At the start of the Pacific War, "Chōkai" supported the invasion of Malaya and participated in the pursuit of the Royal Navy's battleship Force Z. During January and February 1942, "Chōkai" was involved in operations to seize the oil-rich Dutch East Indies and the island of Borneo. Steaming near Cape St. Jacques, "Chōkai" struck a reef, sustaining hull damage on 22 February 1942. On 27 February, she reached Singapore for repairs.