Kosmos Energy Ltd. (“Kosmos”) (NYSE: KOS) announced today the closing of the previously announced registered underwritten public offering of 30 million common shares, all of which were offered by existing shareholders and certain officers of Kosmos. The underwriters of the offering were granted an option, exercisable by March 16, 2013, to purchase up to an additional 4.5 million common shares from certain of the selling shareholders on the same terms and conditions to cover over-allotments, if any. Kosmos will not receive any of the proceeds from the sale of the common shares. Citigroup Global Markets Inc., Credit Suisse Securities (USA) LLC and Barclays Capital Inc. acted as joint book-running managers of the offering. The offering was made pursuant to an effective shelf registration statement, including a prospectus and a prospectus supplement relating to the offering, filed by Kosmos with the U.S. Securities and Exchange Commission (“SEC”). A copy of the prospectus and the prospectus supplement relating to the offering may be obtained for free by visiting the SEC website at www.sec.gov. This press release is for informational purposes only and does not constitute an offer to sell, or a solicitation of an offer to buy, nor shall there be any sale of these securities in any state or jurisdiction in which such an offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction. About Kosmos Energy Kosmos Energy is a leading independent oil and gas exploration and production company focused on frontier and emerging areas in Africa and South America. Forward-Looking Statements This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. All statements, other than statements of historical facts, included in this press release that address activities, events or developments that Kosmos expects, believes or anticipates will or may occur in the future are forward-looking statements. Kosmos’ estimates and forward-looking statements are mainly based on its current expectations and estimates of future events and trends, which affect or may affect its businesses and operations. Although Kosmos believes that these estimates and forward-looking statements are based upon reasonable assumptions, they are subject to several risks and uncertainties and are made in light of information currently available to Kosmos. When used in this press release, the words “anticipate,” “believe,” “intend,” “expect,” “plan,” “will” or other similar words are intended to identify forward-looking statements. Such statements are subject to a number of assumptions, risks and uncertainties, many of which are beyond the control of Kosmos, which may cause actual results to differ materially from those implied or expressed by the forward-looking statements. Further information on such assumptions, risks and uncertainties is available in Kosmos’ Securities and Exchange Commission (“SEC”) filings. Kosmos undertakes no obligation and does not intend to update or correct these forward-looking statements to reflect events or circumstances occurring after the date of this press release, except as required by applicable law. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release. All forward-looking statements are qualified in their entirety by this cautionary statement.