The Dutch East Indies campaign was the Japanese conquest of the Dutch East Indies during the early days of the Pacific theater of World War II. Japan launched a joint land and naval campaign that defeated the ABDA Command and destroyed its fleet at the Battle of the Java Sea, enabling the takeover of the Dutch East Indies and the fatal weakening of Dutch influence in the islands.
Japan had coveted the East Indies for their wealth of rubber plantations and oil fields. On joining World War II, Japan sent the fleet carriers Akagi, Kaga, Hiryu, and Soryu and a light carrier along with four fast battleships, 13 heavy cruisers, and many light cruisers and destroyers to support their amphibious assaults on the East Indies. While Japan had lost 93% of its oil supply after President Franklin D. Roosevelt ordered an embargo on 26 July 1941, the Dutch made matters worse by joining the embargo a month later. By late November, the Dutch government began preparing for war with Japan, mobilizing the Royal Netherlands Navy and the KNIL Air Force.
On 8 December 1941, the day after Japan's attack on Pearl Harbor, the Netherlands declared war on Japan and recalled its merchantmen to their nearest ports. Hisaichi Terauchi, commander of the Southern Expeditionary Army Group, began the campaign by sending Hitoshi Imamura's IJA 16th Army to attack Borneo. Japanese forces landed at Miri in Sarawak on 17 December 1941 and at Seria, Kuching, Jesselton, and Sandakan between 15 December 1941 and 19 January 1942, after which they launched a three-pronged assault southward. The Eastern Force advanced from Jolo and Davao in the Philippines to capture Sulawesi, Ambon Island, and Timor, while the Center Force was to capture oil fields and airports in Tarakan Island and Balikpapan and the Western Force would attack and capture the oil refineries and airfields in Palembang. The Japanese assault began on 11 January, the same day as Japan's formal declaration of war on the Netherlands.
The Allies of the Pacific combined their forces under the ABDA Command, which was activated on 15 January 1942 with Archibald Wavell as its commander. While the British prioritized the defense of Singapore and the sea routes to Ceylon and British India, the Americans and Australians favored the protection of bases in Southeast Asia that would be needed for counterattacks and the Dutch refused to give up their second homeland of Java and Sumatra without a fight. Dutch forces destroyed their oil fields before they could be captured by the Japanese, and several Japanese vessels were destroyed or damaged by Allied naval and air counterattacks, but the Japanese were able to capture parts of the Celebes and Borneo by late January and used them as bases for air raids. By February, the Japanese had also landed on Sumatra and encouraged a revolt in Aceh. Most of the Allied naval components were destroyed at the Battle of the Java Sea, the Battle of Sunda Strait, and the Second Battle of the Java Sea, and the Allied land forces were overwhelmed within two months. However, the Allies continued to wage a guerrilla campaign on Timor until 10 February 1943, when the Japanese occupied both the Dutch and Portuguese sections of the island. On 8 March 1942, the Dutch East Indies surrendered to Japan, and the British and American forces were forced to comply with the surrender. The Allies did not attempt to retake Java, Sumatra, Timor, or Bali for the rest of the war, and the Japanese would remain on the islands until Japan's final surrender in August 1945. 1,000 Japanese occupiers would desert from their units at the end of the war and aid Indonesian rebels during the Indonesian National Revolution.