On 20 July 1942, he assumed command of the "Adrias", a Hunt-class destroyer, at Newcastle, United Kingdom. With her, he undertook convoy escort duties in the Mediterranean Sea from January 1943, during which the ship sunk two German U-boats. "Adrias" also covered the Sicily landings in July, and on 10 September she represented Greece in the Allied flotilla that accepted the surrender of the Italian Navy's battle-fleet. Toumbas' finest hour came on 22 October 1943, during the naval operations of the Dodecanese Campaign, when "Adrias" struck a sea mine and lost her entire bow. After makeshift repairs, Toumbas led the ship back to Egypt, arriving at Alexandria on 6 December. In April 1944, he took part in the violent suppression of the pro-leftist Navy mutiny, leading one of the boarding detachments.