Over 760 of these submarines were planned and by August 1945 about 213 had been manufactured. Most of them were constructed at the Yokosuka shipyard. These submarines had a two-man crew and were fitted with two torpedoes along with a 600 kg explosive charge intended to be used on a suicide mission.
Most of the Kairyu submarines were based at Yokosuka to defend the entrance of Tokyo Bay in the event of a United States invasion of mainland Japan. Some of these subs were also stationed in the Moroiso and Aburatsubo inlets on the southern tip of the Miura peninsula where a training school had also been set-up.
Due to Japan's surrender on August 1945, after the atomic bombing of Nagasaki and Hiroshima, none of these submarines ever saw action.