Longreach Bay is a broad bay on Rottnest's north coast, a short ride west of the settlement. SeaLink describes it as offering calm conditions and attractive underwater scenery, with vibrant corals, tropical fish and occasional dolphins, suitable for all experience levels. It is also a popular boating anchorage in summer.

The reef along the edges of the bay and around the limestone points holds the usual north-coast community: wrasse, juvenile bream and other small reef fish over patches of coral and weed, with seagrass and sand in the centre of the bay where rays feed. Being close to the settlement, it is easy to reach for a quick snorkel.

It suits families and beginners in calm, southerly weather. It is too shallow for a meaningful scuba dive, but it is a convenient alternative to The Basin and a good first stop on a north-coast cycle.

Published detail is limited to snorkel guides, so depths and features here are indicative. Boat traffic is the main concern in summer; stay near the shore and use a float and flag if venturing toward the moorings.

Fay's Bay and Geordie Bay are just to the west for more of the same with deeper limestone caves.

Rottnest's north-coast bays are the island's summer snorkelling grounds because they sit in the lee of the prevailing south-westerly sea breeze. The Rottnest Island Reserve bans spearguns and handspears across all island waters, so fish throughout the bays are relatively approachable, and the Island Explorer bus and flat cycling road link them all. The general rule is simple: in a southerly, snorkel the north side.

About 1.5-2 km from Thomson Bay along the north-coast road; cycle or walk and leave bikes above the beach. Enter from the sand; boats moor offshore in summer. Snorkel gear can be hired in the settlement; scuba divers must bring filled cylinders from Perth on the ferry, as there are no fills on the island.

Ferries (Rottnest Express and SeaLink) run from Fremantle, Perth and Hillarys to Thomson Bay; bikes can be hired on the island or brought on the ferry, and the Island Explorer bus circles the island with stops near most bays.

SeaLink lists east, south-east, south, south-west and west winds as suitable. North and north-westerly winds make it rough. General pattern at Rottnest: summer brings calm morning easterlies followed by a strong south-westerly sea breeze from late morning, so dive early; winter brings north-westerly fronts and large swell, with clear, calm spells between them.

Check the Bureau of Meteorology coastal forecast for swell height and period before committing.

Snorkel from the beach along the reef edges at either end of the bay, returning along the shore. Snorkellers should stay within easy reach of the exit point and swim with a buddy; scuba divers at these depths need no safety stop but should ascend slowly and surface near the float.

No operator needed - self-guided snorkel/shore dive. Snorkel gear hire from Pedal & Flipper and other outlets in the Thomson Bay settlement; guided snorkel tours (Rottnest Snorkel) run from Thomson Bay. Scuba divers bring cylinders from Perth - no fills on the island.