ENQUEST PLC, 19 August 2015.  Results for the 6 months ended 30 June 2015*

Strong production growth of 17%, to 29,665 Boepd
Highlights

  · Production averaged 29,665 Boepd, up 17.3%, on H1 2014, reflecting a strong
operational performance and continued high levels of production efficiency.
EnQuest’s Malaysian assets contributed 7,777 Boepd.

  · 2015 full year guidance is maintained at an average of between 33,000 Boepd
and 36,000 Boepd, including first production from Alma/Galia.

  · Revenue of $444.0 million and EBITDA** of $226.7 million reflected the
decline in the oil price, partially offset by the positive impact of the hedging
programme.

  · Alma/Galia: Commissioning of subsea and topside systems is largely complete,
with first oil expected within a few weeks.

  · Kraken: The project continues to be on budget and on schedule for first oil
in 2017. Batch drilling of the top-holes at the first drill centre has been
completed. The Floating Production, Storage and Offloading vessel (‘FPSO’)
continues to be on track for delivery in 2016.

  · The programme of cost reduction initiatives continues and is on track for
unit opex of an average of c.$38/bbl in 2015, and average unit opex in the low
$30s/bbl is now anticipated in 2016.

* Unless otherwise stated, all figures are before exceptional items and
depletion of fair value uplift and are in US dollars.

Click on, or paste the following link into your web browser, to view the
associated PDF document.

http://www.rns-pdf.londonstockexchange.com/rns/4243W_1-2015-8-18.pdf

For further information please contact:

+------------------------------+------------------------+
|EnQuest PLC                   |Tel: +44 (0)20 7925 4900|
+------------------------------+------------------------+
|Amjad Bseisu (Chief Executive)|                        |
+------------------------------+------------------------+
|Jonathan Swinney (Chief       |                        |
|Financial Officer)            |                        |
+------------------------------+------------------------+
|Michael   Waring (Head of     |                        |
|Communications & Investor     |                        |
|Relations)                    |                        |
+------------------------------+------------------------+
|                              |                        |
+------------------------------+------------------------+
|Tulchan Communications        |Tel: +44 (0)20 7353 4200|
+------------------------------+------------------------+
|Martin   Robinson             |                        |
+------------------------------+------------------------+
|Martin Pengelley              |                        |
+------------------------------+------------------------+