  Masteyra Island Location in Antarctica | |
| Geography | |
|---|---|
| Location | Antarctica |
| Coordinates | 64°22′32″S 63°41′47″W / 64.37556°S 63.69639°W |
| Archipelago | Palmer Archipelago |
| Length | 700 m (2300 ft) |
| Width | 200 m (700 ft) |
| Administration | |
| Administered under the Antarctic Treaty System | |
| Demographics | |
| Population | Uninhabited |
Masteyra Island (Bulgarian: остров Мастейра, romanized: ostrov Masteyra, IPA: [ˈɔstrof mɐˈstɛjrɐ]) is a rocky island 700 m long in east-west direction and 200 m wide lying in Perrier Bay on the northwest coast of Anvers Island in the Palmer Archipelago, Antarctica. It is separated from Anvers Island to the east-southeast by a 1.13 km wide passage.
The island is named after the ancient Thracian settlement and fortress of Masteyra in Southern Bulgaria.