Dive sites · 2026 guide
Mount Gambier's freshwater sinkholes have some of the clearest water on earth, and Tasmania's Tasman Peninsula has spectacular sea caves. Many freshwater sites need Cave Divers Association of Australia (CDAA) ratings or permits, and some are open-water sinkholes any certified diver can visit.
Overhead environments are unforgiving — only enter caves with the training the site requires.
1South West Rocks, New South Wales
Grey nurse shark aggregation and one of Australia's few genuine ocean through-caves.
The cave has a deeper entrance around 24 metres and rises internally toward shallower water before reaching the opposite side. That makes it a genuine through-cave rather than a cavern, which is unusual in an ocean setting.
Look for: Grey Nurse Shark, Wobbegong
Full Fish Rock guide →
2Tasman Peninsula & Eaglehawk Neck, Tasmania
An enormous dolerite sea cave on the Tasman Peninsula, large enough to surface inside.
The dolerite columns that form the highest sea cliffs in the Southern Hemisphere continue underwater here, producing vertical walls, caves and architecture that is genuinely unusual.
Look for: Giant Kelp Forest
Eaglehawk Dive Centre3Mount Gambier, South Australia
A limestone sinkhole with water so clear the experience is closer to flying than diving.
The visibility is the point. With clarity that can exceed anything in the ocean, divers hanging mid-water can see the full dimensions of the chamber, and shafts of sunlight through the entrance produce the images the site is known for.
Look for: Very little — these are oligotrophic freshwater systems with minimal life, which is part of why the water is so clear.
4Rottnest Island, Western Australia
Limestone caverns, swim-throughs, ledges and walls 18 kilometres off Fremantle.
Marine life reflects a warm-temperate mix influenced by the Leeuwin Current, which brings tropical species considerably further south than the latitude would suggest.
Look for: western blue gropers, tropical and temperate fish together, coral growth at high latitude, crayfish, rays
Full Rottnest Island guide →5Tasman Peninsula & Eaglehawk Neck, Tasmania
Dolerite walls, sea caves and giant kelp beneath some of Australia's highest sea cliffs.
Sponge gardens cover the walls in dense colour, and giant kelp grows in the shallower areas where it remains.
Look for: Giant Kelp Forest
Eaglehawk Dive Centre6Mount Gambier, South Australia
Three shallow spring-fed ponds connected by channels — a drift dive through crystal-clear freshwater.
Because the ponds are shallow and open to the sky, the site does not require cave qualification, though a permit is needed and access is time-limited.
Look for: dense aquatic vegetation, freshwater crayfish, small native fish, Very limited compared with marine sites
7Mount Gambier, South Australia
A karst spring of extraordinary clarity, with the Cathedral chamber and a chasm beyond 100 metres.
The main features are the First Pond, the Cathedral — a white limestone chamber — and the Chasm, which descends beyond 100 metres.
Look for: Minimal — freshwater karst systems support very little life, which contributes to the clarity.
8Mount Gambier, South Australia
One of the longest underwater cave systems in Australia — advanced CDAA qualification only.
It is restricted to divers holding the highest CDAA qualification categories, and access requires both that qualification and landowner permission.
Look for: Effectively none — this is a freshwater cave system.
Sites are chosen from our dive-site database and ordered by how well documented they are: flagship status, the number of operators we have confirmed dive there, and the marine life recorded. Nobody pays to be listed.
No. Listings and order come from our research only. Businesses can ask us to correct their details, but not to change their position.
It is generated from the directory's latest research, checked in 2026. Conditions, operators and seasons change — confirm details with the operator before you book.
