectus. The fourth column assumes the sale of all of the shares offered by the selling stockholder pursuant to this prospectus.

Under the terms of the notes and the warrants, a selling stockholder may not convert the notes or exercise the warrants to the extent (but only to the extent) such selling stockholder or any of its affiliates would beneficially own a number of shares of our common stock which would exceed 4.99%. The number of sharesspecified in the second column reflects these limitations. The selling stockholder may sell all, some or none of its shares in this offering. See “Plan of Distribution.”applicable prospectus supplement.

Plan of Distribution

We are registering the shares of common stock issuable upon conversion of the notes and exercise of the warrants to permit the resale of these shares of common stock by the holder of the notes and warrants from time to time after the date of this prospectus. We will not receive any of the proceeds from the sale by the selling stockholder of the shares of common stock. We will bear all fees and expenses incident to our obligation to register the shares of common stock.

The selling stockholder may sell allthe securities separately or a portion of the shares of common stock held by it and offered hereby from time to time directly or together:

We may sell the sharessecurities from time to time in one or more transactions:

We will set forth in a prospectus supplement the terms of the offering of securities, including:

If we use underwriters for a sale of securities, the underwriters will acquire the securities for their own account. The underwriters may resell the securities in one or more transactions, including negotiated transactions, at a fixed prices, at prevailing market prices at the time of the sale,public offering price or at varying prices determined at the time of sale or at negotiated prices. These sales may be effected in transactions, which may involve crosses or block transactions, pursuant to one or moresale. The obligations of the following methods:

Underwriters, dealers, and agents may affect the marketability of the shares of common stock and the ability of any person or entity to engage in market-making activities with respect to the shares of common stock.

We will pay all expenses of the registration of the shares of common stock pursuant to the registration rights agreement, estimated to be $15,000.00 in total, including, without limitation, Securities and Exchange Commission filing fees and expenses of compliance with state securities or “blue sky” laws; provided, however, a selling stockholder will pay all underwriting discounts and selling commissions, if any. We will indemnify the selling stockholder against liabilities, including some liabilities under the Securities Act in accordance with the registration rights agreements or the selling stockholder will be entitled to contribution. We may be indemnifiedindemnification by the selling stockholderus against certain civil liabilities, including liabilities under the Securities Act, that may arise from any written information furnishedor to uscontribution with respect to payments made by the selling stockholder specificallyunderwriters, dealers, or agents, under agreements between us and the underwriters, dealers, and agents.

We may grant underwriters who participate in the distribution of securities an option to purchase additional securities to cover over-allotments, if any, in connection with the distribution.

Underwriters or agents and their associates may be customers of, engage in transactions with, or perform services for useus in this prospectus,the ordinary course of business.

Any underwriter may engage in over-allotment, stabilizing transactions, short covering transactions, and penalty bids in accordance with the related registration rights agreements or we may be entitled to contribution.

Once soldRegulation M under the registration statement,Exchange Act. Over-allotment involves sales in excess of the offering size, which this prospectus formscreate a part,short position. Stabilizing transactions permit bids to purchase the sharesunderlying security so long as the stabilizing bids do not exceed a specified maximum. Short covering transactions involve purchases of common stock will be freely tradablethe securities in the handsopen market after the distribution is completed to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a covering transaction to cover short positions. Those activities may cause the price of persons otherthe securities to be higher than our affiliates.it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time.

Any underwriters who are qualified market makers on the NASDAQ Stock Market may engage in passive market-making transactions in the securities on the NASDAQ Stock Market in accordance with Rule 103 of Regulation M, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the securities. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded.

Legal Matters

The validity of the issuance of the common stocksecurities offered by this prospectus will be passed upon by Akerman Senterfitt, counsel to Odyssey Marine Exploration, Inc.LLP, Tampa, Florida.

Experts

The consolidated financial statements of Odyssey and its subsidiaries as of December 31, 20112015, 2016, and 2010, and for each of the years in the three-year period ended December 31, 2011, are2017, incorporated in this prospectus by reference from our Annual Report on Form10-K for the year ended December 31, 2011,2017, have been audited by Ferlita, Walsh, Gonzalez & Gonzalez,Rodriguez, P.A., independent registered public accounting firm, as stated in their report which is incorporated herein by reference and has been so incorporated in reliance upon the report of such firm given upon their authority as experts in accounting and auditing.

