Cape Wiles Lagoon is one of the more remarkable sites on the wild lower Eyre Peninsula coast. The Marine Life Society describes a sheltered lagoon about 30 km south-west of Port Lincoln, reached by boats launched off the beach at Fishery Bay by 4WD, with an island hosting a New Zealand fur seal colony, and water that is always clear and calm inside. The lagoon's bottom features car-sized boulders at 6-15 m, and a small cave about 50 m long at 15 m (a torch is needed).

The Society lists western blue groper, gorgonians, crayfish, ascidians and sponges, and in the lagoon morwong, blue groper, harlequin fish, drummer, cuttlefish, blue devils and perch. Fur seals from the island regularly investigate divers. Access is the challenge.

Whalers Way, the scenic coastal drive to the area, crosses private property and requires a permit and key, and a beach launch is only possible on the rare calm days this coast offers. The surrounding coast is spectacular but exposed, with cliffs and crevasses such as Theakstones Crevasse, which the Society notes is rarely dived due to its exposed position. Cape Wiles suits adventurous, self-sufficient divers with a 4WD and small boat, and rewards them with clear water, seals and one of the best-kept secrets of Eyre Peninsula diving.

Tell someone your plans, carry a satellite beacon or VHF radio, and be prepared to abandon the trip if the swell rises while you are out – the beach relaunch at Fishery Bay can be dangerous in any surf.

Port Lincoln is about 650 km (7 hours) by road from Adelaide via Port Augusta and the Lincoln Highway, or a 45-50 minute flight (Rex/QantasLink). Drive about 30 km south-west of Port Lincoln to Fishery Bay (near the start of Whalers Way, which crosses private property and needs a permit and key from local service stations/visitor centre). Small boats are launched off the beach at Fishery Bay by 4WD and run to Cape Wiles lagoon.

Only attempt in settled weather.

The lower Eyre Peninsula coast around Whalers Way and Cape Wiles faces the full Southern Ocean and is usually pounded by south-westerly swell; the beach launch at Fishery Bay and the run to the lagoon are only feasible on rare calm days with low swell and light winds. Once inside, the Marine Life Society describes the lagoon water as always clear and calm. Winter fronts make the area inaccessible for long periods.

Anchor in the lagoon, dive among the car-sized boulders at 10-15 m, visit the 50 m cave at 15 m with a torch, and finish near the seal island.

No operator; locals with 4WD and small boats.