SLE.L Regulatory News (SLE)

20 December 2010

San Leon Energy Plc

Additional Listing

San Leon Energy Plc ("San Leon" or the "Company") is pleased to announce that application has been made for the admission to AIM of 13,967,440 new Ordinary Shares of Eur0.05 each in the Company ("Ordinary Shares"), as set out below.

Agreement with PGS

Further to the seismic services agreement entered into by San Leon with PGS Ventures AS ('PGS Ventures') announced on 18 September 2009, PGS exercised its right to subscribe for a further 11,441,487 new Ordinary Shares on 15 December 2010 at a price of 15 pence to partially fund a seismic survey acquired by the Company off the coast of Ireland (over its Slyne asset) during August 2010.

PGS Ventures has, furthermore, today informed the Company that, on 17 December 2010, it sold 11,441,487 Ordinary Shares. Following the issue of the 11,441,487 new Ordinary Shares resultant from the above subscription PGS is expected to have a resultant net unchanged position in the Company.

Agreement with Mazovia

On 15 November 2010 the Company announced that it had entered into a binding agreement to acquire three additional concessions for oil and gas reconnaissance and exploration from Mazovia Energy Resources Sp. z o.o. ("Mazovia") for USD1.0 million in cash and shares. 1,881,125 new Ordinary Shares the subject of the application are expected to be issued at GBP 0.2525, being the price at close of business on 14 December 2010, as settlement of monies due under the sale agreement.

As part of the agreement with Mazovia the new Ordinary Shares to be issued to Mazovia may not be sold for nine months from the date of the completion of the transaction, being 14 November 2010. Notwithstanding this agreement, Mazovia may sell such shares after six months provided that Mazovia (a) obtains San Leon's prior written consent; and (b) uses San Leon's broker for the sale.

Exercise of warrants

A further 644,828 new Ordinary Shares the subject of the application have arisen pursuant to the exercise of warrants to subscribe for Ordinary Shares.

Other matters

The new Ordinary Shares will rank pari passu with the Company's existing issued Ordinary Shares and dealings are expected to commence on 21 December 2010.

Following admission, the Company's enlarged issued share capital will comprise 450,682,278 Ordinary Shares, with voting rights. The Company does not hold any Ordinary Shares in treasury. Therefore the total number of Ordinary Shares in the Company with voting rights is 450,682,278, which figure may be used by shareholders in the Company as the denominator for the calculations by which they will determine if they are required to notify their interest in, or a change in their interest in, the share capital of the Company under the FSA's Disclosure and Transparency Rules.

For the purposes of the Company's conditional placing of 331,313,333 new Ordinary Shares, announced on 7 December 2010, if the resolutions are passed at the EGM to be held at 11.00 a.m. on 30 December 2010, the enlarged post-placing issued share capital of the company is now expected to be 781,995,611 Ordinary Shares, subject to any further ordinary course share issues prior to admission of the placing shares.

For further information contact:

San Leon Energy Plc Tel: + 353 1291 6292

Oisin Fanning, Chairman

Philip Thompson, Chief Executive Officer

www.sanleonenergy.com

Arbuthnot Securities Tel: +44 20 7012 2000

Nick Tulloch

Ben Wells

College Hill Tel: +44 20 7457 2020

Nick Elwes