Documents Incorporated by ReferenceWhere You Can Find Additional Information

We furnish our stockholdershave filed a registration statement on FormS-3 with annualthe SEC relating to the common stock, the preferred stock, and the warrants offered by this prospectus. This prospectus does not contain all of the information set forth in the registration statement and the exhibits and schedules thereto. We have omitted parts of the registration statement, as permitted by the rules and regulations of the SEC. Statements contained in this

prospectus as to the contents of any contract or other document referred to are not necessarily complete and in each instance reference is made to the copy of such contract or other document filed as an exhibit to the registration statement, each such statement being qualified in all respects by such reference. For further information with respect to us and the common stock, the preferred stock, and the warrants offered hereby, reference is made to such registration statement, exhibits, and schedules.

We are subject to the information and periodic reporting requirements of the Exchange Act, and, in accordance therewith, file periodic reports, containing audited financial statements and other appropriate reports. We also file annual, quarterly, and current reports, proxy statements, and other information with the SEC. InsteadSuch periodic reports, current reports, proxy statements, other information, and a copy of repeatingthe registration statement on FormS-3 may be inspected by anyone without charge and copies of these materials may be obtained upon the payment of the fees prescribed by the SEC, at the Public Reference Room maintained by the SEC at 100 F Street, N.E., Washington, D.C. 20549. The public may obtain information on the operation of the Public Reference Room by calling the SEC at1-800-SEC-0330. The registration statement on FormS-3 and the periodic reports, current reports, proxy statements, and other information filed by us are also available through the Internet web site maintained by the SEC at the following address: http://www.sec.gov.

(Remainder of page intentionally left blank.)

Documents Incorporated by Reference

The SEC allows us to “incorporate by reference” into this prospectus the information we file with it. This means that we have alreadycan disclose important information to you by referring you to those documents. The information we incorporate by reference is considered to be a part of this prospectus, and later information we file with the SEC will automatically update and supersede this information. The following documents filed with the SEC we(in each case, Commission FileNo. 001-31895) are allowed to “incorporate by reference” in this prospectus information contained in those documents we have filed with the SEC. These documents are considered to be part of this prospectus.

We incorporateincorporated by reference in this prospectus the documents listed below and any future filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act until the selling stockholder sell all of the shares of common stock offered by this prospectus:

Any documents thatWe are also incorporating by reference any future filings we filemake with the SEC pursuant tounder Section 13(a), 13(c), 14, or 15(d) of the Exchange Act prioruntil this offering is completed, including those made between the date of filing of the initial registration statement and to the selling stockholder selling alldate of effectiveness of the shares of common stock offered by this prospectus will also be considered to be part of this prospectus and will automatically update and supersede theregistration statement, except for information contained in this prospectus.

Current Reports on Form 8-K containing only Regulation FD or Regulation G disclosure furnished under Item 2.02 or Item 7.01 of our Current Reports on Form8-K, (or the analogous Items of the predecessor Form 8-K) are which is not deemed to be filed and not incorporated herein by reference.reference herein.

At your verbal or written request, we will provide you, without charge, a copy of any of the documents we have incorporated by reference into this prospectus but not delivered with the prospectus (other than exhibits to such documents, unless those exhibits are specifically incorporated by reference into the documents that this prospectus incorporates). If you want more information, write or call:

Michael J. Holmes,Jay A. Nudi, Chief Financial Officer

Odyssey Marine Exploration, Inc.

5215 West Laurel Street

Tampa, Florida 33607

(813)876-1776

Where You Can Find More Information

This prospectus is being delivered to you in accordance with the U.S. securities laws. We have filed a registration statement with the SEC to register the common stock that the selling stockholder are offering to you. This prospectus is part of that registration statement. As allowed by the SEC’s rules, this prospectus does not contain all of the information that is included in the registration statement.

You may obtain a copy of the registration statement, or a copy of any other filing we have made with the SEC, directly from the SEC. You may either:

You may obtain more information on the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330.

