On 4 September, Waterman was assigned to TG 30.6, whose duty it was to evacuate Allied prisoners of war (POW's) from nearby prison camps. That afternoon, the destroyer escort entered the harbor at Yokohama and transported POW's to nearby hospital ships, receiving ships, and Kizarazu airfield. "Waterman" continued that work of mercy until 10 September, when she departed the Tokyo area with TU 30.6.3—four LSM's and sister ship — bound for Shiogama, on the eastern coast of Honshū, through which port the POW's from the Sendai camp were being evacuated.