SM UC-3 was a German Type UC I minelayer submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. The U-boat had been ordered by November 1914 and was launched on 28 May 1915. She was commissioned into the German Imperial Navy on 1 June 1915 as UC-3. Mines laid by UC-3 in her 29 patrols were credited with sinking 22 ships and damaging 2 others. UC-3 was caught in a net, detected by hydrophone, and sunk on 23 April 1916 or mined and sunk on 27 May 1916.