Depth is the number every diver asks first, and in Australia it runs from a 124 m sinkhole under a South Australian paddock to the 200 m dumping ground off Rottnest. Almost everything on this list is technical territory: decompression, mixed gas, cave or deep wreck training, and a local operator or club that knows the site.
The ranking is by the recorded maximum depth of the site. Many of these have shallower sections that recreational divers can enjoy; the site pages say where.
Updated daily from the directory. 25 sites listed.
1. Norfolk Island · External Territory
Pel-Air Westwind wreck
Max depth: 54 m · Largely intact Westwind medevac jet at 48 m from the 2009 night ditching in which all six aboard survived.
2. Coral Sea · External Territory
Admiralty (Osprey Reef)
Max depth: 40 m · A coral village of huge bommies with a centuries-old anchor in a swim-through, flashlight fish at night and a sheer wall below.
3. Coral Sea · External Territory
Crystal Plateau (Bougainville Reef)
Max depth: 40 m · A clear-water hard-coral terrace on the edge of the abyss, with sharks and giant potato cod.
4. Coral Sea · External Territory
False Entrance (Osprey Reef)
Max depth: 40 m · Spectacular bommies and blue-water swim-throughs in a blind gully, with schooling trevally and barracuda and dense grey reef shark aggregations.
5. Coral Sea · External Territory
Half Way Wall (Osprey Reef)
Max depth: 40 m · Osprey's gentler wall, with bommies on the lip of a 1,000 m drop and the chance of hammerheads.
6. Coral Sea · External Territory
North Horn (Osprey Reef)
Max depth: 40 m · The Coral Sea's signature shark dive on a seamount wall.
7. Coral Sea · External Territory
North Horn Wall (Osprey Reef)
Max depth: 40 m · A sheer drift along a wall dropping more than 1,000 m, with caves, overhangs, mantas and tuna.
8. Christmas Island · External Territory
Perpendicular Wall
Max depth: 40 m · A true vertical wall into the abyss at the island's north-western tip, with colourful fans, schooling fish and a real chance of sharks, mantas and whale sharks.
9. Coral Sea · External Territory
Silver City (Osprey Reef)
Max depth: 40 m · Silvertip sharks, volcano-shaped bommies and caves on a slope that ends at a 1,000 m wall.
10. Cocos (Keeling) Islands · External Territory
Ski Run
Max depth: 40 m · A sand chute from the reef edge down to a glassfish-covered bommie hunted by trevally, with whitetips and extra-long garden eels on the sand.
11. Coral Sea · External Territory
The Castles (Osprey Reef)
Max depth: 40 m · Coral towers on the Osprey drop-off with pelagics passing in blue water.
12. Coral Sea · External Territory
Between the Wrecks (Bougainville Reef)
Max depth: 40 m · A clear-water wall drift between Bougainville's two freighter wrecks.
13. Coral Sea · External Territory
Cathedral (Holmes Reef)
Max depth: 40 m · A deep Holmes Reef wall where a golden anthias species was first recorded in Australia, with sharks, tuna and potato cod.
14. Christmas Island · External Territory
Chicken Farm
Max depth: 40 m · A vertical north-coast wall with exceptionally large gorgonian fans below 33 m.
15. Coral Sea · External Territory
Cod Wall (Flinders Reef)
Max depth: 40 m · Flinders Reef's potato cod wall, far from the day-boat crowds.
16. Coral Sea · External Territory
Coral Canyons (Osprey Reef)
Max depth: 40 m · A network of coral canyons leading to the edge of a drop of more than 1,400 m, with schooling jacks and reef sharks.
17. Cocos (Keeling) Islands · External Territory
Fan Wall
Max depth: 40 m · A wall with glorious fans, black trevally, cruising sharks and dogtooth tuna, plus a cave at 40 m for deep-experienced divers.
18. Coral Sea · External Territory
Golden Wall (Holmes Reef)
Max depth: 40 m · A sheer wall glowing with golden sea whips and gorgonians, with pelagic schools off the edge.
