UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

SCHEDULE 14A INFORMATION

PROXY STATEMENT PURSUANT TO SECTION 14 (a) OF THE SECURITIES

EXCHANGE ACT OF 1934 (Amendment No.     )

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o  Definitive proxy statement

þ  Definitive additional materials

o  Soliciting material pursuant to § 240.14a-12.

Diamond Offshore Drilling, Inc.

(Name of Registrant as Specified in its Charter)

(Name of Person (s) Filing Proxy Statement, if other than the Registrant)

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*** Exercise Your Right to Vote *** IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE STOCKHOLDER MEETING TO BE HELD ON MAY 23, 2011. Meeting Information DIAMOND OFFSHORE DRILLING, INC. Meeting Type: Annual Meeting For holders as of: March 28, 2011 Date: May 23, 2011 Time: 11:30 AM EDT Location: Regency Hotel 540 Park Avenue New York, New York 10021 You are receiving this communication because you hold shares in the above named company. DIAMOND OFFSHORE DRILLING, INC. This is not a ballot. You cannot use this notice to vote these shares. 15415 KATY FREEWAY This communication presents only an overview of the more complete HOUSTON, TX 77094 proxy materials that are available to you on the Internet. You may view the proxy materials online at www.proxyvote.com or easily request a paper copy (see reverse side). We encourage you to access and review all of the important information contained in the proxy materials before voting. This notice also constitutes Notice of the 2011 Annual Meeting of Stockholders. See the reverse side of this notice to obtain proxy materials and voting instructions.

Before You Vote How to Access the Proxy Materials Proxy Materials Available to VIEW or RECEIVE: 1. Annual Report 2. Notice & Proxy Statement How to View Online: Have the information that is printed in the box marked by the arrow JXXXX XXXX XXXX (located on the following page) and visit: www.proxyvote.com. How to Request and Receive a PAPER or E-MAIL Copy: If you want to receive a paper or e-mail copy of these documents, you must request one. There is NO charge for requesting a copy. Please choose one of the following methods to make your request: 1) BY INTERNET: www.proxyvote.com 2) BY TELEPHONE: 1-800-579-1639 3) BY E-MAIL*: sendmaterial@proxyvote.com * If requesting materials by e-mail, please send a blank e-mail with the information that is printed in the box marked by the arrow JXXXX XXXX XXXX (located on the following page) in the subject line. Requests, instructions and other inquiries sent to this e-mail address will NOT be forwarded to your investment advisor. Please make the request as instructed above on or before May 9, 2011 to facilitate timely delivery. How To Vote Please Choose One of the Following Voting Methods Vote In Person: Many stockholder meetings have attendance requirements including, but not limited to, the possession of an attendance ticket issued by the entity holding the meeting. Please check the meeting materials for any special requirements for meeting attendance. At the meeting, you will need to request a ballot to vote these shares. Vote By Internet: To vote now by Internet, go to www.proxyvote.com. Have the information that is printed in the box M34315-P06665 marked by the arrow JXXXX XXXX XXXX available and follow the instructions. Vote By Mail: You can vote by mail by requesting a paper copy of the materials, which will include a proxy card.

Voting Items The Board of Directors recommends you vote FOR Proposals 1, 2 and 3: 1. Election of Directors Nominees: 2. Ratify the appointment of Deloitte & Touche LLP as the independent auditors of the Company for 1a. James S. Tisch fiscal year 2011. 1b. Lawrence R. Dickerson 3. To approve, by non-binding vote, executive compensation. 1c. John R. Bolton The Board of Directors recommends you vote for 1 year: 1d. Charles L. Fabrikant 4. To recommend, by non-binding vote, the frequency of executive compensation votes. 1e. Paul G. Gaffney II NOTE: Such other business as may properly come before the meeting or any adjournment thereof. 1f. Edward Grebow 1g. Herbert C. Hofmann 1h. Andrew H. Tisch 1i. Raymond S. Troubh