Kaiyo was a Japanese escort aircraft carrier, the keel of which was laid in 1937, launched in December 1938, and commissioned in 1939. The ship was 166.5 meters long, 21.9 meters wide, and had a full displacement of 13,800 tons. The maximum speed of the aircraft carrier Kaiyo was around 24 knots, and its main armament consisted of only 24 on-board planes.
Kaiyo was originally launched as the Argentina Maru passenger ship, however, at the beginning of World War II, the Navy commandeered the vessel, and in December 1942 began converting it into an aircraft carrier. Rebuilding was completed in 1943, and in November of that year Kaiyo entered service as an escort aircraft carrier. During World War II, it served primarily as an aircraft transporter, carried out ZOP (anti-submarine anti-submarine) activities and covered, more importantly, convoys. With time, it became primarily a school unit. At the very end of the conflict - in July 1945 - it was severely damaged by British on-board aviation. Renovation of the ship was not undertaken and the vessel was scrapped by 1948.