Kosmos Energy Ltd. (“Kosmos”) (NYSE: KOS) announced today that it has commenced a registered underwritten public offering of approximately 30 million common shares, all of which will be offered by existing shareholders and certain officers of Kosmos. The underwriters of this offering have been granted an option, exercisable within 30 days, 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-allotment, 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. are acting as joint book-running managers of the offering. The offering is being made pursuant to an effective shelf registration statement, including a prospectus and a preliminary prospectus supplement relating to the offering, filed by Kosmos with the U.S. Securities and Exchange Commission (“SEC”). When available, copies of the prospectus and the preliminary prospectus supplement relating to the offering may be obtained for free by visiting the SEC website at www.sec.gov. Alternatively, copies of the prospectus and the preliminary prospectus supplement may be obtained from Citigroup, c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, New York 11717, telephone (800) 831-9146, email email@example.com, Credit Suisse Securities (USA) LLC, Attention: Prospectus Department, One Madison Avenue, New York, New York 10010, telephone (800) 221-1037, email firstname.lastname@example.org and Barclays Capital Inc., c/o Broadridge Financial Solutions, 1155 Long Island Ave, Edgewood, New York 11717, telephone (888) 603-5847, email email@example.com. 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. Any offer or sale of these securities will be made only by means of a prospectus, including a prospectus supplement, forming a part of the related registration statement.