Would you like to be under the sea? Even if diving with sharks isn't your thing, there are underwater cocktails bars. Go ahead, dive in!
1. Diving with great whites, Gansbaai, South Africa
Everyone knows how the Jaws theme music goes. Diving with great white sharks is up there with base-jumping in the adrenaline top 10, and Gansbaai in the Southern Cape is the ideal place to swim with the big fish. Fortunately, there's an aluminium cage – or for the brave, a clear plastic tube – between you and the ocean's greatest killing machines. Numerous companies offer dives in Gansbaai's 'Shark Alley', but look for operators who invest their profits back into shark conservation. The Shark Lady, aka Kim Maclean, pioneered shark diving at Gansbaai; peak shark season runs from May to October.
2. Getting married underwater in Trang, Thailand
If you fancy making a splash on your wedding day, consider an underwater wedding at Trang in southern Thailand. Every Valentine's Day, dozens of couples don scuba tanks and descend to an altar 12m beneath the Andaman Sea for a full Thai wedding ceremony. Wedding dresses are de rigueur and even the marriage certificate is signed underwater; the ceremony ends with the happy couple releasing one million baby shrimps and a giant clam onto the reef to gain Buddhist merit. Of course, it's tricky saying 'I do' with a regulator in your mouth…
The Trang Underwater Wedding Ceremony runs from 12 to 14 February every year, and brides and grooms must be certified open-water divers.
3. Sleeping with the fishes in Fiji
Travellers with plenty of cowrie shells to spare can swap a night under the stars for a night with the starfish at the sparkling new Poseidon Undersea Resort in the Fiji islands. Suites are housed in futuristic pods on the sea bed, covered by acrylic domes and linked to the surface by a high-speed elevator. There's even a private submarine that guests can pilot around the lagoon. It's all very James Bond, and the prices would make a supervillain wince.
There's a long waiting list for rooms at Poseidon Undersea Resort. If you have to ask the cost, you probably can't afford it.
4. The ultimate fish supper in the Maldives
Taking the heights of luxury to the depths of the ocean, the Conrad Rangali Maldives resort offers every imaginable indulgence, including an eatery at the bottom of the briny. Covered by a curving glass canopy, the Ithaa restaurant floats beneath a curtain of swirling tropical fish, 5m below the surface of the Indian Ocean. Stingrays, groupers and sharks are regular visitors – think of it as an aquarium where the fish get to watch you eat. If you can see past the obvious contradiction, the menu runs to spiced scallops, tuna sashimi and lobster fricassee.
Visit the Conrad Rangali Maldives from December to March for peak underwater visibility.
5. Swimming to your room in the Florida Keys
The only hotel in the world where you have to scuba dive to reception, Jules'Undersea Lodge is housed inside a converted marine laboratory off the coast of Key Largo. Just six people fit inside this futuristic space, which opens directly onto the sea bed through a pressure-balanced wet room. The compact quarters might deter the claustrophobic, but the sea-lab setting is very James Cameron's The Abyss. Rates include meals – delivered from the surface in waterproof containers – as well as unlimited tanks for dives in the lagoon.
Advance bookings are essential for the two bedrooms at Jules' Undersea Lodge, and guests must be certified divers or take a special introductory dive course.
6. Snorkelling with whale sharks, Ningaloo Reef, Australia
Swimming with sharks feels a lot less scary when the sharks in question don't eat meat. Whale sharks grow to more than 12m in length – as long as a doubledecker bus – but these gentle giants live off a diet of microscopic plankton. Whale sharks spook easily and the ideal way to get close is with a mask, snorkel and fins, so the best place to swim with the world's biggest fish is Ningaloo Marine Park on the west coast of Australia. Numerous operators run shark-snorkelling tours from the town of Exmouth in Western Australia.
Whale sharks visit Ningaloo Reef between April and July – at other times, you'll have to make do with manta rays, turtles, dolphins and humpback whales.
7. Submarine cocktails in Eilat, Israel
According to Jules Verne, Captain Nemo frowned on alcohol and anything else associated with the surface of the earth, but the Red Sea Star would still be his kind of bar. Nestling on the seabed off the coast of Eilat, this wacky watering hole offers the rare opportunity to sip a sea breeze cocktail at the bottom of the sea. Okay, so the decor – wobbly windows, starfish lanterns, jellfish chairs – is as tacky as an octopus's tentacles, but you can't fault the views over a coral garden teeming with fish.
Before you jump into your swimming costume, the Red Sea Star is attached to dry land by a 70m pontoon.
8. Wreck diving in Truk Lagoon, Micronesia
The world of wreck diving owes a lot to WWII – whole fleets of warships were sent down to Davy Jones at Coron in the Philippines and in Scapa Flow in Scotland. But nothing compares to wreck diving in the tiny state of Chuuk in Micronesia. The sandy seabed of this coral atoll forms an eerie graveyard for more than 300 Japanese battleships, freighters, submarines and aircraft, sunk in a single devastating American assault in February 1944. However, dive carefully – the wrecks still carry their original cargoes of tanks, ammunition, torpedoes, depth charges and mines.
Continental Micronesia flies from Guam to the tiny airstrip on Weno island four times a week.
9. Freshwater frolics in Lake Malawi
Landlocked Malawi might seem an unlikely destination for a dive trip, but Lake Malawi has hidden depths (ahem). One of the world's top spots for freshwater diving, this African Great Lake is home to at least 1500 species of tropical fish, but significantly, no crocodiles (for some reason, they stick to the rivers feeding the lake). On the southern lakeshore, Monkey Bay is a prime spot to learn to dive: for one thing, the 'pool' training takes place in the warm, current-free waters of the lake.
In the chilled-out traveller centre of Cape Maclear, Gecko Lounge scores highly for its lakeside terrace and boisterous party vibe.
10. Disappear into a blue hole in Mexico
The polar opposite of open-water diving, sinkhole diving offers the eerie experience of dropping into the dark unknown. Hidden away in the jungles of Yucatán, Tamaulipas and Quintana Roo, Mexico's cenotes – from the Mayan word for 'sacred well' – plunge to dizzying depths. Divers have descended to 282m in the still, silent waters of Zacatón in Tamaulipas without ever reaching the bottom. Leave your fear of confined spaces at the surface – the average blue hole is a tangle of stalactites, stalagmites and winding limestone passages.
Tulum in Quintana Roo is the undisputed capital of cenote diving, but you'll need special certification for cave diving.