The Rasdhoo Channel runs through the southern rim of Rasdhoo Atoll and is the dive that put the island on the dive map. Scalloped hammerhead sharks pass through the channel at depth — typically 30 to 40 metres — in the hour around dawn. Sightings are not guaranteed; on a quiet morning the dive is mostly a deep blue-water cruise. On a good morning a school of forty or fifty hammerheads will move past at depth.
The dive is technical: deep, current-dependent, and requires AOWD certification and ideally Nitrox. The dive boats leave around 5 AM. Sightings are most reliable from January through April, when the channel water is coolest. Bring layers — the early morning panga ride to the dive site is colder than you would expect.