Press Release

HOUSTON, Jul 07, 2010 (BUSINESS WIRE) -- Diamond Offshore Drilling, Inc. (NYSE:DO) today announced the sale of the 350-ft. high-specification jack-up Ocean Shield to Ensco plc. Sale price of the rig is $186 million. The Shield is currently working under a term contract for Apache Corp. in Australia, which Ensco will assume.

Larry Dickerson, Diamond Offshore president and CEO, noted, "This opportunistic transaction involving a single rig will further augment our funds for potential investment in deepwater assets, such as last year's purchase of the Ocean Valor and OceanCourage." The Shield is a sister rig to the Ocean Scepter, which is contracted to OGX for a one-year term in Brazil. The Scepter is not for sale.

Diamond Offshore provides contract drilling services to the energy industry and is a leader in deepwater drilling. Additional information on Diamond Offshore and access to the Company's SEC filings is available on the Internet at http://www.diamondoffshore.com.

Statements contained in this press release which are not historical facts are "forward-looking statements" within the meaning of the federal securities laws. Forward-looking statements are inherently uncertain and subject to a variety of risks that could cause actual results to differ materially from those expected by management of the Company. A discussion of the important risk factors and other considerations that could materially impact these matters as well as the Company's overall business and financial performance can be found in the Company's reports filed with the Securities and Exchange Commission and readers of this release are urged to review those reports carefully when considering these forward-looking statements. Copies of these reports are available through the Company's website http://www.diamondoffshore.com. Given these risk factors, investors and analysts should not place undue reliance on forward-looking statements. Any such forward-looking statements speak only as of the date of this press release. The Company expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statement to reflect any change in the Company's expectations with regard thereto or any change in events, conditions or circumstances on which any forward-looking statement is based.

SOURCE: Diamond Offshore Drilling, Inc.

Diamond Offshore Drilling, Inc.
Director, Investor Relations
Les Van Dyke, 281-492-5370