German submarine U-25

U-25 may refer to one of the following German submarines:


 * SMU U-25, was a Type U 23 submarine launched in 1913 and that served in the First World War until surrendered on 23 February 1919
 * During the First World War, Germany also had these submarines with similar names:
 * SMU UB-25, a Type UB II submarine launched in 1915 and surrendered on 26 November 1918
 * SMU UC-25, a Type UC II submarine launched in 1916 and scuttled on 28 October 1918
 * GS U-25 (1936), a Type IA submarine that served in the Second World War until lost in August 1940
 * GS U-25 (S174), a Type 206 submarine of the Bundesmarine that was launched in 1974; no longer in service