U-70 may refer to one of the following German submarines:
- SM U-70, a Type U 66 submarine launched in 1915 and that served in the First World War until surrendered on 20 November 1918; broken up at Bo'ness in 1920–21
- During the First World War, Germany also had these submarines with similar names:
- SM UB-70, a Type UB III submarine launched in 1917 and disappeared after 5 May 1918
- SM UC-70, a Type UC II submarine launched in 1916 and sunk on 28 August 1918
- During the First World War, Germany also had these submarines with similar names:
- German submarine U-70 (1940), a Type VIIC submarine that served in the Second World War until sunk on 7 March 1941
This article includes a list of ships with the same or similar names. If an internal link for a specific ship led you here, you may wish to change the link to point directly to the intended ship article, if one exists.