They were small and limited in capability but were thought to be a successful class.

[1][2][3] They shared many of the same characteristics with small design improvements.

They were small submarines with limited capability[1] but considered handy and a successful class.

Two shafts were powered by two Sulzer-Mitsubishi diesel engines creating 1,350 brake horsepower (1,010 kW) and two electric motors creating 1,700 shaft horsepower (1,300 kW).

[1][a] The Natsushios were armed with three 533-millimeter (21 in) torpedo tubes in the bow.