Kaiwo Maru (海王丸) is a Japanese former training barque. She was built by Kawasaki Shipbuilding Corporation in Kobe, and was launched on 27 January 1930 alongside her sister ship Nippon Maru. She was operated by the Tokyo Institute for Maritime Training to train officers for Japan's merchant marine. At the beginning of World War II, her sailing rig was removed and she served as a training and postwar transport motorship. In 1955, her rig was reinstalled and she resumed her training voyages until she was replaced in 1989 by her successor, also named Kaiwo Maru.