The IIIA and IIIB saw limited service towards the end of the war, with some IIIBs being used for mine-spotting duty from the seaplane station at Westgate-on-Sea. The IIIC entered service in November 1918, but did not carry out any combat patrols owing to the Armistice ending hostilities with Germany. Seven IIICs were deployed to Arkhangelsk in 1919 by the seaplane tender HMS Pegasus in support of the North Russian Expeditionary Force. They were used to carry out bombing attacks against Bolshevik shipping and rail communications.
The IIID was operated by the Royal Air Force and Fleet Air Arm as well as the Naval Aviation of Portugal (11 aircraft) and the air forces of Australia.
Australia received six IIIDs, the first being delivered in August 1921. In 1924, the third of the Australian IIIDs, designated ANA.3 (or Australian Naval Aircraft No. 3), flown by Stanley Goble (later Air Vice Marshal) and Ivor McIntyre was awarded the Britannia Trophy by the Royal Aero Club for circumnavigating Australia in 44 days. The IIID remained in Australian service until 1928.
Portugal ordered its first IIIDs in 1921. Its first aircraft, modified as the F.400 and named "Lusitânia", was used for an attempt to fly across the South Atlantic and demonstrate the new aerial navigation system devised by Gago Coutinho, the navigator. The voyage started on 30 March 1922 (Flyers Day in Portugal), stopping at Las Palmas, São Vicente, Cape Verde and achieving the main navigation goal of Saint Peter and Paul Rocks, where it was lost during refuel. The journey was finished using another two standard aircraft (the second of which was immediately lost in the sea), completing the first aerial crossing of the South Atlantic, 72 days after their departure from Lisbon. The last aircraft, "Santa Cruz", is currently displayed at the Museu de Marinha, in Portugal.
The IIID entered Fleet Air Arm Service in 1924, operating from shore bases, aircraft carriers and floats until replaced by the IIIF in 1930. The RAF Cape Flight used four IIIDs to carry out a long distance formation flight from Cairo to Cape Town and back in 1926, the first long range formation flight by the RAF and the first RAF flight to South Africa. Fleet Air Arm IIIDs were used to defend British interests in Shanghai against rebel Chinese forces in 1927.
The IIIF entered service with the RAF in Egypt and with Fleet Air Arm Catapult flights in 1927, and with the Royal New Zealand Air Force shortly after. The RAF used the IIIF to equip general-purpose squadrons in Egypt, Sudan, Aden and Jordan, where its ability to operate from both wheels and floats proved useful, while the contemporary Westland Wapiti carried out similar roles in Iraq and India. As such IIIFs were used for colonial policing as well as taking part in further long distance flights. The RAF also used the IIIF to finally replace the Airco DH.9A in the home based Day-Bomber role, and, in the absence of sufficient long range flying boats for maritime patrol duties by 202 Squadron from Hal Far Malta.
In the Fleet Air Arm, the IIIF replaced the IIID as a spotter-reconnaissance aircraft, operating on floats from the Royal Navy's cruisers and battleships, and with wheels, from the aircraft carriers HMS Furious, Eagle, Courageous, Glorious and Hermes.
The IIIF remained in front line service well into the 1930s, with the last front line RAF squadron, 202 Squadron, re-equipping with Supermarine Scapas in August 1935, and the final front line Fleet Air Arm squadron, 822 Squadron retained the IIIF until 1936. The IIIF remained in use in second line roles, and despite being declared obsolete in 1940, some were still in use as target tugs as late as 1941.