It has had continuous human habitation since very ancient times and during the pre-Islamic era was the head island and a Buddhist place of learning in Addu.

Royal Navy engineers landed in August 1941 from HMS Guardian to clear and construct airstrips on Gan for the Fleet Air Arm.

Large oil tanks were built on Gan, and on Hitaddu Island on the western edge of the atoll; vital elements for a naval base.

The six major islands were garrisoned by the 1st Royal Marine Coast Defence Regiment, manning shore batteries and anti-aircraft guns.

To facilitate the defence, causeways were built connecting the western islands of Gan, Eyehook (Abuhera), Maradhoo and Hithadhoo and, much later in the war, they were linked by a light railway.

The Japanese remained unaware of the base’s existence until their plans for expansion in South-east Asia had come to nothing, even during their carrier raids in the Indian Ocean in April 1942.

Despite openings into the lagoon being permanently closed by anti-submarine nets, the German U-boat U-183 torpedoed the tanker British Loyalty in March 1944 (she had been previously torpedoed and sunk at Diego Suarez in May 1942, but was raised and towed to Addu for use as an oil storage vessel); this was a long-range shot from outside the atoll through a gap in the anti-torpedo nets.

From Gan Island several rockets of the Kookaburra type were launched from a pad at 0°41' S and 73°9' E.[2] Most of the employees who had experience working for the British military spoke fluent English.