Great Barrier Reef Guide

Discover the world’s largest living structure and one of the seven natural wonders of the world.

Stretching more than 2000km (1243mi) in length and covering an area of more than 23 million hectares, the World Heritage-listed Great Barrier Reef comprises more than 2100 individual reefs plus 500 islands with fringing reefs.

Explore a magical underwater world that is home to more than 400 varieties of coral and 1500 species of tropical fish and marine creatures – the perfect location for scuba diving and snorkelling.

Look out for clownfish, red bass, red-throat emperor, several species of snapper and coral trout as well as large numbers of green and loggerhead turtles, dugongs, sharks, giant manta rays and sea snakes.

During winter, from June to August, humpback whales gather to breed in the warm waters south of the Reef around Hervey Bay, and as far north as Cairns.

What to expect…

The Great Barrier Reef comprises three main reef types: fringing reef – surrounding offshore islands and along the mainland; ribbon reef – long, thin reefs that lie along the outer edge of the continental shelf and are only found north of Cairns; and platform or patch reefs – the most common kind of reef that can stretch up to 16km² (6mi²) off the continental shelf.

The rich colours of the coral reef are best appreciated with lots of light – so the nearer the surface, the brighter and richer the marine life – just perfect for snorkelling.

Most reef cruises offer a guided snorkel tour or snorkel safari as part of the cruise, and these are often led by guides trained by marine biologists.

Day-trip fares typically include snorkel gear such as fins, mask and snorkel, (and wet suits in winter should you need them).

A day trip to the Reef also offers the opportunity to go scuba diving – even if you have never dived before.

Most major cruise boats and many dedicated dive boats offer introductory dives (known as resort dives) that allow you to dive without certification to a depth of 6m with an instructor.

You need to complete a medical questionnaire and undergo a 30-minute briefing on the boat before diving.

Alternatively, if you would prefer not to get wet, stay dry and enjoy the reef views from an underwater viewing chamber, glass bottom boat or semi-submersible.

Getting to the reef…

The Great Barrier Reef is easily accessible on a day trip via fast, ultramodern catamarans, boats, seaplanes and helicopters.

Many of the larger boats tie up at their own private permanent pontoons anchored to a platform reef. The pontoons have glass-bottom boats, dry underwater viewing chambers, sun decks, shaded seats and often showers.

While Cairns is considered the gateway to the Great Barrier Reef, boats also leave from Airlie Beach, Cooktown, Port Douglas, Mission Beach, Townsville, Yeppoon, Mackay, Gladstone and 1770.

Typically, the further north you leave from, the shorter the trip to the reef. There are no shortages of great dive sites all along the reef from wherever you happen to be on the Queensland coast.

A choice of dive operators offer PADI-style diving trips and guided snorkelling tours to various locations on the Great Barrier Reef from Cairns and Port Douglas as well as from Airlie Beach and Hamilton Island in the Whitsundays.

Quicksilver Connections ( runs fast, modern catamarans from both Port Douglas and Cairns marinas to large commercial activity diving platforms.

A day trip to Agincourt Reef on the Outer Great Barrier Reef costs around A$200, with options including marine-biologist-guided snorkelling tours (A$47-$67), scuba diving (A$99-A$149), 10-minute scenic heli-tours (A$148) and ‘Ocean Walker’ sea-bed tours (A$146).

Poseidon ( offers guided snorkelling and diving day trips to three separate sites on the Agincourt Ribbon Reef on smaller, less crowded boats, with longer cruises to Outer Great Barrier Reef sites. You can expect excellent pre-dive briefings by a marine naturalist.

In addition, expect to pay an A$5.50 reef tax that goes to the Great Great Barrier Reef Marine Park Authority, who are responsible for making tourism to the Reef ecologically sustainable.

From Cairns

About 20 reefs lie within a two-hour boat ride from Cairns. Some reefs are quite small while others are kilometres wide.

Three of most popular reefs for snorkelling and diving on a day trip are Norman, Hastings and Saxon reefs, which are also just a short boat ride from one another.

Cairns also has several coral cays and reef-fringed islands within the Great Barrier Reef Marine Park, which are less than an hour from the city marina.

The 15-hectare coral cay of Green Island offers great snorkelling and diving equal to that of most other places on the Great Barrier Reef.

