Masirah or Mazeira Island (Arabic: مصيرة‎) is an island off the East coast of Oman, 95 km long north-south, between 12 and 14 km wide, with an area of about 649 km², and a population estimated at 12,000 in 12 villages mainly in the north of the island (9,292 as of the census of 2003, of which were 2,311 foreigners). Administratively, it forms one of the eleven provinces (Arabic: ولاية, plural ولايات, transliteration: wilayah, plural wilayat) of the Ash Sharqiyah Region. The principal village is Ras-Hilf in the northern part of the island. It contains a Royal Air Force of Oman air base and a fish factory, as well as a few small towns. Previously, the BBC had a relay facility consisting of both HF and MF broadcasting transmitters stationed there. Most of the island's interior is deserted, with access to the island only possible by a small ferry for cars or by Royal Air Force of Oman Airbus A320 or Lockheed C-130 Hercules flights.
The main industries are fishing and traditional textile manufacturing. Formerly, traditional ship building was important.