The island's location was also significant, as it sat across the main sea routes between north Asia, Malaya and the NEI. The European colonisers had developed oil fields and their holdings exported other raw materials. īorneo was strategically important during World War II. Most of the coastline was lined with mangroves or swamps. Borneo has a tropical climate and was mainly covered by dense jungle at the time of World War II. The great majority lived in small villages, with Borneo having less than a dozen towns. As of 1941, the island's population was estimated to be 3 million. Prior to World War II, Borneo was divided between British Borneo, in the north of the island and Dutch Borneo in the south the latter formed part of the Netherlands East Indies (NEI). As a result, the strategic benefits the Allies gained from the campaign were negligible. 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. While major combat operations were concluded by mid-July, localised fighting continued throughout Borneo until the end of the war in August. Guerilla operations were also carried out by Dayak tribesmen and small numbers of Allied personnel in the interior of the island.

The campaign was initially planned to involve six stages, but eventually landings were undertaken at four locations: Tarakan, Labuan, North Borneo and Balikpapan. 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 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. 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 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.

Dutch navy world war 2