West White Beach Cave is technically a cavern rather than a cave: two large entrances separated by a central pillar lead into a massive chamber with plenty of space – 'no claustrophobia, guaranteed', as Diveplanit puts it. The Tourism Association lists it among the island's featured dives, and it is one of Diveplanit's highlighted sites.

The chamber sits at about 12 m. Its roof and walls are carpeted in colourful life – whip corals, sea fans, sponges and cup corals – and Divernet notes electric (disco) clams flashing in the recesses. Looking back towards the openings gives classic silhouette shots of divers against the blue. A torch is essential to bring out the colour inside, and a backup is strongly recommended.

Scientists surveying the island's submarine caves (Tan et al., 2014) found that the wide mouth, 15–20 m across, narrows to about 5 m and follows a fairly extensive system back into an anchialine zone with an obvious thermocline and halocline, home to rare crustaceans such as the hermit crab Pagurixus nomurai. That inner system is not part of the recreational dive.

Outside, exiting to the right, a colourful and lively reef at 12–18 m continues along the cliff before the wall drops into the blue with hard corals on its face, so the dive combines cavern and reef in one. Because there is no need to go deep, it works well as a second dive. It suits divers who are comfortable under an overhead but not ready for a true cave, and it is a great introduction to Christmas Island's karst.

Fly from Perth (about 4 hours, two to three flights a week, some via Cocos Islands) and hire a car – there is no public transport. Both dive centres are in The Settlement and launch their boats from the jetty/boat ramp at Flying Fish Cove, normally at about 8 am for a two-dive morning trip. From the cove the boat runs west and south-west along the north coast along the coast for roughly about 30 minutes to the cave just east of West White Beach.

There is no land access to the dive, and the vertical sea cliffs mean no exit other than the boat. Operators choose sites on the morning according to swell and wind.

On the exposed west coast, a long run from Flying Fish Cove, so it is only dived on calm days. The site is sheltered from the south-east trades (roughly May–November) but wide open to north-westerly monsoon swell (December–April) and to long-period south-west groundswell generated in the Southern Ocean, which wraps around Egeria Point. Operators generally need less than about 1–1.5 m of swell and light winds to make the trip; the calmest spell is usually August–November.

The west coast has a reputation for stronger and less predictable currents than the north, and for the clearest water on the island (often 40 m+). Visibility can drop during red crab spawning (Oct–Jan). Cyclone season is November–April.

Surge in the cavern with any swell.

Descend to the entrances at about 12 m, torches on, and explore the cavern chamber along its walls and roof, staying in sight of the openings. Exit to the right onto the reef at 12–18 m, follow it along, then ascend onto the shallows for the safety stop.

Cavern dive in the daylight zone; inner narrowing passage leads to an anchialine system – cave training, guideline and redundant lights required beyond the daylight zone.

CI Wet'n'Dry Adventures and Extra Divers Christmas Island – regular guided dive; often a second dive as it does not need depth.