Top 10 dive sites

01 Wreck of the Madeirense, Porto Santo, Madeira

The scene: Even on the 10-minute flight from Funchal, Madeira's capital, to this golden fleck of an island 28 miles to the north-east, I can tell the diving will be spectacular. Our small plane flies the entire length of a five and a half mile stretch of virgin sand flanked by mirror-calm turquoise ocean, more like the Caribbean than the Atlantic. In high summer, Porto Santo morphs into a party island, but in spring I'm able to enjoy clear blue skies and bright sunshine without encountering another soul. It is unnervingly quiet as I board the rigid inflatable boat (RIB) with Pedro Koch, my divemaster from Rhea Dive, and I'm the only visiting diver completing a gentle orientation dive at a shallow site called Cemitério das Ancoras (Graveyard of Anchors) in preparation for the deep wreck dive that afternoon. Because of the technical knowledge required, not to mention the increased air consumption at depth, this dive isn't suitable for beginners and is recommended for PADI Advanced Open Water divers or their equivalent and above.

The site: Lying upright on sand at a depth of 111ft, the Madeirense is just over a mile offshore and easily reached from the harbour. The 230ft-long vessel was deliberately sunk in 2000 to create an artificial reef for divers. All manner of large fish come to feed nearby, as well as the odd whale, while the wreck is a sanctuary for moray eels and other denizens. The Madeirense may be the best-known dive site on the island but it is not the only one. Around 20 others are listed by Rhea Dive, including numerous reefs and a foray among ancient cannon.

The experience: So clear is the water, I can make out the entire outline of the wreck from the RIB 82ft above its coral-encrusted handrail. Visibility is typically 100ft, though it can reach a disorientating 200ft, making it feel as if you are diving in air. Hauling my way hand-over-hand down the shotline — used by divers to move between the surface and the dive site — I'm immediately greeted by Beiçolas (meaning 'Big Lips'), a friendly three foot-long grouper that follows divers around and lets them pat him like a dog. The deep indigo waters surrounding the Madeirense fizz with marine life. I pick out the distinctive shape of big ocean tuna, silvery trevally jack, snapper the size of dinner plates and the needle-like profile of a lone barracuda, while the vessel's superstructure is obscured by shimmering clouds of reef fish and patrolling striped pargo. Penetration of the wreck is discouraged for safety reasons, but we circle it slowly at deck level, observing Beiçolas, then descend for another complete circuit at seabed level to watch red mullet sifting the sand while looking out for the telltale outline of a half-buried stingray. The rare combination of dramatic water clarity, high-energy marine life and the challenge of depth, all within easy access, makes the experience pretty special. Though it's important to remember this is raw Atlantic diving, requiring a 7mm semi-dry in summer and a drysuit in winter.

How to do it: Take the ferry from Funchal for £36 return or fly from £126 return. Hotel Vila Baleira has doubles from about £118 per night, B&B. Rhea Dive, based at the hotel, offers single dives from £27 and four-dive packages from £100, including tanks and weights. portosantoline.com  sata.pt  vilabaleira.com  rheadive.com

02 USS Kittiwake, Cayman Islands

The scene: Warm clear water is the draw here, making all three of these Caribbean islands ideal for learning. For experienced divers, Grand Cayman has dozens of wrecks, reefs and walls including Tarpon Alley, patrolled by hundreds of powerful game fish. The best-known shallow dive is at Stingray City, where up to 100 rays gather like friendly puppies around the dive boats to accompany divers and snorkellers. Little Cayman has around 50 sites including the spectacular Bloody Bay Wall, beginning at 20ft and plunging straight down to 6,500ft.

The site: In January 2011, Grand Cayman acquired a brand new adventure playground: the decommissioned USS Kittiwake, a 251ft submarine rescue vessel was deliberately sunk in 65ft of water to create an artificial reef. Located in the sheltered area of Grand Cayman, at the northern end of Seven Mile Beach, the superstructure lies just 16ft beneath the surface.

The experience: Even snorkellers can swim over the main decks and bridge, peering down the smoke stack to the engine room. Large apertures cut in the hull allow divers to enter and leave safely. Just eight months since its sinking and the Kittiwake is already overgrown with thick algae, the equivalent of foie gras for fish — hence the abundant shoals. Outside the wreck, horse-eye jack cruise the periphery while, inside, the vessel's engines and chains provide hiding places for squirrelfish, arrow crabs and banded coral shrimp. On the seabed is an eel garden — dozens of the creatures buried in the sand, writhing like fronds of grass — and, in midwater, a barracuda cruises by like a silver missile.

