Twelve Apostles Marine National Park – Thunder Cave & outer reefs

Meet the site

The Twelve Apostles Marine National Park protects 7,500 hectares of Southern Ocean along the most dramatic 17 km of the Great Ocean Road, from Port Campbell east past the Apostles toward Princetown. It is the second largest marine national park in Victoria and, according to Parks Victoria, holds the state's greatest diversity of invertebrates on its limestone reefs. Underwater the coast continues what the cliffs show above: soft limestone cut by the sea into arches, canyons, overhangs and caves, interspersed with sand plains, with giant kelp forming mini-forests that reach the surface from 10 m in places and extensive beds of common and bull kelp elsewhere. Sponge gardens and colourful invertebrate communities cover the shaded faces, and the fish life includes magpie perch, blue-throat wrasse, Port Jackson sharks, southern rock lobster in large numbers and weedy seadragons on the sand edges. The Loch Ard wreck under Mutton Bird Island lies within the park and is recorded separately.

The named dive that locals talk about is Thunder Cave, a sea cave in the cliffs a short run east of Port Campbell whose underwater entrance is about 25 m deep and, in the words of one regional guide, full of crayfish. Nearby The Blowhole and the collapsed arches and stacks between it and Loch Ard Gorge give wall and cavern diving in 10–25 m, and further east the reefs off the Twelve Apostles themselves are kelp-covered limestone ridges and canyons in 15–30 m that almost nobody has dived because getting there requires a rare calm day and a long run from a crane-launched boat. All of this is expedition-grade diving on a coast where the sea is pounding the cliffs most days of the year. Parks Victoria's guidance is that diving here should only be undertaken by experienced divers with extensive local knowledge, and that is the right frame: this is not a site to plan a holiday around, but for a well-organised group with local boat support on an autumn high, it is some of the wildest and least-seen reef diving in Australia, in a no-take park where the crayfish have never been touched.

What you might see

Southern rock lobster (abundant), weedy seadragons, magpie perch, blue-throat wrasse, Port Jackson sharks, sea sweep, giant kelp, bull kelp, sponge gardens, colonial ascidians, bryozoans, Australian fur seals, short-tailed shearwaters, occasional southern right whales in winter

Location

Limestone reefs, arches, canyons and sea caves along the 17 km of coast between Port Campbell and the Twelve Apostles, inside the 7,500 ha marine national park; Thunder Cave lies just east of Port Campbell.

Facilities nearby

Port Campbell jetty crane (permit), Port Campbell township with toilets, cafes, fuel and visitor centre; no air fills nearer than Warrnambool.