Japanese submarine Ro-45

Ro-45 was an Ro-35-class submarine of the Japanese Navy during World War II. It was completed and commissioned at Mitsubishi Shipbuilding on January 11, 1944. It was based in the Maizuru Naval District under the command of Commander Hamazumi Yoshihisa. It was later reassigned to the Sixth Fleet and sent to Truk.

Differing accounts of the submarine's fate exist. Some sources suggest that it was sunk off of the coast of Saipan by the USS Seahorse on 20 April 1944. Other sources, however, indicate that the ship participated in an attack on an American task force near Truk on April 30, 1944. Even these sources differ on the ultimate fate of the ship: some claim it was sunk during the attack, while others say that it was later presumed lost on May 20, 1944.