On the morning of 1 July 1945 hundreds of warships and vessels from the United States Navy, the Royal Australian Navy (RAN) and the Royal Netherlands Navy lay off the coast of Balikpapan, an oil refining centre on Borneo’s south-east coast. An Australian soldier described the scene: “Landing craft are in formation and swing towards the shore. The naval gunfire is gaining momentum, the noise from the guns and bombs exploding is terrific … waves of Liberators [heavy bombers] are pounding the area.”
This offensive to land the 7th Australian Infantry Division at Balikpapan was the final in a series amphibious operations conducted by the Allies to liberate areas of Dutch and British territory on Borneo. It was the largest amphibious operation conducted by Australian forces during the Second World War. Within an hour some 16,500 troops were ashore and pushing inland, along with nearly 1,000 vehicles. Ultimately more than 33,000 personnel from the 7th Division and Allied forces were landed in the amphibious assault. Balikpapan is often cited as an example of the expertise achieved by Australian forces in amphibious operations during the war. It was a remarkable development. Four years earlier, the capability of Australia or even the United States to conduct amphibious operations in the South-West Pacific Area (SWPA) was limited, if not non-existent.
The SWPA was a vast theatre that included Australia, Papua and New Guinea, the Netherlands East Indies (now Indonesia) and the Philippines, with Allied forces under the command of General Douglas MacArthur. The term “amphibious warfare” was generally adopted in preference to “combined operations”, the term favoured in the European theatres. In 1944, the Australian army defined “amphibious warfare” as “operations in which Navy, Army and Air Force participate together in a coordinated plan involving the transport of army assaulting forces by sea.”