Ayatosan Maru (綾戸山丸 貨物船) was a 9,788 gross ton (10,930DWT) freighter that was built by , Tamano for Mitsui & Co. Ltd. launched in 1939. She had been intended to run the New York passenger and freight run, however she was requisitioned by the Imperial Japanese Navy and fitted out as a high-speed transport, which was completed in May 1941. During the invasion of Malaya she was damaged by Royal Australian Air Force Lockheed Hudson light bombers and a blaze broke out which was later extinguished. She was also damaged by a torpedo from the Dutch submarine HNLMS O-16.