List of successful U-boats

List of successful U-boats contains lists of the most successful German U-boats in the two World Wars based on total tonnage.

World War I
This list contains the 5 most successful German U-boats during the First World War based on total tonnage. Only sunk commercial vessels are included, not military (warships) nor damaged ships.

World War II
This list contains the 10 most successful German U-boats during the Second World War based on total tonnage. Both commercial and military vessels (warships) are included but only sunk ships are included, not damaged ships.