Tullow Oil plc Share Offer on Ghana Stock Exchange at 31 Ghana Cedi per share

Tullow Oil plc (Tullow) today announces that it has opened its offer for 4,000,000 Tullow shares (Offer Shares) to be listed on the Ghana Stock Exchange (GSE) at an offer price of 31 Ghana Cedi per share and that the offer prospectus and application forms have been published. The offer price represents a 2.57% discount to the closing price of a Tullow share on the London Stock Exchange on 10 June 2011.

Offer Shares can be applied for between 13 June 2011 and 4 July 2011 in Ghana through Tullow’s sponsoring broker, IC Securities (Ghana) Limited. Offer Shares can also be applied for by visiting any branch of Standard Chartered Bank Ghana Limited or selected branches of Agricultural Development Bank in Ghana or the office of any of the authorised receiving agents. See www.tullowoil.com/ghana for more information. It is expected that admission of the Offer Shares to the GSE (GSE Admission) will take place on 27 July 2011.

The offer of Tullow shares on the GSE will give investors the opportunity to share in the future performance of Tullow’s operations in Ghana and more broadly across its global portfolio of assets. This listing and share offer further demonstrates Tullow’s long-term commitment to Ghana.

Any decision to invest in Offer Shares should only be made on the basis of information set out in the offer prospectus.

Further details about the offer

The Offer Shares represent approximately 0.45% of Tullow’s existing issued ordinary share capital.

The Offer Shares will, when issued, be credited as fully paid and will rank pari passu in all respects with Tullow’s existing ordinary shares of 10 pence each, including the right to receive all dividends and other distributions declared, made or paid on or in respect of such shares after the date of issue of the Offer Shares.

Tullow will apply for admission of the Offer Shares to listing on the Official List of the United Kingdom Listing Authority and to trading on the main market of the London Stock Exchange plc and trading on the Irish Stock Exchange (Admission). It is expected that Admission and GSE Admission will occur on the same date.

Tullow Group Overview

Tullow is a leading independent oil & gas, exploration and production group, quoted on the London and Irish Stock Exchanges (symbol: TLW) and is a constituent of the FTSE 100 Index. The Group has interests in over 90 exploration and production licences across 22 countries and focuses on four core areas: Africa, Europe, South Asia and South America.

In Africa, Tullow has production in Ghana, Gabon, Côte d’Ivoire, Mauritania, Congo (Brazzaville) and Equatorial Guinea with two large appraisal and development programmes in Ghana and Uganda. Tullow also has exploration interests in Gabon, Côte d’Ivoire, Liberia, Sierra Leone, Mauritania, Senegal, Tanzania, Madagascar, Namibia, Kenya and Ethiopia.

Tullow’s European interests are primarily focused on gas in the UK Southern North Sea where it has significant interests in the Caister-Murdoch System and the Thames area. The company also has interests offshore the Netherlands.

In South Asia, Tullow has exploration and production in Bangladesh and exploration interests in Pakistan. In South America, Tullow has exploration interests in Guyana, French Guiana and Suriname.

About Tullow Ghana

Tullow Oil plc, through its subsidiary, Tullow Ghana Limited, has interests in two exploration blocks in Ghana – Deepwater Tano and West Cape Three Points. Tullow is the operator of the Jubilee field, which straddles both blocks, and lies approximately 60 kilometres off the coast of Ghana. The Jubilee field was discovered in 2007 and First Oil was celebrated on 15 December 2010 following first initial production in November. Gross production has increased to over 70,000 bopd. Plateau production of 120,000 bopd is expected to be reached in July this year as the remaining four production wells are completed and brought on line. Jubilee is a world-class oil field with estimated recoverable resources of up to 1 billion barrels. In addition to Jubilee, Tullow has also discovered the Enyenra and Tweneboa fields which are currently being appraised and a comprehensive exploration programme is also ongoing.

Other information

This announcement is for information purposes only and shall not constitute an offer to buy, sell, issue, or subscribe for, or the solicitation of an offer to buy, sell, issue, or subscribe for any securities, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. This announcement has been issued by and is the sole responsibility of Tullow.

The distribution of this announcement, the offer prospectus and the offering of the Offer Shares in certain jurisdictions may be restricted by law. No action has been taken by Tullow that would permit an offering of such shares or possession or distribution of this announcement, the offer prospectus or any other offering or publicity material relating to such shares in any jurisdiction where action for that purpose is required. Persons into whose possession this announcement or the offer prospectus comes are required by Tullow to inform themselves about, and to observe such restrictions. Any failure to comply with any such restrictions may constitute a violation of the securities laws of any such jurisdiction.

The price of Tullow shares and the income from them may go down as well as up and investors may not get back the full amount invested on disposal of those shares.

Persons (including individuals, funds or otherwise) by whom or on whose behalf a commitment to acquire Offer Shares has been given (“Applicants”) will be deemed to have read and understood the offer prospectus, in its entirety and to be making such offer on the terms and conditions, and to be providing the representations, warranties, acknowledgements, and undertakings contained in the offer prospectus.

Neither this announcement or the offer prospectus is for distribution directly or indirectly in or into the United States (including its territories and possessions, any State of the United States and the District of Columbia), Canada, Australia or Japan or any jurisdiction into which the same would be unlawful. This announcement does not constitute or form part of an offer or solicitation to purchase or subscribe for shares in the capital of Tullow in the United States, Canada, Australia or Japan or any jurisdiction in which such an offer or solicitation is unlawful. In particular, the Offer Shares referred to in this announcement have not been, and will not be, registered under the Securities Act and may not be offered or sold in the United States absent registration or an exemption from the registration requirements under the Securities Act. The Offer Shares referred to in this announcement are being offered and sold outside the United States in accordance with Regulation S under the Securities Act and in the United States to ‘qualified institutional buyers’ in accordance with the exemption from registration under the Securities Act for transactions by an issuer not involving a public offering.

This announcement is not an offer of securities for sale in the United States. Securities may not be offered or sold in the United States absent registration under the Securities Act, or in accordance with an exemption from, or in a transaction not subject to, the registration requirements of the Securities Act. Tullow has not registered and does not intend to register any of the Offer Shares under the Securities Act. The Offer Shares will not be offered or sold to the public in the United States.

The relevant clearances have not been, and nor will they be, obtained from the securities commission of any province or territory of Canada; no prospectus has been lodged with, or registered by, the Australian Securities and Investments Commission or the Japanese Ministry of Finance; and the Offer Shares have not been, and nor will they be, registered under or offered in compliance with the securities laws of any state, province or territory of Canada, Australia or Japan. Accordingly, the Offer Shares may not (unless an exemption under the relevant securities laws is applicable) be offered, sold, resold or delivered, directly or indirectly, in or into the United States, Canada, Australia or Japan.

The Offer Shares have not been approved or disapproved by the U.S. Securities and Exchange Commission (the “SEC”), any State securities commission or any other regulatory authority in the United States, nor have any of the foregoing authorities passed upon or endorsed the merits of the share offer or the accuracy or adequacy of this announcement. Any representation to the contrary is unlawful. Persons (including, without limitation, nominees and trustees) who have a contractual or other legal obligation to forward a copy of this announcement or the offer prospectus should seek appropriate advice before taking any action.

Any dates stated are subject to change at the discretion of Tullow, subject to obtaining any necessary regulatory approvals. Any amendment will be published no later than 72 hours after receiving regulatory approval.

Neither the content of Tullow’s website nor any website accessible by hyperlinks on Tullow’s website is incorporated in, or forms part of, this announcement.