French Submarines at Cherbourg Caption: From right to left: ex-German U-151 ex-mercantile OLDENBURG 1917-21, THERMIDOR 1907-20, and FRUCTIDOR 1909-22.

 U-151 was originally one of seven Deutschland class U-boats designed to carry cargo between the United States and Germany in 1916. Five of the submarine freighters were converted into long-range cruiser U-boats (U-kreuzers) equipped with two 15 cm (5.9 in) SK L/45 deck guns, including U-151 which was originally to have been named Oldenburg. The Type U 151 class were the largest U-boats of World War I.

On 25 May 1918 she stopped three American schooners off Virginia, took their crews prisoner, and sank the three ships by gunfire.

On 2 June, known to some historians as "Black Sunday", U-151 sank six American ships and damaged one off the coast of New Jersey in the space of a few hours. U-151 returned to Kiel on 20 July 1918 after a 94-day cruise in which she had covered a distance of 10,915 nmi (20,215 km; 12,561 mi). Her commander reported that she had sunk 23 ships totalling 61,000 tons and had laid mines responsible for the sinking of another four vessels.

At the end of the war U-151 surrendered to France at Cherbourg. The French Navy sank her as a target on 7 June 1921.