The Zoo is Bougainville Reef's most-loved dive site, and both marinelife.org.au and Dive the World say the name refers to the abundance and variety of animals. Marinelife.org.au gives a depth range of 5–40 m and a position of 15°30.317'S 147°06.890'E, and lists whitetip and grey reef sharks, surgeonfish, snappers, sweetlips, green and hawksbill turtles, nudibranchs and flatworms. Dive the World adds cowtail rays and schooling butterflyfish and unicornfish.

Bougainville is a small, isolated reef rising from deep water in the Coral Sea, roughly 230 km north-east of Cairns and 150 km south of Osprey. Like Osprey, its walls plunge into the abyss, and the clarity of the oceanic water is its trademark; visibility of 20–40 m is typical. The Zoo combines a reef slope and wall, so divers can choose between the deeper face and the fish-rich upper slope.

The experience is defined by quantity. Schools of butterflyfish, unicornfish, snapper and surgeonfish hang along the wall, grey reef sharks cruise the drop-off, whitetips rest on ledges, and turtles are common. Cowtail rays settle on sand patches in the upper reaches. For macro, nudibranchs and flatworms are plentiful on the reef surface. Hard and soft corals, sea fans and whips cover the slope.

The Zoo suits intermediate divers comfortable on a wall in blue water. Because Bougainville is visited less often than Osprey and gets only a day on most itineraries, crews often choose The Zoo as a banker dive. It is a good place to begin a Bougainville day before moving to the wrecks and caves elsewhere on the reef.

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.

The Zoo is dived from a mooring or tender drop at the published position (15°30.317'S 147°06.890'E).

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 20–25 m on the wall, move slowly along it watching for sharks and turtles, then rise onto the upper slope at 10–15 m where the fish schools concentrate and finish with a safety stop on the reef top.

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.