Diving in Alifu Alifu Atoll

A thila is a small coral pinnacle standing in open water, and North Ari's diving is built from them. Their steep sides plunge to the seafloor and the tide pumps nutrient-rich water past them, so sharks and schooling fish gather on small patches of reef in a lagoon of about 267 square kilometres. Ari is one reef system divided into north and south on paper, so the northern half has no natural border; what defines it is the thila-and-channel style, with current on most of the marquee dives.

Two dives carry the reputation. At Maaya Thila the show starts after sunset: vast numbers of fusiliers arrive on the pinnacle crown to feed and whitetip reef sharks hunt them, in a current that is very changeable, so the crew's call on timing and entry matters. Fish Head, also known as Mushimasmingili Thila, is the grey-reef-shark dive. It is described as a marine protected area about 100 m long, in front of a major channel, and its Dhivehi name is that of the small brown fusilier schooling there. Published depths differ: one account gives the top of the reef at 8 m and a maximum of 42 m, another about 10 m down to 35 m. Moofushi, at Bojahamadi, is a reef-manta cleaning station on a plateau about 14 m deep where five or six mantas are common. When the current runs hard, the Fesdu trawler wreck is the change of pace, and Hafusa Thila is the deep option for divers who want a plan and the concentration to match.

Hammerhead Point, Madivaru Corner and the Rasdhoo Channel dives belong to Rasdhoo Atoll, northeast of Ari, and share itineraries with North Ari. Scalloped hammerheads are reported resident at Madivaru Corner all year, on an early-morning blue-water dive off the outer wall. Back in North Ari, grey reef and whitetip sharks, reef mantas, eagle rays and humphead wrasse are the regular cast, and sharks are protected across all Maldivian waters.

From Malé it is a 30-minute seaplane flight or about an hour by speedboat; a local ferry takes up to six hours. Divers reach the atoll's sites in three ways. Resort dive shops run boats to the marquee thilas, and the atoll is narrow enough that most resorts reach the best of them; the resort shops at the Rasdhoo end also run trips into North Ari. Some divers stay on local islands such as Himandhoo, Ferudhoo and Rasdhoo and book dives there, and Thoddoo, Ukulhas and Mathiveri are other local-island bases. Liveaboards cover the atoll as part of a wider route.

Current decides who should come. Strong currents on the thilas and in the channels make many North Ari sites suitable only for more advanced divers, and in front of the Fish Head channel the tides can be raging, so a guide may suggest a descent or ascent line. Sheltered walls and reefs and the resorts' own house reefs are the softer option. The Fesdu bow sits right at the recreational depth limit; send a marker buoy up before surfacing at Hafusa. Water stays between 25 and 30 C all year.

December to April is the preferred window, drier with calmer seas. May to November is wetter and rougher, and the changeover between monsoons is the least favourable stretch. Reef mantas are generally reported on the western side of an atoll in the dry months and the eastern side in the wet months, though that pattern is unconfirmed for North Ari's own stations, so ask the operator where they are working that week.