Meet the site
Boat Cave is exactly what the name says: a sea cave in the north-west cliffs big enough for a small boat to shelter in, and the operators sometimes moor the dive boat inside it. Extra Divers describe it as equal parts reef and adventure, with a depth range of 4–16 m and a torchlit finale in the cave.
The cave has an above-water section extending back into the cliff, and a floor at about 8–10 m that is completely covered in plate corals, angled towards the entrance to catch the light (Diveplanit, Divernet). The walls and ceiling carry red, pink and yellow whip corals and other colourful invertebrates, which come alive in torchlight. It is shallow and roomy enough that most divers feel comfortable, and the light from the entrance is always visible.
Outside, the reef along the base of the cliff has healthy hard corals and plenty of reef fish, and the blue beyond brings pelagics: Extra Divers mention wahoo and turtles, and the north-west corner of the island is known for passing sharks, dolphins and, in the wet season, whale sharks. Most dives spend the first part on the reef and finish in the cave.
Boat Cave is an easy introduction to Christmas Island's sea caves, suited to divers with basic buoyancy skills who want a taste of the island's karst without committing to Thundercliff or Thunderdome. It is on the more exposed north-west part of the coast, near Perpendicular Wall, and needs calm conditions. Photographers enjoy the plate-coral floor framed by the cave mouth.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
Boat Cave is recorded as Cave/Cavern in Christmas Island. The listed access is boat. Confirm the actual meeting point, route and permission to visit; a map pin does not establish any of these.
Topics flagged by the stored research
These are questions prompted by the existing notes, not a verified or complete hazard assessment.
- Other water users
- Ask about vessel activity, exclusion areas and the agreed surface arrangements.
- Water movement
- Ask how swell and local exposure affect the proposed entry, exit and route.
- Overhead environments
- Ask whether the plan stays entirely in open water. A wreck or cave listing is not permission or training to enter.
Historical access notes exist for this record, but have not been independently verified for current use. Request current directions from the operator or site manager rather than following an old entry description.
Questions, answered
Is Boat Cave suitable for my certification?
The record lists Open Water. That does not establish suitability for every route or day. Share your training, recent experience and equipment needs with the operator and ask about the specific proposed dive.
Can I book Boat Cave through YouDive?
YouDive is an independent research directory. Contact an operator directly to confirm whether it currently runs the trip, the inclusions and the booking terms.
What you might see
Plate corals, red, pink and yellow whip corals, wahoo, turtles, reef fish, reef sharks, spinner dolphins, whale sharks (seasonal)
Location
A sea cave on the north-west coast large enough for a small boat to shelter in, with a plate-coral floor at 8–10 m; reef outside.
Facilities nearby
Departs Flying Fish Cove jetty/ramp.
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
extradivers.com.audiveplanit.comdivernet.comRecord updated 26 Sept 2026. Source claims are being reviewed.