Francois Peron National Park covers the northern Peron Peninsula, a landscape of red sand cliffs, white beaches and birridas (salt pans) between the two arms of Shark Bay. The Shark Bay tourism guide lists two snorkel sites here: Gregories, a shallow coral wall 2-3 m deep just offshore with small coral patches and fish, and Bottle Bay, a reef 80 m offshore in 2-4 m with corals, sponges, tropical fish and crustaceans.

Both require a genuine 4WD trip on soft sand tracks and self-sufficiency, and they are best on calm mornings. The surrounding waters are home to dugongs, turtles, rays and sharks.

Francois Peron National Park is north of Denham (entrance about 4 km from Denham on the Monkey Mia Road). Beyond Peron Homestead the tracks are soft sand and require high-clearance 4WD with lowered tyre pressures. Gregories and Bottle Bay are on the western side of the peninsula near Cape Peron (about 50 km from Denham, 1.5-2 hours).

Park fees apply.

Shark Bay is dominated by strong southerly winds, which blow most days from about October to March and often exceed 20 knots by late morning; the calmest conditions are in April-June and on early mornings. The inner bay is shallow and well protected from ocean swell, but the western shores of Dirk Hartog Island and Steep Point face the full Indian Ocean. Water is 17-19°C in winter and 23-26°C in summer.

These sites face the western arm of Shark Bay and are exposed to southerly and south-westerly winds; snorkel in the morning.

At Gregories, snorkel along the shallow coral wall just offshore. At Bottle Bay, swim 80 m out to the reef and circle it before returning.

No operator – independent snorkelling.