There was considerable Axis naval activity in Australian waters during the Second World War, despite Australia being remote from the main battlefronts. German and Japanese warships and submarines entered Australian waters between 1940 and 1945 and attacked ships, ports and other targets. Among the best-known attacks are the sinking of HMAS Sydney by a German raider in November 1941, the bombing of Darwin by Japanese naval aircraft in February 1942, and the Japanese midget submarine attack on Sydney Harbour in May 1942. About 40 Allied merchant ships were damaged or sunk off the Australian coast by surface raiders, submarines and mines. Japanese submarines also shelled three Australian ports and submarine-based aircraft flew over several Australian capital cities.
The Axis threat to Australia developed gradually and until 1942 was limited to sporadic attacks by German armed merchantmen. The level of Axis naval activity peaked in the first half of 1942 when Japanese submarines conducted anti-shipping patrols off Australia's coast, and Japanese naval aviation attacked several towns in northern Australia. The Japanese submarine offensive against Australia was renewed in the first half of 1943 but was broken off as the Allies pushed the Japanese onto the defensive. Few Axis naval vessels operated in Australian waters in 1944 and 1945, and those that did had only a limited impact.
Due to the episodic nature of the Axis attacks and the relatively small number of ships and submarines committed, Germany and Japan were not successful in disrupting Australian shipping. While the Allies were forced to deploy substantial assets to defend shipping in Australian waters, this did not have a significant impact on the Australian war effort or American-led operations in the South West Pacific Area.
Australia Station and Australian defences
The maritime approaches to Australia were designated the Australia Station prior to the outbreak of war. This vast area consisted of the waters around Australia and eastern New Guinea, and stretching south to Antarctica. From east to west, it stretched from 170° east in the Pacific Ocean to 80° east in the Indian Ocean, and from north to south it stretched from the Equator to the Antarctic. While the eastern half of New Guinea was an Australian colonial possession during the Second World War and fell within the Australia Station, the Japanese operations in these waters formed part of the New Guinea and Solomon Islands campaigns and were not directed at Australia.
The defence of the Australia Station was the Royal Australian Navy's (RAN) main concern throughout the war. Although RAN ships frequently served outside Australian waters, escort vessels and minesweepers were available to protect shipping in the Australia Station at all times. These escorts were supported by a small number of larger warships, such as cruisers and armed merchant cruisers, for protection against surface raiders. Important military shipping movements were escorted from the start of the war, but convoys were not instituted in Australian waters until June 1942. The Australian naval authorities did, however, close ports to shipping at various times following real or suspected sightings of enemy warships or mines prior to June 1942.
The Royal Australian Air Force (RAAF) was also responsible for the protection of shipping within the Australia Station. Throughout the war, RAAF aircraft escorted convoys and conducted reconnaissance and anti-submarine patrols from bases around Australia. The main types of aircraft used for maritime patrol were Avro Ansons, Bristol Beauforts, Consolidated PBY Catalinas and Lockheed Hudsons. Ansons were the main type available during the first years of the war, but were not well suited to this task due to their short range and modest weapon-carrying capacity. The introduction of Beauforts and Hudsons considerably improved the RAAF's maritime patrol and anti-submarine capacities. A network of airfields along the Australian coastline was established over the course of the war to support the RAAF's maritime patrol operations. Anti-submarine work required intensive efforts by the RAAF aircrew. For instance, aircraft needed to sweep the entrance to harbours before convoys departed and then constantly patrol over them while they were at sea.