The Pacific War, sometimes called the Asia-Pacific War, was the theater of World War II that was fought in the Pacific and Asia. It was fought over a vast area that included the Pacific Ocean and islands, the South West Pacific, South-East Asia, and in China. I began on December 7/8, 1941, when Japan invaded Thailand and attacked the British possessions of Malaya, Singapore, and Hong Kong as well as the United States military and naval bases in Hawaii, Wake Island, Guam and the Philippines.