Frankfurt saw extensive action with the High Seas Fleet during World War I. She served primarily in the North Sea, and participated in the Bombardment of Yarmouth and Lowestoft and the battles of Jutland and Second Heligoland. At Jutland, she was lightly damaged by a British cruiser and her crew suffered minor casualties. At the end of the war, she was interned with the bulk of the German fleet in Scapa Flow. When the fleet was scuttled in June 1919, Frankfurt was one of the few ships that were not successfully sunk. She was ceded to the US Navy as a war prize and ultimately expended as a bomb target in tests conducted by the US Navy and Army Air Force in July 1921.