Just before the attack on Pearl Harbor, "I-53" began a patrol north of the Anambas Islands to support "Operation E", the Japanese invasion of Malaya. Hostilities began in East Asia on 8 December 1941 (7 December across the International Date Line in Hawaii, where Japan began the war with its attack on Pearl Harbor). After an uneventful patrol, "I-53" arrived at Cam Ranh in Japanese-occupied French Indochina.