8,658,295 Shares

$100,000,000

Common Stock

Preferred Stock

Warrants

PART II

INFORMATION NOT REQUIRED IN THE PROSPECTUS

Item 14.Other Expenses of Issuance and Distribution.

The following table sets forth the costs and expenses, other than underwriting discounts and commissions, payable by the registrant in connection with the sale and distribution of the common stocksecurities being registered. Selling commissions and brokerage fees and any applicable transfer taxes and fees and disbursements of counsel for the selling stockholder are payable individually by each of the selling stockholder.registered hereunder. All amounts shown are estimates except the SEC registration fee.

Item 15.Indemnification of Directors and Officers.

Article VII of Odyssey’s Articles of Incorporation provides that Odyssey is authorized to indemnify directors, officers, employees, and agents to the full extent allowed for under the Nevada Business Corporation Act.

Article XI of Odyssey’s Articles of Incorporation provides that no director, officer or stockholder of Odyssey shall be personally liable for damages for breach of fiduciary duty as a director or officer; provided, that this provision shall not eliminate liability of a director or officer for acts or omissions involving intentional misconduct, fraud, or a knowing violation of law or payments or distributions in violation of Nevada law.

Nevada Revised Statutes Section 78.138 currently provides that a director or officer will not be individually liable to the corporation, its stockholders, or its creditors unless it is proven that (a) the director’s or officer’s act or failure to act constituted a breach of his or her fiduciary duties as a director or officer and (b) such breach involved intentional misconduct, fraud or a knowing violation of the law. To the extent that Article XI of our articles of incorporation would be deemed to be inconsistent with Section 78.138, the provisions of such statute should control.

Additionally, Nevada Revised Statutes Sections 78.7502 and 78.751 permit us to indemnify our directors and officers as follows:

1. A corporation may indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative, except an action by or in the right of the corporation, by reason of the fact that he is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise, against expenses, including attorneys’ fees, judgments, fines and amounts paid in settlement actually and reasonably incurred by him in connection with the action, suit or proceeding if he (a) is not liable pursuant to Section 78.138 of the Nevada Revised Statutes or (b) acted in good faith and in a manner which he reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding, had no reasonable cause to believe his conduct was unlawful. The termination of any action, suit or proceeding by judgment, order,

II-1

settlement, conviction, or upon a plea of nolo contendere or its equivalent, does not, of itself, create a presumption that the person is liable pursuant to Section 78.138 or did not act in good faith and in a manner which he reasonably believed to be in or not opposed to the best interests of the

II-1

corporation, or that, with respect to any criminal action or proceeding, he had reasonable cause to believe that his conduct was unlawful.

2. A corporation may indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action or suit by or in the right of the corporation to procure a judgment in its favor by reason of the fact that he is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise against expenses, including amounts paid in settlement and attorneys’ fees actually and reasonably incurred by him in connection with the defense or settlement of the action or suit if he (a) is not liable pursuant to 78.138 of the Nevada Revised Statutes or (b) acted in good faith and in a manner which he reasonably believed to be in or not opposed to the best interests of the corporation. Indemnification may not be made for any claim, issue or matter as to which such a person has been adjudged by a court of competent jurisdiction, after exhaustion of all appeals therefrom, to be liable to the corporation or for amounts paid in settlement to the corporation, unless and only to the extent that the court in which the action or suit was brought or other court of competent jurisdiction determines, upon application, that in view of all the circumstances of the case, the person is fairly and reasonably entitled to indemnity for such expenses as the court deems proper.

3. To the extent that a director, officer, employee or agent of a corporation has been successful on the merits or otherwise in defense of any action, suit or proceeding referred to in subsections 1 and 2 above, or in defense of any claim, issue or matter herein, he must be indemnified by the corporation against expenses, including attorneys’ fees, actually and reasonably incurred by him in connection with the defense.

