The Ha-101-class submarine (波百一型潜水艦, Ha-hyaku-ichi-gata Sensuikan) was a transport submarine built for the Imperial Japanese Navy (IJN) during World War II. The IJN planned to build 12 boats, but only 10 vessels were completed by the end of the war. The IJN called these submarines Sen'yu-Shō type submarine (潜輸小型潜水艦, Sen-Yu-Ko-gata sensuikan). The type name, was shortened to Yusō Sensuikan Ko-gata (輸送潜水艦小型, Transport Submarine-Small Type). Several boats were converted to tankers or mother ships for the Kō-hyōteki model D "Kōryū" (甲標的丁型 蛟龍) midget submarines.