German submarine U-30 was a Type VIIA U-boat of the Nazi German Kriegsmarine that served during World War II. She was ordered in April 1935 in violation of the Treaty of Versailles, which prevented the construction and commissioning of any U-boats for the German navy, and as part of the German naval rearmament program known as Plan Z. She sank the liner SS Athenia, the first ship sunk in World War II, on 3 September 1939, under the command of Fritz-Julius Lemp. She was retired from front-line service in September 1940 after undertaking eight war patrols, having sunk 17 vessels and damaging two others. U-30 then served in a training role until the end of the war when she was scuttled. She was later raised and broken up for scrap in 1948.