The Pericles is one of Western Australia's most famous shipwrecks. Built by Harland & Wolff in Belfast for George Thompson & Co.'s Aberdeen Line and launched on 21 December 1907 at a cost of £240,000, she was a 10,925-ton, 152.6 m passenger liner on the London-Cape Town-Australia route. On 31 March 1910, steaming at 14 knots in good visibility, she struck an uncharted rock near St Alouarn Island, about 3.5 nautical miles south-east of Cape Leeuwin. Water flooded the forward hold within minutes; lifeboats were launched, and all 413 people aboard survived - the only casualty was the ship's cat. She sank a few kilometres south of the lighthouse with a cargo that included butter, mutton, wool, hides, apples, tallow, coconut oil and lead.

The wreck lies in about 35 m and is spread over an area roughly 180 by 70 m. Marinelife.org.au describes a large jumble dominated by three boilers and the upright port engine; Wikipedia lists twin engines, propeller shafts, boilers, anchors and parts of the frame, with lead ingots remaining in the stern. WreckSploration notes the engines stand about 10 m high and that strong currents and limited visibility prevented a full survey in 2024.

It is rarely dived, by a few hardy locals and enthusiasts, and is protected under the Underwater Cultural Heritage Act 2018. It suits experienced deep divers with good current skills diving from a well-crewed boat. A replica of the Pericles features in the Busselton Jetty underwater sculpture park, and the Cape Leeuwin Lighthouse precinct tells the story of the sinking.

Accessed by boat from Augusta - launch at the Augusta boat harbour/ramps and run south past Cape Leeuwin to the St Alouarn Islands area (about 6-7 km from the cape). Drop a shot on the GPS mark. Swan Dive occasionally runs trips and advertises them through its newsletter and social media.

Boat ramps along Geographe Bay include Bunbury (Casuarina), Busselton, Port Geographe, Quindalup and Dunsborough; on the Capes coast the Canal Rocks, Gracetown and Hamelin Bay ramps are small and swell-exposed. Check the forecast, carry a marine radio and log a trip plan with the local Marine Rescue group.

Where the Indian and Southern oceans meet, the site is noted for big currents and swell (marinelife.org.au); WreckSploration reports strong currents and limited visibility. Dive only on rare calm days with small swell and light winds, ideally at slack water; summer and autumn give the best chances. General pattern on the Capes and Leeuwin coast: summer mornings often have light easterly (offshore) winds before a south-westerly sea breeze, and long-period south-westerly groundswell can arrive on otherwise calm days; winter fronts bring big swell and north-westerly winds.

Check the Bureau of Meteorology swell forecast, not just the wind.

Descend the shot to the wreckage at about 30-35 m, head for the three boilers and the upright port engine, then ascend the shot or on a DSMB with a planned safety or deco stop, allowing for strong current. Agree a turn pressure before descending (half gas, or a third where current is likely), carry a DSMB, and make a 3-minute safety stop at 5 m.

Nitrox or air within no-deco limits for most; technical divers use deco gases for longer bottom times; live-boat pickup and DSMBs essential.

Swan Dive (Busselton) runs occasional special trips; otherwise private boats and technical/wreck groups (WreckSploration surveyed it in 2024). Nearest dive services: Swan Dive (Busselton/Port Geographe) for fills, hire, nitrox and charters; no dive shop in Margaret River or Augusta.