Ro-44 was a Kaichu VII coastal submarine, a sister of the Ro-35 boats. Tamano Heavy Industries, the Mitsui yard at Tamano, laid her down on 14 February 1942 and launched her on 11 November 1942. Mochitsura Hashimoto was her fitting-out officer from 25 July 1943, and he became her captain when she was completed. The service record starts her in the 11th Submarine Squadron on 13 September 1943. One list prints 19 September as the day she was completed. She worked in home waters. No attack is recorded while he had her. He left on 14 May 1944 for the new I-58, a different boat from the old hull that had been renumbered I-158.
Sadao Uesugi took her that day. On 16 June 1944 she was on the surface, about 110 miles east of Eniwetok, at 11°13′N, 164°15′E. Burden R. Hastings, steaming alone from Majuro toward Pearl Harbor, picked her up on radar in the middle of the night, got no answer to a lamp challenge, and attacked. After the explosion the destroyer escort recovered wreckage, including a spare-parts box whose characters named Ro-44. The officer list counts 72 dead and none saved. She was struck on 10 August 1944. Uesugi was lost with her. No other ship is credited with the sinking.