German submarine U-19 was a Type IIB U-boat of Nazi Germany's Kriegsmarine during World War II.

She returned to active duty in the 30th U-boat Flotilla on 1 May 1942, after having been transported overland and along the Danube to the Black Sea.

The submarine was powered by two MWM RS 127 S four-stroke, six-cylinder diesel engines of 700 metric horsepower (510 kW; 690 shp) for cruising, two Siemens-Schuckert PG VV 322/36 double-acting electric motors producing a total of 460 metric horsepower (340 kW; 450 shp) for use while submerged.

She also carried out a series of short journeys, one of which took her to the English east coast near The Wash.

The boat sank Carica Milica with a mine 3.5 nmi (6.5 km; 4.0 mi) off the Shipwash Lightship, (southeast of Aldeburgh) on 18 November 1939.

More success came when the submarine sank Battanglia on 23 January 1940 southeast of Farne Island and Gudveig 4.5 nmi (8.3 km; 5.2 mi) east of the Longstone Light vessel (north of Newcastle).

Having left Constanța on 10 June 1943, she returned on the 11th due to a defective exhaust valve, having first re-fuelled at Feodosia.

The first segment was marred when a second sick crew member was transferred to German submarine U-20 (1936).

On 3 February 2008, The Daily Telegraph newspaper reported that U-20 and U-23 had been discovered by Selçuk Kolay, a Turkish marine engineer.

He thinks he is also close to pinpointing U-19, thought to lie more than 1,000 feet (300 m) down, three miles from the Turkish city of Zonguldak.