Rockhopper Regulatory News (RKH)

1 September 2015

Rockhopper Exploration plc

"Rockhopper" or the "Company"

Guendalina sidetrack commences

Rockhopper Exploration plc (AIM: RKH), the oil and gas exploration and production company with interests in the North Falkland Basin and the Greater Mediterranean and North Africa region, is pleased to announce that operations to drill a sidetrack well have begun at the Guendalina gas field (Eni Operator, Rockhopper 20% Working Interest). It is anticipated that operations will take approximately 80 days in total.

Sam Moody, CEO, commented:

"We are pleased to mark continued progress in building our Mediterranean business with the start of drilling operations at Guendalina. We anticipate a significant increase in revenue following the completion of the sidetrack."

For further information, please contact:

Rockhopper Exploration plc

Tel: (via Vigo Communications) - 020 7016 9570

Sam Moody - Chief Executive

Fiona MacAulay - Chief Operating Officer

Stewart MacDonald - Chief Financial Officer

Canaccord Genuity Limited (NOMAD and Joint Broker)

Tel: 020 7523 8000

Henry Fitzgerald-O'Connor

Liberum Capital (Joint Broker)

Tel: 020 3100 2227

Clayton Bush

Vigo Communications

Tel: 020 7016 9570

Peter Reilly

Patrick d'Ancona

Note regarding Rockhopper oil and gas disclosure

This announcement has been approved by Rockhopper's geological staff who include Fiona MacAulay (Chief Operating Officer), who is a Fellow of the Geological Society of London and a Member of the Petroleum Exploration Society of Great Britain and American Association of Petroleum Geologists with over 25 years of experience in petroleum exploration and management, and who is the qualified person as defined in the Guidance Note for Mining, Oil and Gas Companies issued by the London Stock Exchange in respect of AIM companies.