Rockhopper Regulatory News (RKH)

Embargoed: 0700hrs 21 November 2011

Rockhopper Exploration plc

("Rockhopper" or the "Company")

Well 14/10-9z: Completion of side track

Rockhopper Exploration plc (AIM: RKH), the North Falkland Basin oil and gas exploration company, is pleased to announce that coring operations at well 14/10-9z have been successfully completed.

The sidetrack, well 14/10-9z, was drilled to a total depth of 2600m md. A total 60m of core was cut through Casper and Sea Lion bringing the total amount of core cut during the entire drilling campaign to 340m (1,115 ft) to date.

Additionally, a further set of formation pressure test points and samples were taken over the Kermit reservoir which indicate residual oil saturation.

The well will now be plugged and abandoned as planned and a further announcement will be issued on the spudding of the next well, located in licence PL004b (which Rockhopper has farmed into with operatorship and an aggregate 60% interest), which will target the most southerly extent of the SLMC and additionally the Beverley prospect.

Enquiries:

Rockhopper Exploration plc

Sam Moody - Chief Executive

Tel. +44 (0)20 7920 2340 (via M: Communications)

M: Communications

Patrick d'Ancona or Ben Simons

Tel. +44 (0)20 7920 2340

Canaccord Genuity Limited

Charles Berkeley / Henry Fitzgerald-O'Connor

Tel. +44 (0) 20 7050 6500

Notes to Editors

Rockhopper was established in February 2004 with a strategy to invest in and carry out an offshore oil exploration programme to the north of the Falkland Islands. The Company floated on AIM in August 2005 and holds a 100 per cent. interest in four offshore production licences: PL023, PL024, PL032 and PL033 which cover approximately 3,800 sq. km. Rockhopper has also farmed in (7.5% working interest) to licences PL003 and PL004, which are operated by Desire Petroleum. In addition to the original farm-in, and in consideration for paying the full cost of the drilling of one well on the north-western acreage of licence PL004, known as Area 1, which Rockhopper believes contains the extension to the Sea Lion field and the western part of the "Beverley" prospect, Rockhopper has farmed-in with operatorship and an aggregate 60% interest in Area 1. Rockhopper has further farmed into the north-eastern part of licence PL004 known as Area 2, which the Company believes contains the "Jayne" prospect and the eastern part of the "Beverley" prospect, with an aggregate 25% interest. Rockhopper has now received the necessary regulatory approvals including consent for change of operatorship on licence PL004b (Area 1) which it now operates. These licences have been granted by the Falkland Islands government.

An extensive work programme has been carried out over a number of years on the licences operated by Rockhopper. This has included 2D and 3D Seismic and Controlled Source Electromagnetic Mapping (CSEM). In February 2010, the Ocean Guardian drilling rig arrived in Falkland waters to carry out a multi-well drilling campaign. Rockhopper drilled an exploration well on its Sea Lion prospect during April and May 2010, the result of which was the first oil discovery and Contingent Oil Resource in the North Falkland Basin. The Sea Lion discovery was successfully tested during September 2010 and June 2011 and was the first oil to flow to surface in Falkland Islands waters. Rockhopper contracted seismic vessels MV Polarcus Asima and Nadia to carry out a 3D seismic survey over areas of licences PL024, PL032 and PL033 which were not previously defined by 3D, as well as adjacent areas. Data over the southern portion of licences PL032 and PL033 has been fast track processed and an initial interpretation has now been completed. The balance of the newly acquired 3D seismic data is still being processed and the Company expects it will be available for interpretation before the end of 2011.

Rockhopper Exploration plc www.rockhopperexploration.co.uk