In late August 1941, B-Dienst (the German naval codebreaking organisation) became aware of a large concentration of Allied merchant ships in the region of the North Atlantic south of Iceland. Admiral Karl Dönitz ordered 16 U-boats to the area. "U-570" was to be one of these and, on the morning of 24 August, she put to sea on her first war patrol. Her planned mission was to patrol the area south of Iceland before proceeding to the U-boat base at La Pallice, France. She carried provisions for four weeks at sea.