A vital part of the Royal Norwegian Navy, "Harald Haarfagre" performed ordinary duties until she was considered "unfit for war" in the mid-1930s and disarmed. After the German invasion of Norway, she was seized by the Germans and rebuilt as a floating flak battery under the name Thetis. After the war "Harald Haarfagre" was used briefly as a floating barracks, and for transporting German POWs, before she was sold for scrapping in 1948.