How to do it: Cobalt Coast Resort offers four nights' accommodation, including meals, with three days of diving from £630 per person, based on two sharing. cobaltcoast.com

03 Fairyland, St Lucia

The scene: Though it has a few moderately challenging walls (Anse La Raye, Piton Wall) and a decent wreck (the Lesleen-M), St Lucia is the place to go for languid tropical diving. You can learn on a quiet house reef, then proceed to stride off a boat into tepid, gin-clear water redolent of a giant aquarium.

The site: Located within Soufrière Marine Park where it's forbidden to anchor, fish or touch anything underwater, Fairyland offers Caribbean drift diving at its best. I have dived here six times and got married (once!) on a dive boat idling above this seemingly endless prairie of brain corals, vase sponges, gently swaying gorgonians (fern-like corals), boulders and gulleys flanked by a steep wall on the seaward side and the soaring Piton mountains on the other.

The experience: Despite the aquarium analogy, the water can feel cold here on account of currents that keep the reef clean and the visibility in excess of 130ft on a good day. Then, as you round an underwater cliff or canyon, the water turns lukewarm, the differential creating rippling thermo-clines where cold and warm layers meet — an amazing optical effect. On my first dive, I spot a nurse shark sheltering under a coral shelf, a spotted moray eel and a large lobster. The second is disappointing because the water is murkier, but on our wedding dive, it is startlingly clear again and we see morays, a squat lobster, a rare spotted drum and, best of all, a large bewitching turtle which we follow for minutes.

How to do it: Anse Chastanet Resort offers seven-night Coral Kaleidoscope diving packages from £3,445 for two people sharing, including accommodation, all meals, transfers and 12 dives. ansechastanet.com
 

04 Shark Reef & Yolanda Reef, Ras Mohammed, Egypt

The scene: The Red Sea is where British divers go for a taste of the tropics close to home. So popular is it, stories abound of 40 boats clustered over one wreck and divers climbing into the wrong one on surfacing, such is the chaos of mass tourism underwater. That's why I dived with Sinai Blue at the Four Seasons Resort Sharm El Sheikh, which has exclusive rights to certain dive sites. Yet it is the popular old favourite — Ras Mohammed National Park — that delivers in spite of it all, on a day trip onboard the Four Seasons liveaboard, the Virginia.

The site: Ras Mohammed occupies a slim peninsula 25 miles south of Sharm. Surrounded by pristine coral scrubbed clean by currents, it is suited to experienced divers who can hold their depth and maintain neutral buoyancy while swimming in 'the blue' with no visual reference points.

The experience: I have to fin hard against a very strong current to reach the coral wall of Shark Reef, plunging straight down to 2600ft. Hugging it at 50ft, we glance out into the blue to see hundreds of trevally jack, tuna and a ball of shoaling fish — which may indicate a big predator. Between the two reefs, things are more tranquil but there is marine life aplenty: a moray out in open water, batfish, unicorn fish, a stingray and, well camouflaged off Yolanda Reef, a primeval-looking crocodile fish. We pass several groups of divers, as expected, bemused by the bizarre sight of heaps of lavatory bowls, sinks and tyres dispersed from a wreck which at some point toppled into the abyss.

How to do it: Four Seasons Resort Sharm El Sheikh has doubles from £250 per night, including two dives daily and gear rental. fourseasons.com
 

05 Wreck of the SS Excellent, Gibraltar

The scene: Gibraltar is where I did my formative diving, 93 descents in all. Its military history makes it a wreck diver's dream, though my logbook is also full of bass, conger eels, rays and even seahorses.

The site: Sunk in 1888, the steel-clad steamer lies upside down at 88ft off the harbour. Safe to penetrate, its ribbed interior seems cathedral-like by torchlight.

The experience: Bristling with fan worms and gorgonians, the hull is home to lobsters, gurnard and scorpionfish.

How to do it: Dive Charters has single dives for £65 and eight-dive packages for £310, including equipment hire. The Caleta Hotel has doubles from £135 per person per night, sharing. divegib.gi  caletahotel.com

 
06 Silfra Rift, Iceland

The scene: Iceland's underwater attractions range from a geothermal chimney in a fjord to a sunken oil tanker and encounters with friendly wolf fish.

The site: Divers swim along the submerged crack between the Eurasian and American continental plates. It's extreme drysuit diving in temperatures of 2-4C, with visibility 300ft or more.

