The Unryū-class Aircraft carriers (雲龍型航空母艦, Unryū-gata kōkūbokan) were built under the Maru Kyū Programme (Ship #302 in 1941) and the Kai-Maru 5 Programme. The idea for the IJN was to build more fleet carriers as quickly as possible thus the design for these ships was based on the aircraft carrier Hiryū rather than the newer and more sophisticated Taihō or the Shōkaku-class.

The ships were lightly built, and the main difference from Hiryū was that the carriers' island was placed on the starboard side of the ships. The carriers were capable of carrying 63 aircraft in two hangars, and were fitted with two elevators. The Unryū class carried a smaller quantity of aviation fuel as Hiryū with fuel tanks protected by concrete. The ships were fitted with the same propulsion system used in the aircraft carrier Sōryū to reach 34 knots (63 km/h).

Originally, a total of 15 carriers were planned, but by the end of the Pacific War only three were built and another three were incomplete.

In game, while Unryuu-class' last 2 slot pre-Kai and last slot post-Kai can only carry extremly few planes, but those slots can be used for equipment like SCAMP or Saiun. They also have weak firepower, on par with CarDiv1 and lagging far behind CarDiv2 and CarDiv5. However, their sortie cost is just roughly 2/3 of CarDiv1. Their HP is comparatively lower but there are higher armor and evasion, plus low hp mean low repair time.