COMMERCIAL PROMISSORY NOTE

Exhibit 10.2

COMMERCIAL PROMISSORY NOTE

Borrower’s Promise to Pay

For value received, the undersigned, ODYSSEY MARINE EXPLORATION, INC. , a Nevada corporation, authorized to do business in the State of Florida (the “Borrower”) promises to pay to the order of FIFTH THIRD BANK , a Michigan banking corporation (the “Lender”), the principal sum of TWO MILLION FIVE HUNDRED EIGHTY THOUSAND DOLLARS ($2,580,000.00), together with interest on the principal balance remaining unpaid from time to time at the rates set forth below.

1. Term . The term of this Note is from the date of this Note through July 11, 2013 (the “Maturity Date”).

2. Interest . Interest shall be paid on the principal outstanding from time to time at the Prime Rate plus three-quarters of one percent (.75%) per annum. The term “Prime Rate” is defined as the rate of interest published in the Wall Street Journal as the current “U.S. Prime Rate”. The rate of interest accruing hereunder shall be adjusted as and when any adjustment in the Prime Rate occurs. Borrower hereby acknowledges that the Prime Rate is not a rate of interest intended to be charged to any particular type of borrower. The Prime Rate is utilized by Lender to serve an administrative function in the setting of interest rates, and does not represent the best or lowest rate of interest available to any borrower or class of borrowers. Interest will be calculated on the basis of a 360-day year for actual number of days lapsed during the calculation period.

In the event the Wall Street Journal ceases or fails to publish a U.S. Prime Rate, regardless of the reason therefor, then the Lender may utilize the U.S. Prime Rate announced or published by any other nationally reputable financial institution for purposes of determining the interest rate for the remainder of the loan term. In the event that all nationally reputable financial institutions shall cease or fail to announce or publish a Prime Rate, regardless of the reason therefor, then the Lender may utilize the interest rate established by Lender in its sole discretion for purposes of determining the interest rate for the remainder of the loan term.

3. Payments . Principal payments in the amount of $10,750.00 plus accrued interest shall be due and payable monthly and shall be paid commencing August 11, 2008, and on the same day of each succeeding month thereafter through and including the Maturity Date. On the Maturity Date, the entire remaining principal indebtedness, plus all accrued and unpaid interest shall be due and payable in full.

All payments shall be made at: 201 E. Kennedy Boulevard, Suite 1800, Tampa, Florida 33602, or at such other place as may be designated in writing by the Lender.

Initials: MJH

4. Interest Rate Swap . At the mutual agreement of Borrower and Lender, Borrower may enter into one or more interest rate hedge agreements, interest rate swap agreements, interest rate caps or collars, or similar agreements with Lender, or an affiliate of Lender, in order to fix the interest payable hereunder.

5. Borrower’s Right to Prepay . This Note may be prepaid at any time without penalty.

6. Interest Limitation . Interest payable under this Note or any other payment which would be considered as interest or other charge for the use or loan of money shall never exceed the highest contract rate allowed by law applicable to this loan to be charged by Lender. If the interest or other charges collected or to be collected in connection with this loan exceed the permitted limits, then: (A) any such interest or loan charge shall be reduced by the amount necessary to reduce the charge to the permitted limit; and (B) any sums already collected from Borrower which exceeded permitted limits will be refunded. The Lender may choose to make this refund by reducing the principal owed under this Note or by making a direct payment to Borrower. If a refund reduces principal, the reduction will be treated as a partial prepayment.

7. Borrower’s Failure To Pay As Required .

(A) Late Charge for Overdue Payments . If the Lender has not received the full amount of any monthly payment by the end of ten (10) calendar days after it is due, Borrower will pay a late charge to the Lender equal to 5% of the overdue payment of principal and/ or interest. The payment or collection of any such late charge shall not constitute a waiver of any other right or remedy available to the Lender.

(B) Default . If Borrower fails to pay the full amount of each monthly payment by the end of the ten (10) calendar days after it is due, Bor