[5][1] Apart from a short visit to the UK to take part in the 1937 Coronation Review at Spithead, the squadron remained in the Mediterranean until the outbreak of the war in September 1939.

[1] Glorious was then sent to patrol the Indian Ocean, but was recalled to home waters in early 1940, and 812 Squadron was transferred to RAF Coastal Command[2] to take part in mining and bombing operations in the low countries and in the Dunkirk evacuation.

The squadron received new aircraft equipped with ASV (Air to Surface Vessel) radar, enabling them to sink the U-boat U-451 on the night of 21 December 1941,[7] and to damage five others.

The squadron returned to the UK in April 1942 aboard USS Wasp (CV-7), and were reattached to Coastal Command in September to fly operations over the English Channel.

[8] The group sailed for Australia aboard Vengeance, and were based at HMS Nabswick (MONAB V) at Jervis Bay from 22 July 1945, where they trained for the planned invasion of Japan.

After the Japanese surrender on 8 August, they were temporarily based at Ponam in the Admiralty Islands, before being sent to Hong Kong, arriving at HMS Nabcatcher (MONAB VIII) at Kai-Tak, in October 1945, and remaining there until the end of the year.

812 Squadron was re-equipped with the Fairey Firefly, and returned to Australia in January 1946, where they were based HMS Nabthorpe (MONAB VI) at Schofields, New South Wales, while Vengeance was in dry dock for repairs.

In April 1956 it sailed to the Mediterranean in Eagle, taking part in visits and exercises before flying home from Malta, and was disbanded on arrival at Lee-on-Solent on 13 December 1956.