423 Maritime Helicopter Squadron (French: 423e Escadron d'hélicoptères maritimes) is a unit of the Canadian Forces under Royal Canadian Air Force. It currently operates the Sikorsky CH-124 Sea King from CFB Shearwater in Nova Scotia, Canada.
No. 423 Squadron RCAF was a World War II unit of the Royal Canadian Air Force. Formed in 1942 in Oban, Argyll, Scotland for General Reconnaissance duties, it later moved to Castle Archdale, Northern Ireland where it flew Sunderland flying boat patrol bombers. It changed to a transport role in 1945 and was disbanded later that year. Re-formed in 1953 at RCAF Station St Hubert (now Montréal/Saint-Hubert Airport) flying the CF-100 in a continental defence role, it was transferred to RCAF Station Grostenquin in 1957 where it replaced No. 416 Squadron which flew Sabres. The squadron was again disbanded in 1962 when the RCAF's CF-100s were removed from service. In 1974, it was re-formed a final time as No. 423 Anti-Submarine Squadron. In 1995 its name was changed to 423 Maritime Helicopter Squadron. It flies CH-124 Sea King helicopters.