Fremantle submarine base

Fremantle submarine base was the utilisation of Fremantle Harbour as a submarine base in World War II.

Knowledge of its existence was very carefully guarded as a wartime secret. However, in August 1945, newspaper reports openly acknowledged the impact of the forces' activity.

The establishment of the base was directly related to what was known as the Japanese Scare of March 1942, the most significant event for Western Australia being the attack on Broome.

The base later became a major US Navy facility, with submarines based there attacking Japanese shipping throughout South East Asia. It involved mainly submarines from the US navy, but also included submarines from other forces.

When it was fully active the base saw 160 Dutch, American and British submarines pass through the harbour.

The base was tied in with the Indian Ocean campaign of 1942–45. Military historians looking at the strategy in the South East Asian Theatre look upon the command of the Commander Submarines, South West Pacific (COMSUBSOWESPAC), and the facility of the Fremantle base as integral to successes in 1943 onwards.

Various buildings and properties in Fremantle were requisitioned as part of the support of the base, and remained so until late 1945. Other facilities further from the coast were also utilised for support, such as the Byford armament depot, which stored torpedoes and mines. Also anti-aircraft gun installations were set up near the base. 4000 tons of ammunition including torpedoes was stored at US Navy 137 - 7 Naval Ammunition Depot (7NAD) at Springhill, near Northam

Coastal defences for the seaward approaches to Fremantle, included batteries on Rottnest Island (2), the suburban beaches between Swanbourne and Point Peron at the lower end of Cockburn Sound (3), Garden Island (4), as well as at the mouth of the harbour (2).

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