Kazakhstan-Kul-Bas Exploration Period Extended

August 20, 2010

ASTANA, KAZAKHSTAN, Aug 20, 2010 (MARKETWIRE via COMTEX) —

Tethys Petroleum Limited (“Tethys” or the “Company”) (TSX: TPL) today announced that the Ministry of Oil and Gas of the Republic of Kazakhstan (“MOG”) has agreed to extend the Exploration Period for the Company’s Kul-Bas Exploration and Production Contract (the “Contract”) by a further two years until November 11, 2013. Suitable amendments will now be made to the Contract.

The Kul-Bas contract area (which currently covers an area of 7,632 km2 (1.9 million acres)) surrounds the Akkulka contract area where the Company has recently made the AKD01 “Doris” oil discovery and where work is currently underway to appraise this oil discovery and explore the surrounding area.

The original Contract terms involved a 6-year exploration period with relinquishments (after which all areas outside commercial discovery areas would be relinquished) and a 19 year production period, which could be extended. The extension to the exploration period gives Tethys an additional two years to explore this attractive area that has several prospects and leads and with a proved oil system in the Akkulka block which is surrounded by the Kul-Bas area.

George Mirtskhulava, Head of Tethys’ Kazakhstan Business Unit, commented: “I am very pleased that the Ministry of Oil and Gas continue to support Tethys’ exploration efforts in signing the Kul-Bas Exploration Contract Extension. This represents the second contract extension that Tethys has received this year (the first being the extension of the Akkulka Exploration Contract in June) and demonstrates the ongoing support which the Kazakh authorities show to oil and gas companies who meet their contractual commitments.”

Tethys is focused on oil and gas exploration and production activities in Central Asia with activities currently in the Republics of Kazakhstan, Tajikistan and Uzbekistan. This highly prolific oil and gas area is rapidly developing and Tethys believes that significant potential exists in both exploration and in discovered deposits.

This press release contains “forward-looking information” which may include, but is not limited to, statements with respect to our operations. Such forward-looking statements reflect our current views with respect to future events and are subject to certain risks, uncertainties and assumptions, including the risks relating to regulatory approvals and of sufficiency of the proceeds for the purposes contemplated. See the description of risks and uncertainties and underlying factors and assumptions relevant to the offering and “forward looking information” contained herein and to the Company’s business, including its exploration and development activities, contained in the Annual Information Form dated March 31, 2010 and other corporate filings (which are incorporated herein by reference). The “forward looking statements” contained herein speak only as of the date of this press release and, unless required by applicable law, the Company undertakes no obligation to publicly update or revise such information, whether as a result of new information, future events or otherwise.

Contacts: Tethys Petroleum Limited Sabin Rossi Vice President Investor Relations Office: +1 416 572 2065 +1 416 572 2201 (FAX) info@tethyspetroleum.com www.tethyspetroleum.com In Kazakhstan PG Communications Ardak Akanov, Managing Director Office phone/fax: +7 (727) 272 8867 +7 (727) 272 8237, +7 (727) 272 7745 development@pressclub.kz In Asia-Pacific Quam IR Anita Wan, Associate Director Office phone/fax: + (852) 2217-2999 anita.wan@quamgroup.com
SOURCE: Tethys Petroleum Limited

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