巽他海峡
"Soemba" sailed for the East Indies shortly after her commissioning and remained there until the start of the Pacific War in 1941. The ship fought Japanese forces in and around the Sunda Strait during the collapse of the East Indies. She was among the covering naval forces during transshipment of troops bound for Malaya from at Ratai Bay, Sunda Strait to smaller transports beginning 20 January 1942.