Oyster Stacks is a compact, fish-packed snorkel site where four or five large rock formations, encrusted with oysters and coral, rise from the sand just off a rocky shore in Cape Range National Park. It is one of the most popular spots on the Ningaloo coast because the life is concentrated in a small area within a short swim of the car park.

The stacks and the coral between them shelter a dense community of reef fish — damsels, butterflyfish, wrasse, parrotfish and angelfish — with reef sharks, stingrays, turtles, starfish and sea urchins regularly seen. Plate corals grow around the bases. Because everything is within a few metres of the surface, it is ideal for photographers and families with confident swimmers.

The site is entirely tide-dependent. It should only be snorkelled on a tide higher than about 1.2 m, within roughly two hours of high water; at lower tides the tops of the stacks are exposed, snorkellers scrape over coral and oysters, and the reef suffers. Entry is over rocks, so reef shoes are strongly recommended. It can be crowded in the permitted windows, and the water can be bumpy when the wind is up.

Outside the stacks, currents can pick up, but around the formations the water is generally calm. It suits beginners and anyone wanting a shallow, fish-dense snorkel.

Planning a Cape Range day: the national park's lagoon sites stretch about 50 km along Yardie Creek Road from Tantabiddi to Osprey and Sandy Bay, all within the World Heritage-listed Ningaloo Coast. The reef crest sits a few hundred metres to a couple of kilometres offshore, enclosing a lagoon of sand, seagrass and coral bommies, and a series of sanctuary zones (look but don't take) protect the best-known snorkel areas. There are no shops, fuel or air fills in the park, so bring water, food, sun protection and reef shoes from Exmouth. The Milyering Discovery Centre has current information on conditions and zones. Mornings are usually calmer, clearer and cooler than afternoons, and checking the tide chart is essential for the shallower sites.

From Exmouth drive into Cape Range National Park via Yardie Creek Road (park fee), about 65 km and 50 minutes. The Oyster Stacks car park is just north of Osprey Bay campground. A short path leads to the rocky shoreline; wear reef shoes to cross the rocks and ease into the water.

The stacks begin only a few metres from shore. Go within about two hours either side of a high tide above 1.2 m — at lower tides the water is too shallow and snorkellers damage the coral and themselves.

Cape Range lagoon sites are protected by the reef crest, but a south-westerly swell pumps water over the reef and out through the gaps, strengthening currents in the lagoon, particularly on a high tide and big swell. The afternoon south to south-westerly sea breeze (often 15–25 knots from spring to autumn) makes the water choppy and reduces visibility, so mornings are best. Summer air temperatures exceed 40 °C; cyclone season is November–April.

Irukandji and other stinging jellyfish occur mainly in the warmer months and autumn. Visibility in the lagoon is usually 5–15 m.

Snorkel site. Check the tide chart and arrive for a high tide above 1.2 m. Enter carefully from the rocks, float over the stacks without standing on them, and circle each stack looking into the gaps and under ledges.

Stay within the stacks area, where current is minimal, and exit the way you came in.

Independent shore snorkel; no operator needed. Exmouth dive shops hire snorkel gear and some tour companies include lagoon snorkels on Cape Range day trips.