The Battle of Tarakan was the first stage in the Borneo campaign of 1945. It began with an amphibious landing by Allied forces on 1 May, code-named Operation Oboe One; the Allied ground forces were drawn mainly from the Australian 26th Brigade, but included a small element of Netherlands East Indies personnel. The main objective of the landing was the capture of the island's airfield. While the battle ended with success for the Allied forces over the Japanese defenders, this victory is generally regarded as having not justified its costs. The airfield was so heavily damaged that it ultimately could not be repaired in time to make it operational for other phases of the Allied campaign in Borneo.

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.