Before the outbreak of World War II in the Pacific, the island of Borneo was divided into five territories. Four of the territories were in the north and under British control – Sarawak, Brunei, Labuan, an island, and British North Borneo; while the remainder, and bulk, of the island, was under the jurisdiction of the Dutch East Indies.
On 16 December 1941, Japanese forces landed at Miri, Sarawak having sailed from Cam Ranh Bay in French Indochina. On 1 January 1942, the Japanese navy landed unopposed in Labuan. Another small Japanese forces took possession of the undefended Labuan on 3 January, where they advance further and landed at Mempakul on North Borneo territory.