The Borneo campaign or Second Battle of Borneo was the last major Allied campaign in the South West Pacific Area during World War II to liberate Japanese-held British Borneo and Dutch Borneo. Designated collectively as Operation Oboe, a series of amphibious assaults between 1 May and 21 July 1945 were conducted by the Australian I Corps, under Lieutenant-General Leslie Morshead, against Imperial Japanese forces who had been occupying the island since late 1941 – early 1942. The main Japanese formation on the island was the Thirty-Seventh Army under Lieutenant-General Masao Baba, while the naval garrison was commanded by Vice-Admiral Michiaki Kamada. The Australian ground forces were supported by US and other Allied air and naval forces, with the US providing the bulk of the shipping and logistic support necessary to conduct the operation. The campaign was initially planned to involve six stages, but eventually landings were undertaken at four locations: Tarakan, Labuan, North Borneo and Balikpapan. Guerilla operations were also carried out by Dayak tribesmen and small numbers of Allied personnel in the interior of the island. While major combat operations were concluded by mid-July, localised fighting continued throughout Borneo until the end of the war in August. Initially intended to secure vital airfields and port facilities to support future operations, preparatory bombardment resulted in heavy damage to the island's infrastructure, including its oil production facilities. As a result, the strategic benefits the Allies gained from the campaign were negligible.
Australian troops advancing towards Brunei
US Navy Landing Craft Infantry crowded with Australian soldiers prior to the landing at Labuan
Australian infantrymen passing a Matilda tank in the interior of Tarakan
Australian soldiers disembarking from a US Navy LST at Labuan on 10 June 1945
South West Pacific Area (SWPA) was the name given to the Allied supreme military command in the South West Pacific Theatre of World War II. It was one of four major Allied commands in the Pacific War. SWPA included the Philippines, Borneo, the Dutch East Indies, East Timor, Australia, the Territories of Papua and New Guinea, and the western part of the Solomon Islands. It primarily consisted of United States and Australian forces, although Dutch, Filipino, British, and other Allied forces also served in the SWPA.
General Douglas MacArthur and Australian Prime Minister John Curtin.
Command Organization, Southwest Pacific Area, July 1943
Royal Australian Air Force chief, Air Vice Marshal George Jones (left) meeting the Allied air forces commander in the SWPA, Lieutenant General George Kenney (right) in mid-1945, in Manila.
Allied Naval Forces SWPA, commander Vice Admiral Thomas C. Kinkaid (centre left) with MacArthur (centre) on 28 February 1944 on USS Phoenix during the bombardment of Los Negros Island, at the commencement of the Admiralty Islands campaign.