FIFTH SUPPLEMENTAL INDENTURE

Exhibit 4.2

NOBLE DRILLING CORPORATION,
as Issuer,

NOBLE DRILLING HOLDING LLC,
as Co-Issuer,

NOBLE DRILLING SERVICES 6 LLC,
as Co-Issuer,

NOBLE HOLDING (U.S.) CORPORATION,
as Guarantor,
and

NOBLE CORPORATION,
as Guarantor,
and

THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A.,
as Trustee

FIFTH SUPPLEMENTAL INDENTURE

Dated as of October 1, 2009

to

INDENTURE
Dated as of March 1, 1999, as previously amended and supplemented

7.50% SENIOR NOTES DUE 2019

          FIFTH SUPPLEMENTAL INDENTURE dated as of October 1, 2009, among NOBLE DRILLING CORPORATION, a corporation duly organized and existing under the laws of the State of Delaware (“ Noble Drilling ”), NOBLE DRILLING HOLDING LLC, a limited liability company duly organized and existing under the laws of the State of Delaware (“ Drilling Holding ,” and collectively with Noble Drilling, the “ Company ” or “ Companies ”), NOBLE DRILLING SERVICES 6 LLC, a limited liability company duly organized and existing under the laws of the State of Delaware (“ NDS6 ”), NOBLE HOLDING (U.S.) CORPORATION, a corporation duly organized and existing under the laws of the State of Delaware (“ Holding ”), and NOBLE CORPORATION, a Cayman Islands exempted company limited by shares (collectively with Holding, the “ Guarantors ”), and THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A., a national banking association, successor by merger to JPMorgan Chase Bank, National Association (formerly Chase Bank of Texas, National Association), as trustee (the “ Trustee ”).

R E C I T A L S:

          WHEREAS, Noble Drilling has previously executed and delivered to the Trustee an indenture dated as of March 1, 1999 (as supplemented by the First Supplemental Indenture thereto dated as of March 16, 1999, the Second Supplemental Indenture thereto dated as of April 30, 2002, the Third Supplemental Indenture thereto dated as of December 20, 2005 and the Fourth Supplemental Indenture thereto dated as of September 25, 2009, the “ Supplemented Indenture ”), providing for the issuance by Noble Drilling from time to time of its unsecured senior debt securities (the “ Securities ”), issuable in one or more series;

          WHEREAS, Noble Drilling has issued, and the Trustee has authenticated and delivered, a series of Securities designated “7.50% Senior Notes due 2019” (the “ Notes ”);

          WHEREAS, Noble Drilling Services 1 LLC, a limited liability company duly organized and existing under the laws of the State of Delaware (“ NDS1 ”) and successor to certain properties and assets of Noble Drilling, has assumed, by the Fourth Supplemental Indenture entered into on September 25, 2009, the due and punctual payment of the principal of, premium, if any, and interest on, and any Additional Amounts with respect to, the Securities and the performance of Noble Drilling’s covenants and obligations under the Supplemented Indenture and the Securities;

          WHEREAS, NDS1 and the Companies are the obligors with respect to the Notes and the Guarantors have guaranteed the due and punctual payment of the principal of, premium, if any, interest on, and all other amounts due under, the Notes;

          WHEREAS, as part of an internal reorganization, NDS1 and NDS6 intend to merge (the “ Merger ”), with NDS6 to be the surviving entity;

          WHEREAS, pursuant to Section 801 of the Supplemented Indenture, NDS6, as the successor by merger to NDS1, is required to expressly assume, by an indenture supplemental to the Supplemented Indenture, the due and punctual payment of the principal of, premium, if any, and interest on, and any Additional Amounts with respect to, the Securities and the

performance of Noble Drilling’s covenants and obligations under the Supplemented Indenture and the Securities;

          WHEREAS, Section 802 of the Supplemented Indenture provides that upon any merger by NDS1 into any other Person in accordance with Section 801, the successor Person into which NDS1 is merged shall succeed to, and be substituted for, and may exercise every right and power of, NDS1 under the Supplemented Indenture with the same effect as if such successor Person had been named as the Company in the Supplemented Indenture, and thereafter, NDS1 shall be relieved of all covenants and obligations under the Supplemented Indenture and the Securities;

          WHEREAS, Section 901 of the Supplemented Indenture provides that, without the consent of any Holders, NDS1, when authorized by a Board Resolution, and the Trustee, at any time and from time to time, may enter into one or more indentures supplemental to the Supplemented Indenture to evidence the succession of another Person to NDS1 and the assumption by any such successor of the covenants of NDS1 in the Supplemented Indenture and in the Securities;

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