U 25
U 25 designated
- several German submarines:
- SM U 25 (1914–1919), a submarine of the Imperial Navy during the First World War
- U 25 (Kriegsmarine) (1936–1940), a submarine of the German Wehrmacht in World War II
- U 25 (Bundeswehr) (1974–2008), a submarine of the German Bundeswehr
- In the area of unemployment benefit II, U25 means unemployed adults living with their parents who are not yet 25 years old.