The experience: I fin through Silfra's three sections: the 'Hall', the cavernous 'Cathedral' and into the 'Lagoon' — all submerged beneath Thingvellir Lake, fed by icy glacial waters. Bubbles rise from the rock floor as gas escapes from deep within the earth's crust.

How to do it: Dive Iceland offers Silfra day trips from £160. Doubles at the Hotel Reykjavik Centrum start at £85. dive.is  hotelcentrum.is
 

07 Shark Arena, New Providence, Bahamas

The scene: The Bahamas are famous for the Bond wrecks — the freighter where 007 eluded a tiger shark in Never Say Never Again, and the downed Vulcan bomber from Thunderball — and shark feeding. Off Walker's Cay, I've sat in a circle of divers as up to 100 reef and blacktip sharks feed on a 'chumsicle' (frozen offal), then swum among them and stroked their bellies. Off New Providence, I've watched a diver in a chainmail suit proffer fish morsels on a spear and trigger a feeding frenzy, remembering to keep my hands tucked under my armpits to avoid them being mistaken for snapper.

The site: Both of the above operations were stage-managed and ethically questionable, altering the behaviour of wild sharks. A more palatable alternative is offered at the Shark Arena, about nine miles off New Providence — a hugely enjoyable wall dive, given an additional frisson by the divemaster carrying a small bottle of fish blood on his belt and occasionally releasing some of it.

The experience: As we drift hypnotically along the reef in startlingly clear water, a reef shark, well over six feet long, cruises parallel to us then comes in for a closer look — a high-adrenalin encounter. I try to hold on to my divemaster's reassurance that no attack has ever occurred in several years of doing this. The only bump I get is from a large grouper, also joining us. Because of rough seas — not to mention sharks all around you — this is one for confident divers.

How to do it: Stuart Cove has three-night packages, including two days of diving and accommodation, from £210 per person, based on two sharing. A free swim with sharks can be arranged. stuartcove.com
 

08 Lavezzi Marine Park, Corsica

The scene: Corsica and Sardinia have some of the cleanest, clearest waters in the world (160ft-plus visibility). Free-diving contests are often held here, with breath-holding athletes finning into the blue to depths beyond scuba range.

The site: Lavezzi, along with the archipelago of the Maddalena, are two marine parks accessible from Sardinia and Corsica forming a vast protected area. I arrived by fast RIB from Capo Testa, Sardinia, aiming for the abandoned lighthouse east of Bonifacio.

The experience: Touching bottom at 100ft, I was immediately surrounded by six black grouper weighing 90lbs each, nudging me and curiously eyeing up my buddy. Nearby Grouper Reef is home to a colony of these territorial leviathans.

How to do it: Nautilus Diving Centre, in Palau, has seven nights' accommodation plus eight dives from £370 per person sharing. divesardegna.com
 

09 Stingray Rock, Aldermen Islands, New Zealand

The scene: The Aldermen Islands, 12 miles off the Coromandel Peninsula, offer superb temperate water diving, with volcanic pinnacles and kelp forests.

The site: Suitable for advanced divers, pinnacle Stingray Rock's steep sides are covered with sponges and sea squirts.

The experience: The boat anchors at the top of the 'pin' and divers circle the boot-shaped rock, descending to a depth of 100ft and staying close to the wall. Pink maomao, butterfly perch, demoiselles and trevally jack school out in the blue while occasional kingfish, shark or marlin make an appearance. A large population of stingrays feeds here.

How to do it: Delphinus Divers does two-dive trips to the Aldermen from £107, including equipment rental. Tairua Shores Motel offers chalet accommodation from around £50 per night. tairuadive.co.nz
 

10 Le Lac, Tignes, France

The scene: People come to the Haute Savoie Alps to ski; but in the resort of Tignes, diving beneath the ice is offered as a diversion, even for complete beginners.

The site: Look out across the frozen lake and you'll see an area cordoned off with orange netting. Within it are several square holes cut in the ice.

The experience: In a drysuit with screw-on gloves and a full face mask, so no skin is exposed, I slip through one of the holes. Throughout the dive, I am on a short tether attached via a ring to a guideline running the length of the site. Escorted by an expert, I remain near the ice ceiling, exploring its bubbles and fissures in a lifeless world illuminated by an eerie greenish glow.

How to do it: Ice Diving School of Tignes offers dives from around £70. Consult ski operators for accommodation choices. tignesplongee.com

Published in the Mar/Apr 2012 issue of National Geographic Traveller (UK)