Fitzroy Island is just 45 minutes by boat from Cairns and provides a coral beach with great snorkelling close to the shore as well as walking trails through the rainforest-covered national park that covers the island.

The uninhabited Frankland Islands also offer pristine white-sand beaches, colourful coral and reef fish just 45km (28mi) south of Cairns; visit in February and March to see dozens of baby green sea turtles hatching in the sand.

Or you could snorkel the colourful reefs surrounding Michaelmas Cay, just 30km (18mi) off Cairns and reknown for its 27,000 seabirds. Upolu Cay is 25km (15mi) from Cairns and is home to numerous dugongs as well as great snorkelling.

Those preferring a two- or three-day live-aboard diving experience should head out to the ribbon reefs that lie on the outer reef edge: Steve’s Bommie, Dynamite Pass and Cod Hole are three of the most popular dive sites from Cairns.

From Port Douglas

The reefs and marine life off Port Douglas compare favourably with those found around Cairns. You can easily find colourful and varied reefs close to shore. Some of the most popular reefs to snorkel and dive include the Low Isles, Agincourt Reef, Turtle Bay, Opal Reef, Tongue Reef and St. Crispin Reef.

At 15km (9mi) offshore, the Low Isles are the closest reef site from Port Douglas. While the coral is not quite as dazzling as the Outer Reef, the reef here is just a short wade from the beach – perfect for timid snorkelers – and is home to numerous colourful reef fish as well as turtles.

The two coral cays also offer the opportunity of lazing under palm-thatched beach umbrellas and sunbathing on the beach, and are covered with rich vegetation – the larger cay is home to thousands of nesting Torresian Imperial pigeons.

At Agincourt Ribbon Reefs, you can choose from 22 excellent dive sites, including Nursery Bommie, a 24m pinnacle that is home to schools of barracuda, rays, sharks and moray eels; Three Sisters, a popular haunt of grey reef sharks, wrasse, parrot fish, anemones and resident Clown fish; and Castle Rock, a haunt of white-tipped reef sharks, giant clams, trigger fish and staghorn coral gardens.

Turtle Bommie is popular with resident green turtles, clown fish and schools of sweetlip while Barracuda Bommie is home to coral gardens, giant clams and schooling barracuda. The Cathedrals is a collection of coral pinnacles and swim-throughs.

More about Port Douglas

From the Whitsundays

The Whitsundays offers great snorkelling around the islands as well as excellent diving in the outer Reef, with visibility around 15m to 23m. The reef here has a dazzling range of corals, a rich array of marine life, including whales, mantas, shark, reef fish, morays, turtles and pelagics, as well as many drop-offs and drift dives.

One of the most popular sites on the Outer Reef is the Stepping Stones on Bait Reef. Here, a series of pinnacles offer caverns, swim-throughs and channels that abound with marine life.

To see groupers, head to Groupers Grotto on Net Reef, and to see dolphins check out Net Reef.

The Whitsundays’ Hayman Island offers a popular snorkel and dive site at Blue Pearl Bay, where you can walk right in off the beach to see gorgonian fans, coral gardens and numerous species of reef fish, including Maori wrasse and manta rays. Mantaray Bay on Hook Island is also renowned for its range of marine life.

More about the Whitsundays… and Arlie Beach

From Townsville

For some of the best diving on the Great Barrier Reef, head out to Flinders Reef. Although located in the Coral Sea, around 240km offshore, it offers 30m visibility, big walls, pinnacles and excellent coral with abundant fish life, including mantas, rays, turtles and sharks.

Closer to shore is one of Australia's best wreck dives, the SS Yongala – sunk during a cyclone in 1911. Still largely intact, the sunken remains lie 16km (10mi) off the coast, (around 90km (56mi) from Townsville), in 15m to 30m of water, with visibility from 9m to 18m.

Surrounded by coral, the wreck is the haunt of barracuda, grouper, rays, sea snakes, turtles, moray eels, shark, cod and a variety of colourful reef fish.

Note: the Yongala is not for beginners and most dive companies require divers to have advanced PADI or to have logged a minimum of 15 dives with open-water certification.

More about Cairns…

Latest update: Great Barrier Reef: 12 May, 2022