She was built in Hokkaido in 1939, and sunk in the Pacific Ocean by United States Navy aircraft in 1944.

[2] Kokai Maru's owner was Simatani Kisen Kabushiki Kaisha, who registered her at Kobe.

[citation needed] On 10 March 1942, during the Japanese invasion of Salamaua–Lae, US Navy SBD Dauntless aircraft from the carriers USS Lexington and Yorktown damaged her off Lae, New Guinea.

[citation needed] On 21 February 1944 Kokai Maru was part of a convoy off New Hanover Island.

USAAF B-25 Mitchell[citation needed] aircraft bombed her, and she sank at position 02°16′S 150°12′E / 2.267°S 150.200°E / -2.267; 150.200.