19. Coral Sea · External Territory
Middle Earth (Bougainville Reef)
Max depth: 40 m · A rarely described Bougainville drift site on Mike Ball's Far Northern expedition.
20. Coral Sea · External Territory
Nautilus Wall (Osprey Reef)
Max depth: 40 m · A wall named for Osprey's isolated dwarf nautilus population, historically the site of dawn nautilus releases for photographers.
21. Coral Sea · External Territory
Rapid Horn (Osprey Reef)
Max depth: 40 m · A rarely dived, current-swept southern horn with dense fish schools on the plateau and a sheer wall.
22. Norfolk Island · External Territory
South Rock (Phillip Island)
Max depth: 40 m · Current-swept pinnacle to 40 m off Phillip Island, with black coral and abundant fish.
23. Coral Sea · External Territory
The Abyss (Holmes Reef)
Max depth: 40 m · A dramatic drift along a 1,000 m wall cut with caves, gutters and canyons.
24. Coral Sea · External Territory
The Sticks (Bougainville Reef)
Max depth: 40 m · A clear-water wall drift with sharks, rays and schooling fish.
25. Coral Sea · External Territory
The Zoo (Bougainville Reef)
Max depth: 40 m · Bougainville's signature site, crowded with sharks, turtles and schooling reef fish in clear oceanic water.
The guide
How to read this list
Maximum depth is the number a database can sort by, but it is not what makes these sites hard. Three things are: the environment (open ocean over 80 m, a sinkhole shaft, a tidal channel), the logistics (a boat that can find and hold a mark, a permit, a cave rating) and the distance to a chamber. Almost everything above 60 m on this list is dived by a small circle of technical divers and clubs, on rebreathers or open-circuit trimix, in specific weather windows.
The recreational reader should look at the shallow ends. Piccaninnie Ponds, Kilsby and Ewens Ponds put Open Water divers over water that is 60 to 100 m deep without taking them past 20 m. The Kanowna and Federal have no shallow options, but the Port Phillip Heads walls that lead down to Trimix Corner start at 12 m.
Where the deep water is
Victoria dominates. Bass Strait is shallow but the shipping lane past the Heads, Cape Schanck and Cape Otway has claimed liners, colliers and warships in 70 to 115 m, and Melbourne has the most active technical wreck community in the country to find them. South Australia's Limestone Coast supplies the sinkholes: the Shaft, the Chasm and a dozen deep cave systems, all managed by the CDAA. Western Australia has the Rottnest graveyard and the Nullarbor caves; New South Wales has the Fairwind and a run of 60 m-plus wrecks off Sydney and South West Rocks.
Queensland barely features, which surprises people. The reef is shallow, the deep walls of the Coral Sea drop from 20 m to 1,000 m without a floor to record, and the state's deep wrecks (the Yongala at 30 m, the Brisbane at 28 m) are recreational. Deep in Queensland means offshore, not down.
Training and access
Below 40 m is technical diving by every agency's definition: decompression procedures, redundant gas, helium below 50 to 60 m. The sinkholes add CDAA ratings (Deep Cavern, Cave, Advanced Cave), most of which take years. Many of the wrecks are protected historic shipwrecks or war graves with permit systems run by the state heritage office; the site pages say which. The technical diving section explains the courses, and the courses directory lists the centres that teach them.
Editorial last reviewed September 2026. The list itself is regenerated from the directory daily.
Frequently asked questions
What is the deepest dive site in Australia?
Rottnest's Ships' Graveyard holds wrecks down to 200 m, dived only by technical teams. The deepest sinkhole is the Shaft near Mount Gambier at 124 m; the deepest commonly dived wrecks are the Kanowna (82 m) off Wilsons Promontory and the Nord (42 m) in Tasmania.
How deep can a recreational diver go?
Recreational agencies cap depth at 40 m with the Deep Diver specialty, 30 m with Advanced Open Water and 18 m with Open Water. Beyond 40 m is technical diving.
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