Testing Update

Island Oil and Gas PLC
16 June 2006


16 June 2006


                              ISLAND OIL & GAS PLC

                     Well 48/23-3 Testing Programme Update

Island Oil & Gas plc ('Island' or the 'Company') today announces that the
testing of Well 48/23-3 at Seven Heads West in the Celtic Sea is continuing. As
part of the testing programme, gas is currently being flared. Subject to
operational and weather conditions, Island will announce further details at the
conclusion of the testing programme in approximately one week.

The Well, which was spudded on 4 May 2006 in a water depth of 341 feet, was
drilled to its planned total depth of 3,237 feet TVD ss. The Well is operated by
Island, on behalf of the Company and its partners, Marathon Seven Heads Limited
and Sunningdale Oils Ireland Limited, and was drilled using the semi-submersible
drilling unit, Petrolia, owned and operated by Petrolia Drilling Limited under
contract to Island.


Enquiries:

Lisa J Newman MCIPR MIRS
Newman Consulting
Tel: [phone]


Notes to Editors:

Island was founded in 2003 and listed on AIM in December 2004. The Company has
interests in nine Irish offshore licences, (four as operator and two as
technical manager), including one producing gas field.

Island concluded a Sub-Area Equity Interest Assignment Agreement for the Seven
Heads West area with Marathon International Petroleum Hibernia Limited, through
its wholly-owned subsidiary Marathon Seven Heads Limited in February 2006. Under
the Agreement, Island is funding 100% of the cost of the current well, including
testing, in return for increasing its equity interest in the Seven Heads West,
Sub-Area, from 12.5% to 55.75%. Island has operated the well during the drilling
period but operatorship will revert back to Marathon once drilling and testing
has been completed.




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