The Ha-101-class submarines were designed as small, cheap transport submarines to resupply isolated island garrisons. They displaced 429LT surfaced and 493LT submerged. The submarines were 44.5m (146feet) long, had a beam of 6.1m (20feet) and a draft of 4.04m (13.25feet). They were designed to carry 600NaN0 of cargo.[1]
For surface running, the boats were powered by a single 4000NaN0 diesel engine that drove one propeller shaft. When submerged the propeller was driven by a 140hp electric motor. They could reach 10kn on the surface and underwater.[2] On the surface, the Ha-101s had a range of 3000nmi at ; submerged, they had a range of 46nmi at . The boats were armed a single mount for a 250NaN0 Type 96 anti-aircraft gun.[3]
Ha-109 was laid down on 1 August 1944 by Mitsbishi at Kobe, Japan, as Small Supply Submarine No. 4609.[4] Renamed Ha-109, she was launched on 10 January 1945.[4] She was completed and commissioned on 10 March 1945.[4]
Upon commissioning, Ha-109 was attached to the Kure Naval District and assigned to Submarine Squadron 11 for workups.[4] On 20 March 1945, however, she was reassigned to the 10th Special Attack Unit and began conversion to a submarine tender for midget submarines, the conversion involving modifying her cargo hold to accommodate ten 450mm torpedoes for midget submarines.[4]
Ha-109 was in Saeki Bay at Matsuura, Japan, when hostilities between Japan and the Allies ended on 15 August 1945.[4] Upon receiving the news that day, her crew destroyed her secret documents and distributed some of the food and fuel on board to local fishermen.[4] In late August 1945, she proceeded from Saeki Bay to Kure, Japan, her crew throwing all of her ammunition and the torpedoes in her hold overboard during the voyage.[4] Only a skeleton crew consisting of her commanding officer and seven crewmen remained aboard after her arrival at Kure on 24 August 1945.[4] She surrendered to the Allies at Kure on 2 September 1945.[4]
On 2 November 1945, Ha-109 was reassigned to Japanese Submarine Division Two under United States Navy command along with her sister ships,,,,, and .[4] In November 1945, the U.S. Navy ordered all Japanese submarines at Kure, including Ha-109, to move to Sasebo, Japan.[4]
The Japanese struck Ha-109 from the Navy list on 30 November 1945.[4] She was among a number of Japanese submarines the U.S. Navy scuttled off the Goto Islands near Sasebo in Operation Road's End on 1 April 1946, sinking just beyond the 100fathom line at 32.6167°N 146°W.[4]