Kaiyō (海鷹, meaning Sea Hawk)[1] was an escort carrier operated by the Imperial Japanese Navy (IJN) during World War II.

The ship was ordered as the fast luxury passenger liner Argentina Maru by Osaka Shosen Kaisha (OSK) in 1938.

As part of her conversion, her original diesel engines, which had given her a top speed of 21.5 knots (39.8 km/h; 24.7 mph), were replaced by a pair of destroyer-type geared steam turbine sets with a total of 52,000 shaft horsepower (39,000 kW), each driving one propeller.

[4] The ship's flight deck was 21.9 meters (72 ft) wide[5] and Kaiyō had a single hangar, served by two aircraft elevators, mounted on the centerline.

[4] The ship's primary armament consisted of eight 40-caliber 12.7 cm Type 89 anti-aircraft (AA) guns in twin mounts on sponsons along the sides of the hull.

[6] Kaiyō was also initially equipped with eight triple 25 mm Type 96 light AA guns, also in sponsons along the sides of the hull.

[10] Early warning was provided by a Type 2, Mark 2, Model 1 air search radar that was installed on the side of the flight deck in November 1943.

On 10 February, en route to Truk from Palau, the submarine Permit made a night attack on Kaiyō, but the torpedoes missed.

She was briefly docked at Kure Naval Arsenal in early July to have more 25 mm AA guns fitted.

[2] On 25 October, Kaiyō ferried a dozen transport aircraft to Keelung, Taiwan, and arrived at Kure on 2 November.

The ship was assigned to escort Convoy HI-83 to Singapore via Taiwan and Hainan Island on 25 November and arrived on 13 December.

After arriving at Moji on 13 January 1945, the ship was transferred to Kure and assigned to pilot training in the Inland Sea.

The amount of damage inflicted by these attacks, if any, is unknown, but they did cause Captain Shuichi Osuga to abandon attempts to repair the ship.

Kaiyō was struck from the Navy List on 20 November and scrapped in place from 1 September 1946 and 30 January 1948 by Nissan Salvage.