Meet the site
Big Brother is the companion site to Little Sister on the corners of the Third and Fourth Sister reefs off Tongue Reef. Wavelength Reef Cruises describes both corners together: very good coral cover from large boulder corals to patches of branching corals and huge clams, with numerous reef fish and larger pelagic species, especially very large barracuda keeping station over the deeper boulder corals. Corner sites benefit from water exchange as the tide sweeps past, and Big Brother is no exception. The flow keeps the water clear and feeds the corals and fish. Boulder corals form massive mounds, branching corals form thickets, and giant clams nestle among them. The fish life includes schooling fusiliers, parrotfish, wrasse and butterflyfish, with pelagic visitors such as barracuda, trevally and reef sharks. Wavelength does not publish separate details for Big Brother beyond the shared description, so the two sites should be expected to be similar in character. No depth figures are published; the snorkel area is shallow. Like the other Sister reef moorings it lies on the seaward side of Tongue Reef, about 90 minutes from Port Douglas, in a low-impact area with exclusive operator access, so it is never crowded. Wavelength is a snorkel-only operator whose marine biologists guide in-water tours and give reef talks; its skipper chooses three sites each day from the company's exclusive moorings according to wind and tide, so a particular site is never guaranteed. Scuba divers wanting to dive the Sister reefs need a private charter, and because the site names are Wavelength's own, other operators may not recognise them.
What you might see
Large barracuda, trevally, reef sharks, giant clams, boulder and branching corals, fusiliers, parrotfish, wrasse, butterflyfish
Location
A reef corner on the Third/Fourth Sister reefs off Tongue Reef, paired with Little Sister, with good coral and large pelagic fish.
Facilities nearby
Departs Crystalbrook Superyacht Marina, Wharf Street, Port Douglas – car parking, toilets, cafes and restaurants at the marina; dive shops in town for gear hire and air
Before you make plans
Conditions, access and operator schedules can change. This is a location guide, not a dive plan. Ask a local operator about current conditions and suitability for your training and experience.
Sources & further reading
wavelength.com.auRecord updated 26 Sept 2026. Source claims are being reviewed.