THIRD SUPPLEMENTAL INDENTURE

EXHIBIT 2.7

EXECUTION VERSION

THIRD SUPPLEMENTAL INDENTURE

THIRD SUPPLEMENTAL INDENTURE (this "Third Supplemental Indenture"), dated as of March 15, 2013 , among OCEAN RIG IRELAND OPERATIONS INC. (the "Guaranteeing Subsidiary"), a subsidiary of Drill Rigs Holdings Inc. (or its permitted successor), a Xxxxxxxx Islands corporation (the "Company"), the other Guarantors (as defined in the Indenture referred to herein), U.S. Bank National Association, as Trustee under the Indenture referred to below (the "Trustee"), and Deutsche Bank Trust Company Americas, as Noteholder Collateral Agent, Registrar and Paying Agent (as defined in the Indenture referred to herein).

W I T N E S S E T H

WHEREAS, the Company has heretofore executed and delivered to the Trustee an indenture, dated as of September 20, 2012, as amended by a supplemental indenture, dated as of January 23, 2013, and a second supplemental indenture, dated as of January 30, 2013 (the "Indenture"), providing for the issuance of 6.50% Senior Secured Notes due 2017 (the "Notes");

WHEREAS, the Indenture provides that under certain circumstances the Guaranteeing Subsidiary shall execute and deliver to the Trustee a supplemental indenture pursuant to which the Guaranteeing Subsidiary shall unconditionally guarantee all of the Company's Obligations under the Notes and the Indenture on the terms and conditions set forth herein (the "Note Guarantees"); and

WHEREAS, pursuant to Section 9.01 ("Without Consent of Holders") of the Indenture, the Trustee is authorized to execute and deliver this Third Supplemental Indenture.

NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the Guaranteeing Subsidiary and the Trustee mutually covenant and agree for the equal and ratable benefit of the Holders of the Notes as follows:

1.  Capitalized Terms.  Capitalized terms used herein without definition shall have the meanings assigned to them in the Indenture.

2.  Agreement To Guarantee.  The Guaranteeing Subsidiary hereby agrees to provide an unconditional Note Guarantee on the terms and subject to the conditions set forth in the Note Guarantee and in the Indenture, including but not limited to Article 11 thereof, and subject to the limitations therein.

3.  No Recourse Against Others.  No director, officer, employee, incorporator or stockholder of the Company or any Guarantor, as such, will have any liability for any obligations

of the Company or the Guarantors under the Notes, the Indenture or the Note Guarantees or for any claim based on, in respect of, or by reason of, such obligations or their creation.  Each Holder by accepting a Note waives and releases all such liability.  The waiver and release are part of the consideration for issuance of the Notes.  The waiver may not be effective to waive liabilities under the Federal securities laws.

4.  New York Law To Govern.  THE LAWS OF THE STATE OF NEW YORK SHALL GOVERN AND BE USED TO CONSTRUE THIS THIRD SUPPLEMENTAL INDENTURE.

5.  Counterparts.  The parties may sign any number of copies of this Third Supplemental Indenture.  Each signed copy shall be an original, but all of them together represent the same agreement.

6.  Effect of Headings.  The Section headings herein are for convenience only and shall not affect the construction hereof.

7.  The Trustee.  The Trustee shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Third Supplemental Indenture or for or in respect of the recitals contained herein, all of which recitals are made solely by the Guaranteeing Subsidiary and the Company.

IN WITNESS WHEREOF, the parties hereto have caused this Third Supplemental Indenture to be duly executed, all as of the date first above written.

Dated: March 15, 2013

OCEAN RIG IRELAND OPERATIONS INC.

by

/s/ Xxxx Xxxxxxx

Name:  Xxxx Xxxxxxx

Title:    Attorney-in-fact

DRILL RIG HOLDINGS INC., as the Company

by

/s/ Xxxx Xxxxxxx

Name:  Xxxx Xxxxxxx

Title:    Attorney-in-fact

OCEAN RIG UDW INC., as Parent and as a Guarantor

by

/s/ Xxxx Xxxxxxx

Name:  Xxxx Xxxxxxx

Title:    Attorney-in-fact

U.S. BANK NATIONAL ASSOCIATION, as Trustee

by

/s/ Xxxx X. Xxxxxxx

Name:  Xxxx X. Xxxxxxx

Title:    Vice President

DEUTSCHE BANK TRUST COMPANY AMERICAS, as Noteholder Collateral Agent, Registrar and Paying Agent

by: Deutsche Bank National Trust Company

by

/s/ Xxxxxxx Xxxxxxxxxx

Name:  Xxxxxxx Xxxxxxxxxx

Title:    Assistant Vice President

by

/s/ Xxxxx Xxxxxxxxxxxx

Name:  Xxxxx Xxxxxxxxxxxx

Title:    Vice President