"U-300" served with the "8th U-boat Flotilla" for training, the "7th U-boat Flotilla" from 1 August 1944 to 30 September 1944 and the "11th U-boat Flotilla" from 1 October 1944 to 22 February 1945 for operations.She carried out three patrols, sinking two ships, and damaged two more before she was sunk on 22 February 1945 off Quarteira, Portugal.