The Great Barrier Reef is the world’s largest coral reef system — visible from space, teeming with life and ranked among the planet’s great natural wonders. This guide rounds up the best of the reef for students, travellers and curious minds, from its enormous size and wildlife to the pressures it faces and how you can help. For more on the country’s remarkable wildlife, see our Australian animals hub.
The Reef at a Glance
- Location: off the coast of Queensland, from the northern tip of Queensland at Cape York down to Bundaberg
- Size: around 2,300 km long and 344,400 square kilometres
- Structure: roughly 2,900 individual reefs, around 900 islands and about 300 coral cays
- Depth: mostly shallow, with an average depth of 35 metres
- Status: UNESCO World Heritage since 1981 and the largest World Heritage Area on Earth
- Wildlife: one of the richest living systems on Earth
How Big Is the Great Barrier Reef?
To grasp the scale of the Great Barrier Reef, imagine a 2,300-kilometer stretch of living reef following the coast of Australia — longer than the Great Wall of China and roughly half the size of Texas. The Great Barrier Reef is the largest single structure built by living organisms, and the reef is the biggest coral expanse on the planet, bigger than the United Kingdom, Switzerland and the Netherlands combined.
This vast structure is made up of roughly 2,900 separate reefs and hundreds of islands, and it is the biggest coral reef on the planet by a wide margin. No other reef comes close to its scale, which is why people call the Great Barrier Reef the largest living thing on Earth.
20 Fun Facts and Figures
- The reef is visible from outer space.
- It is built by billions of tiny coral polyps, animals no bigger than a grain of rice.
- The reef is home to more than 1,500 species of fish.
- Around 400 species of hard coral grow here.
- The waters hold about 30 species of whales and dolphins.
- Six of the world’s seven marine turtle species live on the reef.
- Around 133 species of sharks and rays cruise the waters, including reef sharks.
- Humpback whales migrate north each winter to give birth in the warm waters.
- Dugongs, the so-called cows of the sea, graze the seagrass meadows.
- Minke whales visit the northern reefs each June and July.
- Giant clams in the region can live for more than a century.
- Green and loggerhead turtles nest on island beaches each summer.
- Heart Reef in the Whitsundays is a naturally heart-shaped coral formation.
- Bottlenose dolphins often ride the bow waves of reef boats.
- Clownfish, the stars of a famous animated film, shelter among anemones.
- Whitehaven Beach is regularly ranked among the world’s best beaches.
- Aboriginal and Torres Strait Islander peoples have looked after these sea Country connections for tens of thousands of years.
- The marine park was established in 1975 and UNESCO listing followed in 1981.
- Reef tourism generates billions of dollars every year.
- Corals can fluoresce in brilliant colours under ultraviolet light.
Marine Life of the Great Barrier Reef
An extraordinary variety of marine habitats exists here — sponge gardens thrive in sheltered inshore areas, while deeper offshore waters hide gardens of soft corals. From turtles and tropical fish to seabirds and dugongs, the marine life of the Great Barrier Reef reads like an encyclopedia. The Great Barrier Reef is one of the most complex ecosystems in the world, and scientists estimate it supports thousands of species beyond the fish, corals and birds already catalogued.
A Reef Ecosystem Like No Other
Why does this living structure matter so much? Beyond its beauty, the Great Barrier Reef acts as a giant nursery. Juvenile fish shelter among the coral, seabirds nest on the islands, and turtles return to the very beaches where they hatched. The reef also shields the coastline itself, absorbing wave energy from storms and cyclones.
Snorkel and Dive the Great Barrier Reef
For visitors, the reef offers an incredible Great Barrier Reef experience. You can snorkel over shallow coral gardens straight off the beach at islands like Green Island, join a dive trip from Cairns in North Queensland, or sleep on a live-aboard boat among the outer reefs. Many travellers plan their trip around our Australian seasons guide to catch the best visibility and warmest water.
Protecting the Great Barrier Reef
The reef is under pressure. In recent decades the Great Barrier Reef has experienced several mass coral bleaching events, including in 2016, 2017, 2020 and 2022, driven by rising sea temperatures. The northern Great Barrier Reef was hit hardest during the 2016 event, and the health of the reef depends on limiting further warming. Outbreaks of the crown-of-thorns starfish and coastal run-off add to the stress.
The protection of the Great Barrier Reef is coordinated by the Great Barrier Reef Marine Park Authority, while the Great Barrier Reef Foundation funds restoration science. Every visitor can act to protect the reef by choosing eco-certified operators, using reef-safe sunscreen and reporting sightings through citizen science apps. Around two million visitors take reef trips every year, and the reef tourism industry — attracting millions of visitors each year — depends on keeping the reef healthy for generations to come.
Where in Queensland Is the Great Barrier Reef?
The reef runs along the north-eastern shores of Queensland, from Cape York in the north down to the southern end of the marine park. Gateway towns include Cairns, Port Douglas, Airlie Beach and Townsville.
How Old Is the Great Barrier Reef?
The reef’s origins date back around half a million years, but the living structure you can visit today is roughly 6,000 to 8,000 years old, growing on older limestone platforms left by previous generations of coral.
Is the Great Barrier Reef One of the World’s Seven Wonders?
Yes. It is widely listed among the seven natural wonders of the world, alongside places like the Grand Canyon and Mount Everest, and it holds World Heritage status.
Why Is the Reef on the UNESCO List?
The reef was inscribed by UNESCO in 1981 in recognition of its outstanding natural significance — its scale, its beauty, its stage of biological evolution and the sheer diversity of life it supports. It was one of the first places anywhere to earn all four natural criteria.
What Is the Biggest Killer of the Great Barrier Reef?
Climate change. Rising sea temperatures trigger repeated bleaching of the corals, and scientists agree that cutting global emissions is the single most important action for the reef’s long-term survival.
How Many Species Live on the Great Barrier Reef?
Beyond the 1,500-plus fish species and 400 hard corals, the reef supports 133 species of sharks and rays, over 215 species of birds, and one of the largest populations of dugongs on the planet.
Can You See the Great Barrier Reef From Space?
Yes — astronauts have photographed the reef from orbit, making it one of the few living structures visible from space.
Can You Get to the Great Barrier Reef From Airlie Beach?
Yes. Airlie Beach is the main gateway to the Whitsundays, with day trips sailing out to fringing reefs in under two hours, plus longer overnight charters.
How Can You Help Protect the Great Barrier Reef?
Choose eco-certified tour operators, use reef-safe sunscreen, obey zoning rules when boating, reduce your carbon footprint at home, and support organisations funding reef restoration. Small choices add up when millions of people make them.
References and Sources
- Official reef management facts: gbrmpa.gov.au
- Barrier Reef Foundation research: barrierreef.org