 After training with the 5th U-boat Flotilla at Kiel, "U-953" was transferred to the 3rd U-boat Flotilla based at La Pallice (in southwestern France), for front-line service on 1 June 1943.She sailed on ten war patrols, but sank only one ship of .She was transferred to the 33rd U-boat Flotilla on 15 October 1944, under the command of her second skipper, "Oblt.z.S."