The Parker Point snorkel trail is the best known underwater trail at Rottnest and one of the few places in Western Australia where you can snorkel over live coral within a short bike ride of a ferry terminal. The point is protected by the Parker Point Sanctuary Zone, created to conserve its pocillopora (pink) coral; marinelife.org.au describes it as the southernmost known outcrop of pocillopora coral, influenced by the warm Leeuwin Current, with a great variety of temperate and tropical marine life and very clear water.

The trail consists of interpretive plaques fixed to the seabed - Samphire describes an 800 m trail with 12 plaques over a gentle sandy slope in 2-12 m - which explain the reef ecology as you swim. The Rottnest Island Authority's warm-water guide notes that the Salmon Bay and Parker Point area supports some 135 species of tropical fish, including wrasse, dusky morwong and schools of black bream, and corals such as cauliflower, brain, branching and plate forms. Seagrass and kelp beds alternate with the limestone and coral, giving a patchwork of habitats close to shore.

The site suits everyone from first-time snorkellers to scuba divers wanting an easy shore dive with long bottom times, and it is also reachable by boat. Because it is a sanctuary, fish are relatively tame and nothing may be taken. Take care with fins around the corals, avoid standing on the reef, and do not anchor on it. Combine it with Little Salmon Bay next door or with the Parker Point drop-off on a boat day.

From the Thomson Bay settlement cycle about 5 km south (around 17 minutes) or take the Island Explorer bus to Stop 5 (Parker Point). Bike racks and a short path lead down to the beach on the eastern side of the point. Enter from the sand and follow the trail markers out over the reef; the plaques are fixed to the seabed.

Boats can reach the area from Fremantle in about an hour, but anchoring on the coral is prohibited. Scuba divers must bring cylinders on the ferry.

SeaLink lists suitable winds as south-east through south, south-west, west and north-west - the point faces east and the trail is sheltered from westerly and south-westerly sea breezes. Strong easterly or north-easterly winds push chop onto the beach. Marinelife.org.au warns the exposed south-west side of the point gets rough, so stay on the eastern shore.

Summer water is warmest (up to about 24 C) thanks to the Leeuwin Current.

Enter from the beach on the eastern side, follow the trail plaques out over the reef at 2-6 m, reading each panel, then extend along the reef edge toward deeper water if on scuba before returning along the shoreline. 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.

Self-guided snorkel and shore dive; Rottnest Snorkel and other snorkel tours visit; snorkel gear hire in the settlement. No scuba operator required.