4. Any discretionary indemnification under subsections 1 and 2 above, unless ordered by a court or advanced pursuant to subsection 5 below, may be made by the corporation only as authorized in the specific case upon a determination that indemnification of the director, officer, employee or agent is proper in the circumstances. The determination must be made:

5. The articles of incorporation, the bylaws or an agreement made by the corporation may provide that the expenses of officers and directors incurred in defending a civil or criminal action, suit or proceeding must be paid by the corporation as they are incurred and in advance of the final disposition of the action, suit or proceeding, upon receipt of an undertaking by or on behalf of the director or officer to repay the amount if it is ultimately determined by a court of competent jurisdiction that he is not entitled to be indemnified by the corporation. The provisions of this subsection do not affect any rights to advancement of expenses to which corporate personnel other than directors or officers may be entitled under any contract or otherwise by law.

II-2

6. The indemnification and advancement of expenses authorized in or ordered by a court pursuant to Nevada Revised Statutes Section 78.7502 and Section 78.751:

II-2

We may also purchase and maintain insurance on behalf of our directors, officers, employees, and agents for any liability asserted against such persons and liability or expenses incurred by such persons in their capacity as a director, officer, employee, or agent, or arising out of status as such, whether or not the company has the authority to indemnify such persons against such liability and expenses.

Item 16.Exhibits.

The exhibits to this registration statement are listed in the Index to Exhibits on PageE-1 of this registration statement, which Index to Exhibits is incorporated herein by reference.

Item 17.Undertakings.

(a)

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

II-3

provided, however, that paragraphs (a)(1)(i), (a)(1)(ii), and (a)(1)(iii) do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the registrant pursuant to section 13 or section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

(2) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initialbona fide offering thereof.

(3) To remove from registration, by means of a post-effective amendment, any of the securities being registered which remain unsold at the termination of the offering.

(4) That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser, if the registrant is subject to Rule 430C, each prospectus filed pursuant to Rule 424(b) as part of a registration

II-3

statement relating to an offering, other than registration statements relying on Rule 430B or other than prospectuses filed in reliance on Rule 430A, shall be deemed to be part of and included in the registration statement as of the date it is first used after effectiveness;provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such first use, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such date of first use.

(5) That, for the purpose of determining liability of the registrant under the Securities Act of 1933 to any purchaser in the initial distribution of the securities:

The undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i) Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424 (§230.424 of this chapter);

(ii) Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;

(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and

(iv) Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

(b) The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual report pursuant to section 13(a) or section 15(d) of the Securities Exchange Act of 1934(and,1934 (and, where applicable, each filing of an employee benefits plan annual report pursuant to section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in this Registration Statement shall be deemed to be a new registration statement relating to the securities offered herein, and the offering of such securities at that time shall be deemed to be the initialbona fideoffering thereof.

(c) Insofar as indemnification for liabilities arising under the 1933 Act may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Commission such indemnification is against public policy as expressed in the 1933 Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the 1933 Act and will be governed by the final adjudication of such issue.

(d) The undersigned registrant hereby undertakes to deliver or cause to be delivered with the prospectus, to each person to whom the prospectus is sent or given, the latest annual report, to security holders that is incorporated by reference in the prospectus and furnished pursuant to and meeting the requirements ofRule 14a-3 or Rule14c-3 under the Securities Exchange Act of 1934; and, where interim financial information required to be presented by Article 3 of RegulationS-X is not set forth in the prospectus, to deliver, or cause to be delivered to each person to whom the prospectus is sent or given, the latest quarterly report that is specifically incorporated by reference in the prospectus to provide such interim financial information.

II-4

(e) Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such issue.

II-5

INDEX TO EXHIBITS

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on FormS-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Tampa, State of Florida, on May 10, 2012.October 17, 2018.

POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that each of the directors and/or executive officers of Odyssey Marine Exploration, Inc. whose signature appears below hereby appoints Gregory P. Stemm and Michael J. Holmes, and each of them severally, as his attorney-in-fact to sign in his name and on his behalf, in any and all capacities stated below and to file with the Securities and Exchange Commission, any and all amendments, including post-effective amendments to this registration statement, making such changes in the registration statement as appropriate, and any registration statement filed pursuant to Rule 462(b) of the Act prepared in connection therewith, and generally to do all such things in their behalf in their capacities as officers and directors to enable Odyssey Marine Exploration, Inc. to comply with the provisions of the Securities Act of 1933, and all requirements of the Securities and Exchange Commission.

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed by the following persons in the capacities and on the dates indicated.

II-5

INDEX TO EXHIBITS

E-1II-7