Australia
Osprey Reef is an isolated submerged atoll in the Coral Sea northeast of Queensland, rising from a seamount and known among divers for its steep walls and shark sightings.
Osprey Reef sits roughly 110 km from the northern Great Barrier Reef. It is an oval atoll measuring about 25 by 12 km, with a shallow central lagoon and vertical outer walls plunging to around 2,000 m depth. Protected within the Coral Sea Commonwealth Marine Reserve, it is noted for large soft corals, shark encounters, and an isolated dwarf population of Nautilus pompilius.