As war clouds gathered over Singapore the RAF started building up their forces in the Far East in the late 1930s and early 1940s. Seletar airfield was the target of Carpet bombing when Japanese navy bombers conducted the First air raid on Singapore, sometime after their ground forces invaded Kota Bahru. It was abandoned when the Japanese took Johore Bahru, which brought their artillery in range of the airfield.
When the Japanese launched their invasion of Malaya and Singapore, Seletar housed the RAF’s 205 Sqn with PBY Catalina Flying boats and 36 and 100 Sqns with obsolete Vickers Vildebeest torpedo bombers, along with 151 Maintenance Unit. These units stayed until Jan-Feb 1942, soon before the surrender to the invading Japanese.
During the Japanese occupation Seletar was under the Imperial Japanese Navy Air Service, and a number of IJN squadrons were based or transited through there mainly, for training. Among the units known to be based there during this time were 936 Kokutai (B5N Kate, D3A Val and E13A1 Jake), 381 Kokutai (A6M Zero and J2M Raiden). The 601 Kokutai was also stationed there for training in early before its destruction on board Japanese aircraft carriers during the Battle of Philippine Sea (Marianas Turkey Shoot) in June. Seletar’s present runway was built during the Japanese Occupation
After World War 2 the base went back to the RAF, and in the late 1940s and 1950s the base was heavily involved in the Malayan Emergency, with Beaufighters, Spitfires and Mosquitos based there while operating against Malayan Communist insurgents. Among the many squadrons based there during this time were Nos 60, 81 and 205 Sqns of the RAF