In September 2002, Petroplus International applied for governmental approval for the construction of an LNG terminal in Waterston, Milford Haven in Wales, UK. BG Group and Petronas entered into the project, called Dragon LNG, in November 2004. By the close of 2004, the Dragon LNG was granted permission by the Pembrokeshire County Council. In 2006, Petroplus transferred its 20% stake in the Dragon LNG venture to 4Gas. The joint venture's developers include BG Group with 50%, Petronas with 30% and 4Gas with 20%.

The Dragon LNG terminal comprises an unloading jetty for LNG tankers, two LNG storage tanks with a storage capacity of 320,000 cubic meters, an LNG gasification unit and pipeline connecting to the National Transmission System. The terminal can receive from 71,000 to 165,000 cubic meters of LNG from tankers every day and send out 700,000 cubic meters of natural gas per hour.

The LNG terminal was built at the site of the Gulf Oil Refinery, which was in operation from the mid-1960s to 1997. In 1998, 4Gas bought the refinery from Chevron and operated it as a storage and related oil service location called 4Gas Tankstorage Milford Haven Ltd. until construction began on Dragon LNG. By repurposing the Gulf Oil Refinery location, the berth for the LNG tankers only needed to be refurbished rather than built from scratch.

Whessoe Oil & Gas served as the EPC contractor for the terminal construction, overseeing both the imporation terminal and the regasification plant. A VolkerWessels subsidiary, Volker Stevin Construction Europe, constructed and installed the pipeline and refurbishing the jetties. M.W. Kellogg was subcontracted to provide the design development and certain key staff to the project during the construction phase.

Dragon LNG completed its commissioning phase and began commercial operation on August 25, 2009. The import, storage, and regasification terminal has a start-up capacity of 6 billion cubic meters per annum (bcma) and expansion permitted to 9 bcma.