On the night of 13–14 December, "Köln" was attacked by British bombers in Oslofjord; several near misses caused damage to her propulsion system that required repair in Germany. She departed Norway on 23 January 1945 in company with "Admiral Hipper" and a destroyer, and arrived in Kiel on 8 February. She then proceeded to Wilhelmshaven, where she was again attacked by Allied bombers repeatedly. On 30 March, B-24 Liberators from the Eighth Air Force attacked the harbor; "Köln" was hit and sank on an even keel. Since her guns remained above water, the ship was used as an artillery battery to defend the city from advancing Allied forces. She served in this capacity until the end of the war in May. She was partially dismantled "in situ" after the end of the war, and finally raised in 1956 for scrapping.