Birka was a German passenger ship built in 1937. She was requisitioned by the Kriegsmarine during the Second World War for use as a hospital ship. She struck a mine and sank in 1943.

The ship was 73.23 metres (240 ft 3 in) long, with a beam of 10.39 metres (34 ft 1 in) and a depth of 3.71 metres (12 ft 2 in). She was powered by a 4-cylinder compound steam engine, which had 2 cylinders each of 37 centimetres (14+9⁄16 in) and 2 cylinders each of 80 centimetres (31+1⁄2 in) diameter by 80 centimetres (31+1⁄2 in) stroke. The engine was built by Flensburger Schiffbau-Gesellschaft, Flensburg, Germany. It was rated at 184nhp and drove a single screw propeller. She was assessed at 1,000 GRT, 508 NRT.^[1]

Birka was built by Flensburger Schiffbau-Gesellschaft for Mathies Reederei KG, Hamburg, Germany.^[1] She was launched on 23 June 1937.^[2] Her port of registry was Hamburrg and the Code Letters DJUF were allocated.^[1] On 24 November 1937, she ran aground off the coast of Sweden and was severely damaged.^[3] She was refloated the next day and taken in to Stockholm for repairs.^[4]

On 5 September 1940, Birka was requisitioned by the Kriegsmarine for use as a hospital ship.^[5] Allocated to 5 Vorpostengruppe and designated as "Schiff 8",^[6] she served in Norwegian waters. On 1 June 1943, she struck a mine and sank in the Altafjord with the loss of 115 lives.^[5] The mine had been laid on 6 May by the Soviet submarine L-22.^[7] The Stockholms-Tidningen claimed that Birka had been used to carry troops and munitions from Trondheim to Kirkenes in violation of her status as a hospital ship.^[8]