SM UB-115 was a German Type UB III submarine or U-boat in the German Imperial Navy () during World War I. She was commissioned into the German Imperial Navy on 28 May 1918 as SM UB-115. She was the only German submarine commissioned with the number 115. UB-115 was sunk by British warships, including HMS Ouse and HMS Star, and the rigid airship R29 at using depth charges and aerial bombs.