For more than 80 years the waters off the west end of Rottnest were Western Australia's official dumping ground for unwanted ships. Wikipedia and the WA Museum describe an area about 11 km across where at least 47 historically significant vessels are known to have been sunk since 1910 - old sailing-ship hulks used as coal barges, obsolete steamers, tugs, whale chasers, naval vessels and more. The seabed across the area ranges from about 50 m to 200 m, placing most of the wrecks beyond recreational reach.

Only a handful have been dived. WreckSploration has surveyed and 3D-modelled several, including the Thornliebank (46 m), the 'Clipper' (believed to be the Maranda, 65 m), the whale chaser Kos VII (82 m), the minesweeper HMAS Junee (83 m), the SS Cape Otway (85 m) and the iron ship Sesa (90 m); it also located the Dutch submarine K XI in 2025 in about 40 m on the edge of the area (listed separately in the Perth region). The UWA Underwater Club reports diving a 58 m 'shallow wreck' and the 65 m Clipper. HMAS Derwent, sister ship of HMAS Swan, was sunk in the graveyard on 21 December 1994 about 12 nm west of Rottnest after weapons-effects trials that left her too damaged to prepare as a dive wreck; she lies in deep water and is not a dive site.

This is exploratory technical diving: trimix, long decompression, open water, no moorings and complete self-reliance. The reward is intact hulls that very few people have ever seen.

The graveyard lies well offshore to the south-west and west of Rottnest, roughly 30-40 km from Fremantle. There are no moorings or public marks; teams run from Fremantle or Woodman Point in capable private or club boats (UWA Underwater Club, WreckSploration) with accurate GPS positions and sounders, drop a shot line onto the wreck and dive with surface support. Allow 1-1.5 hours each way.

This is not a commercial charter destination.

Open ocean with no shelter: dive only in low swell and light winds, typically calm summer and autumn mornings before the south-westerly sea breeze. Currents can be strong at depth and on decompression; drifting deco under a DSMB with a chase boat is normal. Blue water visibility is usually good.

Shot the target wreck, descend on the line to the deck, conduct a planned survey or tour for a limited bottom time, then ascend the shot or drift under a DSMB for staged decompression on planned gases. 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.

Trimix and staged decompression required for most wrecks (Thornliebank at 46 m is borderline air/nitrox-deep territory; 65-90 m wrecks require normoxic or hypoxic trimix). Rebreathers commonly used. Drift deco under DSMB with dedicated chase boat.

Obtain positions from WA Museum/WreckSploration; do not disturb protected hulks.

No commercial operator. Explored by technical diving teams - UWA Underwater Club (the only Perth club diving the area, per its site list) and the WreckSploration / Maritime Discovery Group team, which has surveyed and modelled several wrecks.