After the Battle of Midway the IJN immediately planned a transport submarine.

Her duties were transportation of troops (110 men, 10 tons freight and two landing craft) in the areas where the enemy had air superiority.

Later, after strong demands from the front commanders, it was decided to arm them with torpedoes for self-defense.

In 1944, the submarines were tasked with transport missions between from mainland Japan to remote islands.

In 1945, several submarines were converted to be Kaiten mother ships and assigned to the suicide attack operations for the Shinchō Tokubetsu Kōgekitai (神潮特別攻撃隊, Sinchō Special Attack Force).