After five years of operational U-boat service, including 15 war-patrols and over 600 days at sea, Lüth took command of 22nd U-boat Flotilla stationed at Gotenhafen in January 1944. This was a training unit for U-boat commanders. In July 1944 he took command of the 1st Department of the Naval Academy Mürwik in Flensburg. He was promoted to "Fregattenkapitän" (commander) on 1 August 1944 and became the commander of the entire academy in September. He was promoted to "Kapitän zur See" (captain) on 1 September 1944.