Third Amendment to Credit Agreement among Hornbeck Offshore Services, LLC, Hornbeck Offshore Transportation, LLC, Hibernia National Bank, and Lenders

EXHIBIT 10.5

THIRD AMENDMENT TO CREDIT AGREEMENT

THIS THIRD AMENDMENT TO CREDIT AGREEMENT (this “Amendment”), dated September 30, 2003, is made among HORNBECK OFFSHORE SERVICES, LLC, a Delaware limited liability company (“HOS”); HORNBECK OFFSHORE TRANSPORTATION, LLC, a Delaware limited liability company formerly known as LEEVAC Marine, LLC (“HOT”; HOS and HOT are sometimes referred to herein collectively as the “Borrowers” and individually as a “Borrower”); HIBERNIA NATIONAL BANK, a national banking association, as agent (in such capacity, together with its successors and assigns in such capacity, the “Agent”); and the lenders listed on the signature pages hereof (the “Banks”), which agree as follows:

W I T N E S S E T H:

WHEREAS, Borrowers, Banks (other than DVB Bank Aktiengesellschaft) and Agent previously entered into that certain Credit Agreement dated as of December 31, 2001 (as previously amended by the First Amendment to Credit Agreement dated February 25, 2002, and the Second Amendment dated as of June 18, 2003, the “Original Credit Agreement”; the Original Credit Agreement, as amended hereby, is hereinafter referred to as the “Credit Agreement”) pursuant to which the Banks agreed to lend money to Borrowers upon and subject to the terms and conditions thereof;

WHEREAS, capitalized terms used herein without definition shall have the respective meanings given them in the Original Credit Agreement;

WHEREAS, Borrowers have requested that, among other things, (i) the Commitments and the Borrowing Base be increased from $50,000,000 to $60,000,000 in connection with the construction of three (3) new barges, and (ii) the limits on capital expenditures and investments in the Original Credit Agreement be amended to take into account those barges;

WHEREAS, the Banks (including DVB Bank Aktiengesellschaft) and the Agent are so willing, but only upon and subject to the terms and conditions hereof;

NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, Borrowers, Banks and Agent hereby agree as follows:

1. DVB Bank Aktiengesellschaft is hereby added as a Bank under the Credit Agreement. Its Credit Commitment and its Borrowing Base Credit Commitment both are $10,000,000. The Credit Commitments and the Borrowing Base Credit Commitments of the other Banks are not changing. Schedule 1 attached hereto reflects the foregoing and hereby amends and replaces Schedule 1 to the Original Credit Agreement (also taking into account the amendment to the definitions of Borrowing Base and Credit Limit in the Original Credit Agreement hereinafter provided for).

2. In addition to the amendment set forth in Section 1 above, the Original Credit Agreement is hereby amended as follows:

(a) Section 1.02 is hereby amended by deleting the definitions of Borrowing Base and Credit Limit set forth therein and substituting therefor the following new definitions of such terms:

“Borrowing Base” shall mean Sixty Million and No/100 ($60,000,000.00) Dollars. Any increase or decrease in the

Borrowing Base is subject to unanimous written approval of the Banks and, in addition, compliance, demonstrated to Agent’s satisfaction, by the Guarantor and the Borrowers with Section 5.17 and 5.18 hereof and applicable provisions of the Indenture (including without limitation, to the extent applicable, compliance with the Consolidated Interest Coverage Ratio test at Section 4.09 of the Indenture).

“Credit Limit” shall mean the lesser of (i) the Borrowing Base from time to time in effect, and (ii) Sixty Million and No/100 ($60,000,000.00) Dollars.

3. (i) In furtherance of the requirements set forth in Section 5 hereof and in accordance with the definition of HOS Vessels, the parties acknowledge and agree that the HOS BRIGADOON (O.N. 1077123) (the “Additional HOS Vessel”) is a HOS Vessel, and (ii) the Agent and the Required Banks hereby agree that the construction for HOT of the three (3) ocean-going double-hulled tank barges under Phase I of HOT’s OPA 90 New-Build Program, anticipated by HOT as of the date of this Amendment to have capacity of 135,000 barrels, 115,000 barrels and 50,000 barrels, shall not be counted under subsection 8.01(o) of the Credit Agreement as capital expenditures thereunder.

