During her career U-30 was involved in eight war patrols, under the command of Kptlt. Fritz-Julius Lemp. U-30's career began ingloriously, when on 3 September 1939 she sank the 13,581 ton passenger ship SS Athenia, the first ship sunk in World War II. Lemp's career was almost wrecked, but he pleaded it was a genuine error - mistaking her for an armed merchant cruiser, which he claimed was zig-zagging.