Today
Prior to WWII, it was politically divided between the Dutch and British into threee regions, Sarawak, North Borneo and Borneo. When it was attacked on December 16, 1941 it was only defended by a token battalion of Punjabi infantry. Today, the northern and western parts of the island are part of Malaysia, and the southern parts Indonesia. A small area on the north-west coast is Brunei.

Japanese Occupation
The small Allied air force could do little against greatly superior Japanese airpower. Allied naval strength in the area consisted of only 9 cruisers, 23 destroyers, and 36 submarines. Nevertheless, though no match for the vastly superior Japanese Fleet, the Allied warships attacked repeatedly. In the early dark hours of January 24, 4 Allied destroyers attacked a large convoy off Balikpapan, Borneo. In this, the Battle of Makassar Strait, the destroyers escaped unharmed after sinking 4 Japanese transports and a patrol ship and damaging other vessels. Subsequent engagements - the Battle of Lombok Strait (February 18-19) and the Battle of the Java Sea (February 27) were not as successful for the Allies. In the latter losses from Japanese air and naval attacks were so severe that the surviving Allied warships were withdrawn from the Java Sea to Tjilatjap (Chilachap) on the south coast of Java. On February 28, 2 Allied cruisers, the Houston and the Perth, which were attempting to escape southward through Soenda (now Sunda) Strait, suddenly ran into a huge Japanese invasion armada in the process of assaulting Batavia (now Djakarta). The cruisers were destroyed, but only after sinking 3 loaded Japanese transports.

The few Allied aircraft and warships that remained were ordered to withdraw to Australia. On March 9, the Dutch finally surrendered the Netherlands East Indies to the Japanese. Allied attention was now directed to the defense of Australia.

The Forgotten War In Borneo
The ground fighting on Borneo at the very end of WWII is often considered a "forgotten war" because it is often overlooked as a campaign, occuring in the final weeks of the Pacific war, and because its invasion was largely due to rivalrys between Generals, and concerned battle plans that never came to furition due to the end of the war. Because Commonwealth air forces were not allowed to use the American airfields in the recently liberated Philippines, they sought Borneo as a staging area for their planned liberation of Singapore. In May - July 1945, the Australian 1st Corps commanded by Lt. General Morshead and undertook the largest Australian operation of war. The war ended in August, as and so did Borneo's strategic signifigance.