Cave, Cavern & Sinkhole Dives in External Territories

From the Mount Gambier sinkholes to the Nullarbor caves and Christmas Island's sea caves. Many sites require cave-diving certification, permits or bookings; the technical notes on each page explain what is needed.

All states QLD NSW VIC TAS SA WA NT Territories

28 sites

Sort:Default Most dived Deepest Shallowest A–Z

WallMax 40 m

Admiralty (Osprey Reef)

Coral Sea · External Territory

A coral village of huge bommies with a centuries-old anchor in a swim-through, flashlight fish at night and a sheer…

Deep/Advanced + experienceIntermediate

WallMax 20 m

Amazing (Holmes Reef)

Coral Sea · External Territory

A shallow wall riddled with soft-coral-lined archways, swim-throughs and caves where sharks rest.

Advanced Open WaterIntermediate

ReefMax 21 mArea view

Black Bank

Norfolk Island · External Territory

Colourful boulder reef riddled with caves, arches and swim-throughs.

Advanced Open WaterBeginner

Cave/CavernMax 16 m

Boat Cave

Christmas Island · External Territory

A sea cave big enough to park the boat in, with a floor carpeted in plate corals and colourful whips on the walls.

Open WaterIntermediate

Cave/CavernMax 20 m

Coconut Point Cave

Christmas Island · External Territory

A documented submarine cave beneath the Coconut Point drift – a scientific and technical cave site, not a recreational…

Cave/Cavern certificationExpert/Technical

Pinnacle/BommieMax 21 m

Cooks Arch

Norfolk Island · External Territory

Swim through an arch in a 12 m-high rock that drops to 21 m, with caves and crevices nearby.

Advanced Open WaterIntermediate

Cave/CavernMax 22 m

Daniel Roux Cave

Christmas Island · External Territory

A sea cave that connects to one of the island's best-known land caves, with an anchialine pool and swiftlet colony…

Advanced Open WaterIntermediate

Cave/CavernMax 35 m

Dungeons & Dragons (Bougainville Reef)

Coral Sea · External Territory

A maze of caves and tunnels in the reef top, opening onto a 1,000 m wall patrolled by sharks and barracuda.

Deep/Advanced + experienceIntermediate

ReefMax 35 m

Fairy Grotto (Osprey Reef)

Coral Sea · External Territory

A range of big coral bommies with caverns and swim-throughs beside a 1,000 m wall.

Deep/Advanced + experienceIntermediate

WallMax 40 m

Fan Wall

Cocos (Keeling) Islands · External Territory

A wall with glorious fans, black trevally, cruising sharks and dogtooth tuna, plus a cave at 40 m for deep-experienced…

Deep/Advanced + experienceAdvanced

ReefMax 18 m

Fish Bowl (Nepean Island)

Norfolk Island · External Territory

Pretty cave-riddled reef with eight Galapagos sharks and close to 40 m visibility on Nigel Marsh's dive.

Open WaterIntermediate

ReefMax 40 m

Flora Reef

Coral Sea · External Territory

A tiny, rarely visited atoll with a sharp drop-off, silvertips and unusual lava-tube-like caves.

Deep/Advanced + experienceAdvanced

Pinnacle/BommieMax 30 mArea view

Johnnystone Rock

Norfolk Island · External Territory

Pinnacle from 2 m to 30 m with caverns, swim-throughs and enveloping coral.

Advanced Open WaterAdvanced

Pinnacle/BommieMax 24 m

Little Organ

Norfolk Island · External Territory

A huge arch and swim-through cave with a drummer school at the entrance and resident boarfish.

Advanced Open WaterIntermediate

Cave/CavernMax 25 m

Lost Lake Cave

Christmas Island · External Territory

Entrance zone of one of Christmas Island's largest submarine cave systems, with overhangs, gullies and light shafts.

Advanced Open WaterIntermediate

WallMax 18 m

Policemans Helmet

Norfolk Island · External Territory

Easy wall dive with overhangs beneath a helmet-shaped rock.

Open WaterBeginner

WallMax 40 mArea view

Rock Arch (Flinders Reef)

Coral Sea · External Territory

An arch, caves and a daylit cavern under a sheer south-west wall, with a ledge of big gorgonians at 40 m.

Deep/Advanced + experienceAdvanced

WallMax 30 m

Secret Caves (Osprey Reef)

Coral Sea · External Territory

Caves along Osprey's walls, especially good in the late afternoon and at night.

Advanced Open WaterIntermediate

WallMax 40 m

Silver City (Osprey Reef)

Coral Sea · External Territory

Silvertip sharks, volcano-shaped bommies and caves on a slope that ends at a 1,000 m wall.

Deep/Advanced + experienceIntermediate

WallMax 40 m

The Abyss (Holmes Reef)

Coral Sea · External Territory

A dramatic drift along a 1,000 m wall cut with caves, gutters and canyons.

Deep/Advanced + experienceAdvanced

WallMax 40 m

The Castles (Osprey Reef)

Coral Sea · External Territory

Coral turrets, gullies and fan-filled overhangs above a 1,000 m wall.

Deep/Advanced + experienceIntermediate

DriftMax 18 m

The Crack (Nepean Island)

Norfolk Island · External Territory

Drift along a bay of gutters and caves over a carpet of hard coral, with goldribbon cod, black cod and green turtles.

Advanced Open WaterIntermediate

Cave/CavernDepth not publishedShore

The Grotto

Christmas Island · External Territory

A tiny sea cave pool of crystal-clear, mixed fresh and salt water, 30 m from the road.

Snorkel/AnyBeginner

Cave/CavernMax 22 m

Thundercliff Cave

Christmas Island · External Territory

Swim into the cliff and surface inside air-filled chambers decorated with stalactites – reef, wall and cave in one dive.

Advanced Open WaterIntermediate

Cave/CavernMax 20 m

Thunderdome Cave

Christmas Island · External Territory

A hidden entrance to a dome-shaped cave and an extensive, twisting system with air pockets and formations – the…

Cave/Cavern certificationAdvanced

ReefMax 26 m

Turtle Cave (Holmes Reef)

Coral Sea · External Territory

Shallow bommies on sand at the Holmes overnight mooring – excellent visibility by day and a superb night dive.

Advanced Open WaterBeginner

WreckMax 25 m

Two Caves Wreck

Cocos (Keeling) Islands · External Territory

Broken-up remains of a Sri Lankan asylum-seeker boat – engines with a hull section beneath – on a reef with two caves.

Advanced Open WaterIntermediate

Cave/CavernMax 28 m

West White Beach Cave

Christmas Island · External Territory

A huge, bright sea cavern with twin entrances and a pillar, its roof and walls a riot of colour.

Advanced Open WaterIntermediate