The IJN planned to build 12 boats, but only 10 vessels were completed by the end of the war.

[2] Several boats were converted to tankers or mother ships for Kō-hyōteki model D "Kōryū" (甲標的丁型 蛟龍) midget submarines.

[3] For surface running, the boats were powered by a single 400-brake-horsepower (298 kW) diesel engine that drove one propeller shaft.

[4] On the surface, the Ha-101s had a range of 3,000 nautical miles (5,600 km; 3,500 mi) at 10 knots (19 km/h; 12 mph); submerged, they had a range of 46 nmi (85 km; 53 mi) at 2.3 knots (4.3 km/h; 2.6 mph).

The boats were armed a single mount for a 25 mm (1 in) Type 96 anti-aircraft gun.