Japanese Attack on Sydney Harbour
May 31, 1942
In late May and early June 1942, the war was brought home to Australians on the east coast when the Japanese attacked Sydney Harbour from the sea.
On 31 May 1942, three Japanese submarines, sitting about 13km out from Sydney Harbour, each launched three Type A midget submarines for a surprise attack on shipping in Sydney Harbour.
While electronic detection equipment late that evening picked up the signature of the first midget submarine, it was thought to be a ferry or another vessel passing by. After an object caught in in an anti-submarine net was spotted and identified as a submarine, the general alarm was raised. Soon afterwards, the midget submarine’s crew, realising they were trapped, blew up their submarine and themselves.
The second midget submarine was spotted by the crew of the USS Chicago who opened fire, but it escaped. Just after midnight, a torpedo fired by the second submarine and intended for USS Chicago instead hit the naval depot ship HMAS Kuttabul – a converted harbour ferry – which was moored at Garden Island as an accommodation vessel.
Nineteen Australian and two British sailors on the Kuttabul died, the only Allied deaths resulting from the attack. The second midget submarine disappeared but third submarine did not make it far into the harbour. When it was discovered and attacked with depth charges from naval vessels, the two crewmen shot themselves.
The three mother submarines, realising their midget submarines were not returning, left the region, although it is believed that the second midget submarine was responsible for further attacks on merchant ships and also shelling in Sydney Harbour a week later.

Sources
Source: (Department of Veterans’ Affairs) (2022)