Attack on Sydney Harbour

Overview

From 31 May to 8 June 1942, during World War II, Imperial Japanese Navy submarines made a series of attacks on the Australian cities of Sydney and Newcastle. On the night of 31 May – 1 June, three Ko-hyoteki-class midget submarines, each with a two-member crew, entered Sydney Harbour, avoided the partially constructed Sydney Harbour anti-submarine boom net, and attempted to sink Allied warships. Two of the midget submarines were detected and attacked before they could engage any Allied vessels. The crew of M-14 scuttled their submarine, whilst M-21 was successfully attacked and sunk. The crew of M-21 committed suicide. These submarines were later recovered by the Allies. The third submarine attempted to torpedo the heavy cruiser USS Chicago, but instead sank the converted ferry HMAS Kuttabul, killing 21 sailors. This midget submarine's fate was unknown until 2006, when amateur scuba divers discovered the wreck off Sydney's northern beaches.

Overview adapted from Wikipedia, licensed under CC BY-SA 4.0.

Significance

The attack on Sydney Harbour in late May and early June 1942 marked the furthest penetration of Japanese naval forces into Australian coastal waters during the Pacific War, demonstrating that Allied port facilities in the Southern Hemisphere were within reach of Imperial Japanese Navy submarine operations. Three Ko-hyoteki-class midget submarines entered Sydney Harbour itself, evading a partially constructed anti-submarine boom net and pressing close enough to attempt torpedo attacks on Allied warships. Although two of the three submarines were neutralized before engaging any targets, the third succeeded in sinking the converted ferry HMAS Kuttabul, killing 21 sailors — the only direct casualties of the harbour attack. The episode exposed vulnerabilities in Sydney's harbor defenses at a moment when the Allied position in the Pacific remained precarious. A subsequent submarine bombardment of Newcastle extended the operational footprint of the Japanese raid along the Australian coast. The attack generated significant public alarm in Australia about the security of its major cities and contributed to pressure to strengthen coastal and harbor defenses.

Tactics

Commanders (2)