Three-hour snorkel tours cross from Fremantle to the sheltered bays of Rottnest Island, where qualified guides lead about forty-five minutes in the water over limestone reef and seagrass. This is a guided outing rather than a gear-drop, with instructors reading the conditions and marine life of the island's protected coves, and departures also available from Thomson Bay. Trips run daily through the season, opening a slice of Western Australia's clear near-shore water a short hop from Perth.