Pearson Island, one of the Investigator Group off the west coast of Eyre Peninsula, is among the most remote dive sites in South Australia. The Marine Life Society describes a 213-hectare island split into northern and southern land masses by a shallow tidal channel, with an automatic light at its centre and a safe anchorage and landing point in a cove on the eastern side. It is noted for clear water.

Underwater, large granite blocks go out to depths of more than 30 m. The boulders shelter gorgonia, soft corals, zebrafish, wrasse, moonlighters, nannygai, wobbegongs and harlequin fish, and seals are regularly seen. About 50 Australian fur seals breed on a sheltered beach and should not be disturbed.

The island is also famous among biologists for its isolated populations of rock-wallabies and other wildlife that have evolved in isolation. Pearson Island is an expedition destination: far offshore, exposed to the Bight, and accessible only with a large, well-equipped boat and a multi-day weather window. It is protected as a conservation park, and landing requires authorisation.

For the few who reach it, the combination of clear oceanic water, towering granite and unfished marine life is exceptional. It suits highly experienced divers with expedition-level planning and safety equipment. Any trip should include oxygen, a satellite communication device and a conservative dive plan, since evacuation would require an aeromedical retrieval from the mainland.

Pearson Island lies roughly 65 km west-south-west of Elliston in the Investigator Group. It is reached only by a large, seaworthy boat from Elliston (2-3 hours each way) or as part of a multi-day expedition; a safe anchorage and landing point exists in a cove on the eastern side. The island is a conservation park and landing requires authorisation.

The west coast of Eyre Peninsula faces the Great Australian Bight and receives almost constant south-westerly Southern Ocean swell; open-coast sites need swell under about 1.5 m and are only diveable a handful of days a month, usually after several days of northerly or easterly winds, which blow offshore. The large sheltered bays (Coffin Bay, Waterloo Bay, Venus Bay, Baird Bay, Streaky Bay, Denial Bay) are protected from swell and can be dived in most conditions except strong onshore winds. Summer brings strong afternoon south-easterly sea breezes; winter brings cold fronts with big swell but also calm, clear spells.

Water is cool: about 14-15°C in winter and 17-21°C in summer. Pearson Island is far offshore in the Bight and needs a multi-day window of calm weather.

From the east-side anchorage, descend along the granite blocks to 15-25 m, weaving among boulders for gorgonia, wobbegongs and harlequin fish, then ascend along the rock with seals.

Depths beyond 30 m available – conservative planning essential given many hours to any chamber.

No operator; scientific expeditions and rare private expeditions only.