The Japanese made a three-pronged attack of the chain of islands including Java, Sumatra and Borneo, which were a major source of oil and thus a critical part of the Japanese strategy for a Southern Resources Area. They were gallantly opposed by a heavily outnumbered, mixed force of Australian, British, Dutch, American and other allied forces (known as ABDA command) lead by General Wavell who attempted to slow the advance but were beaten by a more numerous, better organised and equipped opponent. Sarawak and Brunei fell between 16th and 23rd December, the rest of Northern Borneo was occupied by 10th January. Celebes fell on the 11th. By February, the Japanese were closing in on Java from three sides and on the 14th, Japanese paratroopers established a forward base on Sumatra. Southern Borneo was invaded on the 16th February, Bali on the 19th and Timor by the 24th. By the 25th, it was obvious that the Japanese had won in this area so ABDA command was dissolved and Gen. Wavell was ordered to leave (to resume command in India). The Dutch Admiral Helfrich who assumed command of the area continued the fight, but after the Battle of the Java Sea and the invasion on Java on the 1st March, the allies surrendered.

• Macassar Strait 23 January 1942
• Madoera Strait 04 February 1942
• Lombok Strait (Bandoeng) 19 February 1942 - 20 February 1942
• Java Sea 27 February 1942