Down under a living legend

The Great Barrier Reef constitutes 1,000 miles of extraordinary lifeforms. Tony Wheeler picks its best dive sites

Mention scuba diving and thoughts of Australia's Great Barrier Reef consistently bubble to the surface. The GBR kicks off a bit south of the Tropic of Capricorn, just north of Fraser Island and about 100 miles off the Queensland coast. As it marches north it squeezes closer and closer to the coastline, fading to an end 1,000 miles from its starting point as it meets the huge outflow from the Fly River of Papua New Guinea. Coral reefs don't like freshwater.

Mention scuba diving and thoughts of Australia's Great Barrier Reef consistently bubble to the surface. The GBR kicks off a bit south of the Tropic of Capricorn, just north of Fraser Island and about 100 miles off the Queensland coast. As it marches north it squeezes closer and closer to the coastline, fading to an end 1,000 miles from its starting point as it meets the huge outflow from the Fly River of Papua New Guinea. Coral reefs don't like freshwater.

Although the outer barrier reef is a more-or-less continuous entity there are countless smaller "detached" reefs sheltered by the outer reef from the open Pacific Ocean. Of course divers and snorkellers encounter a vast range of marine life on the reefs. But the Great Barrier Reef is also home to pelagic (open water) species as well as visiting whales (moving north from their Antarctic home to breed in the reef waters), turtles (which lay their eggs on island beaches) and enormous populations of seabirds which nest on many of the islands.

For many visitors to Australia getting scuba diving certification is part of the fun and dive schools operate in many of the coastal towns and on the islands. Certification typically costs £120 to £250. When it comes actually to diving on the reef you've got three choices, you can stay on a Barrier Reef Island, you can make day trips to the reef from the coast or from one of the islands, or you can sail out to the reef and stay on a live-aboard dive boat.

If you're planning a scuba diving stay on a Barrier Reef island it's worth researching the island's diving credentials. Any island can claim to send you out on diving trips, but scuba diving is not a high priority at every island and some of them are a long boat trip away from the nearest dive sites. Lady Elliot and Heron islands, at the southern end of the reef, are definite exceptions. These are real coral cays with the reef just a paddle away. Heron is deservedly popular with a comfortable resort, excellent scuba diving and an on-going wildlife show which can make a visit a non-stop nature documentary with birds nesting, turtles laying eggs or baby turtles hatching. Nearby Wilson Island is a new, smaller, more secluded and exclusive resort. In contrast Lady Elliot is low-key, cheaper and completely dedicated to scuba diving: you can simply wade out to many dive sites from the shore.

Lady Musgrave Island is midway between the two southern resort islands and a popular daytrip from Bundaberg, the coastal jumping-off point for all these locations. It's one of the few coral cays along the reef with an enclosed lagoon big enough to sail into. You can also arrange to be dropped off and camp on the island. If there's a drawback to these Southern Reef islands it's in the name: they are right at the south of the Great Barrier Reef and in mid-winter (July and August) the water can be distinctly chillier than you'll find further north.

Continue north and Great Keppel Island has excellent dive sites within day-trip distance. The island has a host of accommodation possibilities aimed at younger visitors, ranging from a backpacker hostel to a Contiki resort. Head north again and you come to the Whitsundays, the biggest group of tourist islands along the Great Barrier Reef. Although they're close to the coast and some distance from the outer reef there are some good dive sites dotted around the very beautiful islands. Even better are the detached reefs 25 to 50 miles north of the Whitsundays. A stream of high-speed catamarans zip out there every day.

The Whitsundays have something for everybody from campers (you can be dropped off for a spot of Robinson Crusoeing) and backpackers, via families right up to international jetsetters at the upmarket Hayman Island Resort. There's even a Club Med on Lindeman Island. Alternatively Airlie Beach, the mainland jumping-off point for the Whitsundays, offers plenty more possibilities. If you want a taste of the reef on the cheap this is a good place to start, with numerous boats heading out for day-trip dives or longer explorations.

Continuing north, busy Townsville has Reef HQ, the best aquarium along the reef, and a variety of dive schools and dive operators making it one of the most popular dive centres. Orpheus, Hinchinbrook (with a sensational three-day coastal walk if you want a change from diving), Bedarra and Dunk are all popular islands between Townsville and Cairns, but none of them is a real diving centre. Cairns, on the other hand, has a telephone directory full of dive operators and constant shuttles of boats heading out to the reef.

A short flight north from Cairns is Lizard Island, a place for superlative scuba diving, luxurious accommodation and delicious food. There's excellent snorkelling right by the resort, terrific reef dive sites close to the island while the outer reef, including one of the best-known dive sites on the entire reef, is only a short boat trip away.

In 1770 Captain Cook climbed to Cook's Look, the highest point on the island, to spy a way out to the open sea after the Endeavour had struck the the reef and put in to Cooktown for protracted repairs. For many reef enthusiasts Lizard Island is the most spectacular island along the entire reef, but you don't have to be a big spender to stay there. Most of the island is a National Park and you can camp for just £1.50 a night.

Tony Wheeler is the founder of 'Lonely Planet'

DAY TRIPS AND LIVE ABOARDS

There are countless day trips running to Great Barrier Reef dive sites, usually featuring a couple of dives and lunch in between. Some on-the-spot research is necessary: there's a big difference between a small dive boat dedicated to scuba divers and a big catamaran taking sightseers, snorkellers and perhaps a handful of scuba divers as an afterthought. Day trip dive boats operate all along the reef, but particularly from Airlie Beach, Cairns and Port Douglas for around $100 (£42).

For the serious diving enthusiast there are live-aboards which enable you to explore the reef much more extensively. Live-aboard trips typically last from two to seven days and cost from $175 (£73) to $1,700 (£710). Two of the most popular dive sites along the entire reef are only accessible to live-aboard divers. The best shipwreck dive, the Yongola, is 15 miles offshore, midway between Airlie Beach and Townsville. Covered in a cloak of soft and hard corals and home to a veritable aquarium of sea creatures, the Yongola is a dive which rarely disappoints.

Further north the Cod Hole is the most popular dive for live-aboards operating out of Cairns, but is also conveniently close to Lizard Island for resort guests. The gigantic potato cod which congregate at the site can tip the scales at over 300 lbs but are accustomed dive groups and as a result are completely fearless and disarmingly friendly.

Two websites, www.diveoz.com.au and www.scubaaustralia.com.au, have comprehensive listings of dive operators and further information on everything from diving in the region, to equipment, costs, locations and medical considerations.