Duck Rock sits off Bathurst Point on Rottnest's north-east corner, within walking distance of the ferry, and is one of the few genuine scuba shore dives on the island. It is also the site of Rottnest's earliest recorded shipwreck: the 124-ton, two-masted wooden schooner Transit, wrecked on 18 May 1842 when she struck the rock while rounding the island after the master had gone below leaving directions with the helmsman. Nothing of the vessel survives - the WA Museum describes it as broken up with little remaining - but an underwater plinth marks the site beside an interesting cave in the reef.

The dive itself is a limestone reef dive. After a fairly long swim over the shallows you reach the rock, outside which the reef drops off into medium-sized caves and overhangs. The walls are dressed with sponges and colourful invertebrates, and the usual north-coast reef fish - sweep, bullseyes, wrasse, buffalo bream and old wives - shelter in the caves. Maximum depth is only about 6 m, so bottom times are long.

Because it needs no boat, Duck Rock suits self-sufficient divers on a Rottnest holiday who are prepared to carry gear from the settlement, as well as snorkellers in calm weather. It is also a useful complement to the Transit Reef wrecks, which are nearby but need a boat or a much longer swim. Keep in mind the heavy boat traffic along this shore on summer weekends. It is worth combining with a visit to the WA Museum land trail, which begins at the island museum and overlooks the area where the Transit, Gem, Janet, Macedon and Denton Holme were lost.

Take the Rottnest Express or SeaLink ferry from Fremantle (about 25-30 minutes) or Perth to the main jetty at Thomson Bay. Walk or cycle north from the settlement along the shoreline towards Bathurst Lighthouse (about 500 m to 1 km); scuba gear has to be carried the whole way, so a trolley or bike trailer helps. Enter from the sand near Bathurst Point and surface-swim out over the shallow reef to Duck Rock, towing a float and flag.

Private boats can anchor on sand clear of the reef. There is no dive shop or air on the island.

Sheltered from the south-west and from the afternoon sea breeze, but exposed to north and north-west winds and winter frontal swell, which make the entry rough and stir the sand. Dive in light easterly or south-easterly conditions, ideally in the morning. Boat traffic to and from Thomson Bay passes close by.

Surface-swim to Duck Rock, descend on its outer (northern) side and follow the reef drop-off at 4-6 m, checking the medium-sized caves and overhangs; find the museum plinth near the cave, then return along the edge to the shallows and exit at the entry beach.

No regular operator; a self-guided shore dive for divers bringing their own cylinders on the ferry, and an occasional club or private-boat stop.