The A-class submarines were a class of three vessels of German design built by the Krupp Germania naval shipyard in Kiel, Germany from 1913 to 1914 and deployed by the Royal Norwegian Navy.
The Norwegian government purchased four submarines that were almost completed in 1913 and received three of these before World War I. The fourth, A-5, was seized by German authorities at the outbreak of war and commissioned as SM UA. It was used for coastal protection and from 1916 as a training vessel in the Baltic Sea.
A-2 (2 March 1914 – 9 April 1940) Attacked and severely damaged by the two German R boatminesweepersR-22 and R-23 off the Vallø peninsula near Tønsberg in the Oslofjord on 9 April 1940. Her crew was captured and she drifted ashore at Vallø, a total wreck.
A-3 (1914 – 16 April 1940) Scuttled by own crew in Verkbukta at Tønsberg on 16 April 1940
A-4 (1914 – 16 April 1940) Scuttled by own crew in Verkbukta at Tønsberg on 16 April 1940