The best channels for diving in the Maldives with reef sharks are at - Lhaviyani, North and South Male, Vaavu, Meemu, Laamu and Gaafu (probably the best). Elsewhere the channels are too deep to dive.
The best areas for whale shark encounters are Ari Atoll, and Gaafu and Thaa atolls in the south. For mantas, the best locations are Ari, Addu, North Male, Haa Alifu and Haa Daalu, and Baa Atoll. For Hammerheads, plan a visit to Rasdhoo Atoll in North Ari, or Fotteyo Kandu at Veevu Atoll. Thresher sharks and tiger sharks can be found at Foahmulah Island all year round.
Ari Atoll - Although there are many Maldivian atolls where you can encounter pelagics and big schools of fish, Ari Atoll may be the place with the greatest reliability. Passing big fish such as whale sharks, mantas, hammerheads and eagle rays are frequently seen, as well as large residents like the Napoleon wrasse, grey reef and white tip sharks, and large schools of blacktail barracuda and batfish.
Vaavu Atoll in the Southern Atolls, features deep channels with nutrient-rich, fast-flowing currents. At any time of year you will be treated to encounters with schooling reef sharks as well several different shark species including the occasional hammerhead. The area boasts Fotteyo Kandu.
The recommended months for confirmed liveaboard departures are from November to May but the Maldives scuba diving holiday season runs all year round. If you wish to come outside of November to May it may be more difficult to find a departure date that suits you.
Water temperature are fairly constant throughout the year at 26-29°C, except in the far south where the water temperature can drop to 24°C during the northeast monsoon.