SM U-80 was one of the 329 submarines serving in the Imperial German Navy in World War I.U-80 was engaged in the naval warfare and took part in the First Battle of the Atlantic. U-80 is credited for sinking the Laurentic, the 24th largest ship sunk in World War I by uboats, at 14,892 GRT. She struck two mines laid by U-80 off Malin Head, and sank within one hour. She went down with 345 casualties, and 35 tons of gold ingots. U-80 is also credited with damaging the 6th largest ship, the Celtic, at 30,904 GRT, 15 February 1917 at 53°57′N 04°40′W / 53.950°N 4.667°W. Celtic would be torpedoed later in the war by UB-77, but was beached and later salvaged.