St Mary's Airport or Isles of Scilly Airport (IATA: ISC, ICAO: EGHE) is an airport located 1 nautical mile (1.9 km; 1.2 mi) east of Hugh Town on St Mary's in the Isles of Scilly, to the south west of Cornwall, UK. It is the only fixed-wing airport serving the Isles of Scilly, handling most air traffic to and from the Islands. (There is a heliport on the island of Tresco.) The airport is owned by the Duchy of Cornwall and currently is operated by the Council of the Isles of Scilly.

On 15 September 1937, Olley Air Service's subsidiary Channel Air Ferries started the first scheduled service between Land's End and St Mary's, flying de Havilland Dragons. Initially, however, the planes landed on the St Mary's golf course. St Mary's Airport was first opened in August 1939, after being converted from High Cross Farm.

In 1938, Great Western and Southern Airlines took over Olley Air Service and Channel Air Ferries. It continued the service throughout World War II, during which it replaced the Dragons with de Havilland Dragon Rapides. On 1 February 1947 this operation was taken over by British European Airways (BEA). In August 1949 a control tower and a passenger waiting room were completed at St Mary's.

On 2 May 1964, BEA replaced its Dragon Rapides on the Land's End route with a single Sikorsky S-61 helicopter, operated by BEA Helicopters. From 1 September 1964 the route was to the new Penzance Heliport. BEA Helicopters later became British Airways Helicopters, and subsequently British International Helicopters. A second helicopter was eventually added to the service in the summers.

Mayflower Air Services started services to the airport in 1961; this operation was taken over by Scillonian Air Services in 1963, itself taken over by British Westpoint Airlines in 1964. Scillonia Airways operated services to the airport from 1966 to 1970. Westward Airways, not to be confused with Westward Airways (Lands End), operated services from 1967 to 1970. Brymon Airways operated services from June 1972 to March 1991, initially with Britten-Norman Islander aircraft, and two years later, de Havilland Canada DHC-6 Twin Otters.

In 1975, a new terminal was opened by the then Prime Minister Harold Wilson.

In 1984, Isles of Scilly Skybus started flights to St Mary's from Land's End, initially freight and charter. Scheduled services started on 1 April 1987, flying Islanders and, later, Twin Otters.

The current 600-metre (2,000 ft) asphalt runway, 15/33, was built in 1991.

After being in operation for 48 years, the helicopter service between St Mary's and the mainland UK ceased operations in October 2012, leaving Skybus as the sole remaining air link for the Isles of Scilly. A helicopter service operated between Land's End Airport and St. Mary's in summer 2018.

In May 2013, the Isles of Scilly Steamship Company and the Council of the Isles of Scilly submitted a joint bid for finance from the European Regional Development Fund for improvements to the terminal, new lighting and navigational systems and runway resurfacing, together with runway resurfacing at Land's End Airport. In May 2014, the European Commission gave its approval. The upgrades at St Mary's are expected to cost £6.5 million.

The terminal at the airport is open all year round whilst the airport is in operation. It has a buffet, toilets, as well as access to wheelchairs upon request. The airport is used as a landing area for some emergency services such as the HM Coastguard Search and Rescue Aircraft (based out of Newquay Airport) and the Cornwall Air Ambulance, as well as being the administrative base for the Isles of Scilly Fire and Rescue Service.

A public footpath passes within a few metres of the southern end of the runway; it is closed by warning lights and bells a few minutes before a take-off or landing is due.

As of July 2020, St Mary's Airport has regular service to the following destinations:

Airlines	Destinations
Isles of Scilly Skybus	Land's End Seasonal: Exeter, Newquay
Starspeed	Penzance

Traffic statistics at St Mary's Airport

Year	Passengers	Passengers % change	Aircraft	Aircraft % change	Freight (tonnes)	Freight % change
2021	72,291		8,935		95
2022	86,846	20.1	10,381	16.2	97	2.1
2023	69,404	20.1	8,849	14.8	111	14.4

Busiest routes to and from St Mary's Airport (2023)

Rank	Airport	Total passengers	Change 2022/23
1	Exeter	8,063	31.8%
2	Newquay	1,530	27.3%
3	Land's End	n/a
4	Penzance	n/a

• On 16 July 1983, a British Airways Helicopters passenger helicopter, on a scheduled flight from Penzance Heliport, crashed into the sea 2 NM (3.7 km; 2.3 mi) short of St Mary's Airport. 19 passengers and one crew member were killed; there were six survivors.

• Official website