What’s the difference between inner and outer reef?

Understand the difference between the inner and outer Great Barrier Reef and which one you should visit on your day tour.

The Great Barrier Reef is a remarkable natural treasure off the north-east coast of Queensland. The entire reef system covers an area of 2300 kilometres and includes close to 3000 individual reefs and 900 islands. Home to thousands of species of fish, corals and other marine animals, the Great Barrier Reef offers travellers unparalleled snorkelling and diving opportunities.

If you are planning a trip to the Great Barrier Reef, you may be confused by the references to the inner and outer reef when researching tours to the area. So what is the difference between them and which should you chose?

  • Outer Reef

    Most images you have seen of the vibrant corals and colourful fish are of the outer reef, and this is what most people expect to see when they head to the Great Barrier Reef. What people don’t realise when they view these images is that most outer reef sites are far offshore and take 1.5 – 2 hours by high speed catamaran to reach. Some of the outer reefs that tours from Cairns visit include Hastings Reef, Saxon Reef and Breaking Patches.

    The distance from the mainland is not necessarily a bad thing. For starters, the visibility at the outer reef if much better than the inner reef, up to 45 metres compared to an average of 5 metres, because of the absence of run-off from nearby islands. Second, the outer reef grows from the ocean floor rather than from the islands, forming coral bombies and dramatic drop-offs that make for impressive snorkelling and diving. Outer reef sites are home to more hard coral species and larger fish species than the inner reef.

  • Inner Reef

    The inner or fringing reef are parts of the reef closer to the mainland or islands. Inner reef sites are generally made of more soft corals which smaller fish species call home. Seagrass meadows, important feeding grounds for turtles and dugongs, are often found around island in the inner reef. The inner reef’s proximity to land makes it accessible from the beach, and the sheltered waters mean it’s perfect for beginner snorkellers.

    The Whitsundays is the location best associated with the inner reef, but you can visit two spectacular inner reef locations from Cairns. Green and Fitzroy Islands can be easily reached by a short boat trip from the Marlin Marina. The islands also have a variety of alternative activities available so you can enjoy your snorkel and return to laze about on the beach or explore the island.

Which is better?

Both the inner reef and outer reef offer snorkellers an amazing chance to explore the underwater world of the Great Barrier Reef. Each has its advantages, unique environment to explore and different species to admire. Honestly, if you’re in Cairns we would recommend visiting both! But if you are trying to chose between the two, then we would suggest a boat out to the outer reef. The impressive coral formations and array of marine life cannot be matched!

Related article: Which is the best reef in Great Barrier Reef?

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