SM U-140 was a Type U 139 submarine that served in the Imperial German Navy in World War I.U-140 was engaged in the naval warfare and took part in the First Battle of the Atlantic.
After the end of World War I, U-140 surrendered to the United States, which used her for testing. Finally, the United States Navy destroyer sank her as a target in the Atlantic Ocean off Cape Charles, Virginia, on 22 July 1921.
| Date | Name | Nationality | Tonnage[1] | Fate[2] | |
|---|---|---|---|---|---|
| 27 July 1918 | Porto |  Portugal | 1,079 | Sunk | |
| 2 August 1918 | Tokuyama Maru |  Japan | 7,029 | Sunk | |
| 4 August 1918 | O. B. Jennings |  United States | 10,289 | Sunk | |
| 5 August 1918 | Stanley M. Seaman | United States | 1,060 | Sunk | |
| 6 August 1918 | 590 | Sunk | |||
| 6 August 1918 | Merak | United States | 3,024 | Sunk | |
| 21 August 1918 | Diomed |  United Kingdom | 7,523 | Sunk |