 Reactivated at the start of World War I, she initially laid both defensive and offensive mine fields in the North and Baltic Seas.She was permanently transferred to the Baltic in 1916, and the following year she supported Operation Albion, the conquest of the Gulf of Riga.After Germany's defeat, "Nautilus" was demilitarized and used as a hulk from 1921 to 1928 before being sold for scrap and broken up in Copenhagen.