U-54 may refer to one of the following German submarines:
, a Type U 51 submarine launched in 1916 and that served in the First World War until surrendered 24 November 1918; broken up at Taranto in May 1919 During the First World War, Germany also had these submarines with similar names: , a Type UB III submarine launched in 1917 and disappeared after 1 March 1918 , a Type UC II submarine launched in 1916 and scuttled on 28 October 1918 , a Type VIIB submarine that served in the Second World War until she went missing after 20 February 1940