At the start of the Second World War, there were 26 RAF squadrons operating the Anson I; ten with Coastal Command and 16 with Bomber Command. However, by this time, the Anson was obsolete in the roles of bombing and coastal patrol.
Limited numbers of Ansons continued to serve in operational roles such as coastal patrols and air/sea rescue after the outbreak of World War II. However, the aircraft were used primarily to train pilots for flying multi-engine bombers such as the Avro Lancaster. The Anson was also used to train the other members of a bomber air crew, such as navigators, wireless operators, bomb aimers and air gunners. Postwar, the Anson continued in the training role and light transport roles. The last Ansons were withdrawn from RAF service with communications units on 28 June 1968.
The Royal Australian Air Force operated 1,028 Ansons, mainly Mk Is, until 1955. The Royal Canadian Air Force and Royal Canadian Navy operated Ansons until 1952. The USAAF employed 50 Canadian-built Ansons, designated as the AT-20.
The Royal New Zealand Air Force operated 23 Ansons as navigation trainers in the Second World War, (alongside the more numerous Airspeed Oxford), and acquired more Ansons as communication aircraft immediately after the war. A preserved navigation trainer is in the Royal New Zealand Air Force Museum at Wigram.
The Egyptian Air Force operated Ansons in communications and VIP duties. A specially outfitted Anson was gifted to the then King by the Royal Air Force. The Royal Afghan Air Force obtained 13 Anson 18 aircraft for various duties from 1948. These aircraft survived through 1972.