SM UB-68 was a German Type UB III submarine or U-boat in the German Imperial Navy () during World War I. The U-boat was ordered on 20 May 1916. She was commissioned into the German Imperial Navy on 5 October 1917 as SM UB-68. The submarine conducted five patrols and sank five ships during the war. Under the command of Karl Dönitz, on 4 October 1918 UB-68 encountered technical problems and had to surface where she was shelled until sinking at . There was one dead and thirty-three survivors. Other sources name the British warships involved in the sinking of UB-68 as HMS Snapdragon and HMS Cradosin, and claim four crew members died in the event.