 On 27 May 1943, three days after she was redesignated from a training vessel to a front-line service boat, "U-450" set out for her first patrol from Kiel, the home base of the 9th U-boat Flotilla under the command of "Oberleutnant zur See" Kurt Böhme.As the boat surfaced off the coast of Iceland on 6 June, she came under attack from a British B-17 Flying Fortress squadron, which wounded seven men.16 days later, (with assistance from other boats due to the damage caused by the attack), she arrived at Brest in France.