Crystal Plateau is Mike Ball's go-to site at Bougainville and appears on almost every Coral Sea itinerary it runs. Mike Ball describes a reef terrace of hard corals at 20–30 m that descends into an abyss hundreds of metres deep, with sea fans, soft corals and patrolling sharks. Its Coral Sea Odyssey materials add giant potato cod.

The name reflects the site's two defining features: a flat plateau of reef and the crystal-clear oceanic water that surrounds Bougainville. The terrace is carpeted in hard corals, plate and branching forms among them, and sea fans and soft corals grow toward its edge, where the reef falls away into deep blue water. Divers can cruise across the terrace, pause at the rim to look down the wall, and watch for pelagic visitors.

Grey reef and whitetip sharks patrol the edge, and potato cod, some very large, cruise the plateau and approach divers much as they do at the Cod Hole. Marinelife.org.au also notes giant potato cod. The usual Coral Sea cast of trevally, snapper, surgeonfish, butterflyfish, triggerfish and anthias is abundant, and turtles pass through.

Because the terrace is at 20–30 m, the dive is moderately deep and bottom times are limited on air; nitrox helps. It suits intermediate divers comfortable at that depth with a wall close by. The combination of healthy hard coral, big cod and sharks in very clear water makes it a strong introduction to Bougainville, and it pairs well with the caves at Dungeons & Dragons and the Antonio Tarabocchia wreck on the same day.

Liveaboard only. Mike Ball's Spoilsport visits Bougainville on its 4-night Osprey fly-dive (Cairns departure Thursday evening, return by flight from Lizard Island), 5-night Coral Sea & Cod Hole and 7-night Coral Sea expeditions; the overnight run from Cairns is roughly 230 km of open ocean. Bougainville is not guaranteed on every itinerary and is usually allocated one day.

Crystal Plateau is on Mike Ball's 4-night Osprey, 5-night Coral Sea & Cod Hole, 7-night Coral Sea and Coral Sea Odyssey itineraries and is dived from a mooring.

Bougainville is a small, isolated Coral Sea reef about 230 km north-east of Cairns and 150 km south of Osprey, with no land to shelter behind, so the surface can be choppy in any SE trade wind over about 20 knots, common June to August. Conditions broadly follow Osprey's, though Bougainville is sometimes calmer when Osprey is windy. Currents are generally mild but can pick up on the corners and walls.

September to December usually gives the calmest seas and best visibility (20–40 m); December to April is cyclone season.

Descend to the terrace at 20–25 m, cruise across the hard corals toward the edge, look over into the abyss for sharks, and watch for the giant potato cod. Ascend back across the terrace to the reef top for the safety stop.

Nitrox recommended to extend bottom time on the 20–30 m terrace.

Mike Ball Dive Expeditions (Spoilsport) – 4-night Osprey fly-dive, 5-night Coral Sea & Cod Hole and 7-night Coral Sea expeditions from Cairns; Bougainville included on most Coral Sea departures when weather allows. One of the most regularly scheduled Bougainville sites.