In five patrols in her six-month career, "UB-45" sank four ships of . In early November 1916, "UB-45" was departing from the base at Varna, Bulgaria, when the U-boat struck a mine and sank rapidly. Fifteen of the twenty men on board were killed in the attack; one of the five crewmen rescued from "UB-45" later died from his injuries. "UB-45"s wreck was located and raised by the Bulgarian Navy in the 1930s with an eye toward rebuilding the submarine. Engineers from AG Weser determined that restoration of the submarine was feasible, but this was never accomplished. Remains recovered from the wreck were buried in Varna after a funeral procession through town in November 1938.