4. The Original Credit Agreement shall be deemed amended to the extent necessary to give effect to the foregoing. Except as amended hereby, the Original Credit Agreement shall remain in full force and effect.

5. As conditions precedent to the effectiveness of this Amendment, (i) all representations and warranties set forth in the Credit Agreement shall be true and correct as of the date hereof (other than those representations and warranties that are, by their specific items, limited in application to a specific date before the date of this Amendment), (ii) Borrowers shall have paid or caused to be paid all costs and expenses incurred by Agent and Banks, or otherwise agreed by Borrowers to be paid, through the date hereof, (iii) Borrowers shall have paid Agent an amendment fee in the amount of $15,000 for the account of all Banks other than DVB Bank Aktiengesellschaft ($5,000 per each such Bank) and a commitment fee in the amount of $25,000 for the account of DVB Bank Aktiengesellschaft, together with all other fees required to be paid through the date hereof, (iv) Borrowers shall have paid all interest on the Obligations accrued and unpaid through the day before this Amendment, and (v) Agent and Banks shall have received the following, all of which shall be in form and substance satisfactory to the Agent and in sufficient counterparts:

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6. Borrowers and, by their consent to this Amendment, Guarantor and HOS-IV specifically reaffirm, confirm and acknowledge the respective mortgages, pledges, assignments and security agreements and all other Loan Documents by each of them in favor of or with the Agent or the Banks, including without limitation the following:

To the extent any of such agreements represent security for the Obligations, whether now existing or hereafter arising, such security is hereby reaffirmed, confirmed and acknowledged by each Borrower and the Guarantor and HOS-IV, as applicable, and Obligations shall include, without limitation, the increased amount of the loans made or to be made as a result of the increase in the Credit Limit and the Borrowing Base put in place by virtue of this Amendment.

7. (a) Borrowers represent and warrant to Agent and Banks that no Default or Event of Default exists under the Credit Agreement.

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(b) Borrowers acknowledge and agree in favor of Agent and Banks that notwithstanding their representation and warranty set forth in the immediately preceding subsection (a), to the extent that there is any Default or Event of Default under the Credit Agreement, the execution and delivery (and acceptance) of this Amendment by Agent and Banks shall not constitute or be deemed to constitute in any respect a waiver of any such Default or Event of Default.

(c) Borrowers and, by their consent to this Amendment, Guarantor and HOS-IV acknowledge, agree, confirm, declare, represent and warrant to Agent and Banks that all of their respective representations and warranties set forth in the Credit Agreement and the other Loan Documents are true and correct on the date hereof (other than those representations and warranties that are, by their specific terms, limited in application to a specific date before the date of this Amendment), except that under Section 4.01 (and also in connection with Section 10.01 regarding notices) the Borrowers make reference to prior notice having been provided of the change of their chief executive office to 103 Northpark Blvd., Suite 300, Covington, Louisiana 70433. Without limiting the generality of the foregoing, Borrowers, Guarantor and HOS-IV represent and warrant to Agent and Banks that Borrowers, Guarantor and HOS-IV have reviewed the Indenture and are satisfied that each Borrower’s, Guarantor’s and HOS-IV’s execution, delivery and performance of this Amendment and the other documents provided in connection herewith will not violate any provision of the Indenture.

8. This Amendment shall be governed by and construed in accordance with the laws of the State of Louisiana.

9. This Amendment may be executed in one or more counterparts with the same effect as if the signatures hereto and thereto were upon the same instrument.

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IN WITNESS WHEREOF, Borrowers, Banks and Agent have executed and delivered this Amendment on the date first above written.

[Signatures continued on next page.]

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SCHEDULE 1

Commitments of the Banks