RNAS Portland (ICAO: EGDP) was an air station of the Royal Navy, situated at the Isle of Portland, Dorset, England. It was established in 1917 on the western edge of Portland Harbour, close to the naval dockyard. From 1959 the station shared the name HMS Osprey with the anti-submarine shore-based establishment located at East Weares, which used the air station's helicopters for research and development in anti-submarine techniques. The establishment originally operated at Portland between 1924 and 1941, and was recommissioned there in 1946, until its closure in 1995. RNAS Portland remained operational until it too closed in 1999.