Great Barrier Reef

Cod Hole on the far northern Ribbon Reefs is legendary for its resident population of massive potato cod that approach divers with total confidence, sometimes reaching over a metre in length. The site is accessed mainly via liveaboard and sits at a comfortable 18 m maximum on a coral-rich reef plateau. Schools of barracuda, reef sharks, and vibrant soft corals round out one of the Coral Sea's most memorable dives.

Osprey Reef is a remote offshore atoll in the Coral Sea, accessible only by liveaboard, and North Horn is its crown jewel. The sheer wall plunges from the surface to beyond 800 m, draped with sea fans and black coral trees. Regular shark feeds have habituated grey reef, silvertip, and oceanic whitetip sharks, making this one of the premier shark encounters in the Indo-Pacific.

The outermost of the Ribbon Reefs, this site features a dramatic vertical wall on the ocean-facing side descending past 30 m, festooned with sea whips, gorgonians, and nudibranchs. The sheltered inner lagoon side is perfect for beginners with sandy slopes hosting garden eels and blue-spotted rays. Minke whale encounters are possible here between June and August.

The SS Yongala is widely regarded as one of the world's greatest wreck dives. This passenger steamer sank in a cyclone in 1911 and now rests at 14–30 m, completely encrusted with corals and teeming with giant grouper, bull sharks, sea snakes, and manta rays. Strong currents keep the site nutrient-rich and visibility high, but they also demand experience.

Cairns Deep Blue Diving offers daily trips to the Outer Barrier Reef aboard purpose-built catamarans, reaching world-class sites like Agincourt Reef and Flynn Reef. Specialising in both beginner courses and advanced technical dives, the team is expert in the coral-rich ecosystems of the Great Barrier Reef Marine Park. Guests frequently encounter reef sharks, sea turtles, and dense schools of tropical fish on every outing.

Reef Nomads is a boutique Port Douglas–based operator running small-group day trips and liveaboard charters to the remote ribbon reefs of the northern Great Barrier Reef. Their experienced guides specialise in manta ray encounters and coral bleaching recovery research, partnering with James Cook University on citizen-science programs. Nitrox and technical diving are available for qualified divers wanting to push deeper on the outer wall.