U-156 was a German submarine, or U-boat, that operated during World War I. Commissioned in 1917, it was part of the Imperial German Navy and primarily engaged in naval warfare against Allied shipping. U-156 was notable for its long-range capabilities and was equipped with torpedoes and deck guns. The submarine completed several patrols in the Atlantic Ocean and was involved in various attacks on merchant vessels. Ultimately, U-156 was sunk in 1918, marking the end of its operational history. Its service reflects the strategic importance of submarines in naval conflicts during the war.