Turtle Bay, at the north-east corner of East Wallabi Island, is the most visited snorkelling spot in the Abrolhos because it is the destination for fly-in day tours from Geraldton that land on the island's airstrip. Marine Life Network calls it brilliant, with conditions ranging from a shallow swim to pristine coral reef: blue staghorn corals, plate and finger corals, buffalo bream, sergeant majors and other reef fish in 2-5 m.

The bay is sheltered from the afternoon southerly, the water is clear and warm thanks to the Leeuwin Current, and the reef starts close to the beach, making it ideal for snorkellers of all ages. East Wallabi Island also has walking trails, tammar wallabies and nesting seabirds, and neighbouring West Wallabi holds the Wiebbe Hayes forts from the Batavia story.

For divers on liveaboard trips, Turtle Bay makes a relaxed shallow dive or a night snorkel. Anchoring must be in sand, clear of the coral.

Fly-in day tours usually allow an hour or two in the water, so arrive with a well-fitting mask and a rash vest or thin wetsuit for sun protection. Liveaboard divers get the bay to themselves in the early morning or evening, when turtles and rays are most often seen over the seagrass fringe. Take all rubbish off the island. Reef shoes help on the beach rubble.

The Houtman Abrolhos lie 60-80 km west of Geraldton (about 420 km north of Perth). There is no public accommodation or camping on the islands, so divers visit on liveaboard trips departing Geraldton (a 3-5 hour crossing), on private vessels using the public moorings, or – for snorkelling only – on scenic-flight day tours that land on East Wallabi Island. East Wallabi Island has an airstrip used by Geraldton scenic flight operators for day tours that include a walk to Turtle Bay and a snorkel on the reef.

Liveaboards and private boats anchor in the bay. The beach is at the island's north-east corner.

The Abrolhos sit on the edge of the continental shelf in the path of the warm Leeuwin Current, which keeps water at 20-24°C and supports the world's southernmost major coral reefs. The islands are exposed to the south-west swell and to strong southerly winds that blow most afternoons from October to March; the crossing from Geraldton is often rough. Marine Life Network recommends March-May and September-November; late summer-autumn highs give the calmest seas.

Western rock lobster season (15 March-30 June) brings fishing camps and boat traffic. Turtle Bay faces north-east and is sheltered from the prevailing southerly winds and south-westerly swell, which is why it is the day-tour snorkel stop.

Enter from the beach, snorkel out over the seagrass to the coral reef edge and follow it along the bay, returning to the beach.

Liveaboard only for diving: Image Dive – 'Southern Image', the only dedicated dive boat at the Abrolhos (4 days/4 nights from Geraldton, max 8 divers, 3-4 dives a day); Eco Abrolhos Cruises – 5-day small-group cruises from Geraldton with snorkelling and diving; occasional Perth club charters. Batavia Coast Dive & Watersports (Geraldton) runs Abrolhos trips when boats are available. Scenic-flight day tours from Geraldton land on East Wallabi Island and include snorkelling at Turtle Bay (snorkel gear provided; no scuba).