Tank Cave is a world-class freshwater cave-diving and snorkeling site in the Limestone Coast of South Australia, lying beneath ForestrySA-managed land near Tantanoola. This flooded limestone cave system was carved over millennia by rainwater percolating through porous rock, creating crystal-clear underwater chambers, narrow passages, and cathedral-like caverns. Unlike open-water spots, Tank Cave offers an otherworldly experience of submerged stalactites, limestone formations, and near-perfect visibility in a completely enclosed environment. Access is strictly restricted to trained, certified cave divers who are members of the CDAA, with permits required from ForestrySA.
Tank Cave (Tantanoola)
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Wave Height 1.8 mSwell Period 10 sWind Speed 9.9 knPrecipitation 7.6 mmTidal Phase slack
Last evaluated
© Thom DevereuxDANGER: Explicit Risks Present
Tank Cave (Tantanoola) has hazards marked as danger. Entering the water here means you may face serious risks to your personal safety.
- Overhead Environment – No Direct Surface Access danger
Snorkeling and diving occurs entirely inside a submerged cave system with no direct ascent to surface. Entrapment and entanglement risks are extreme.
- Silt-Out / Zero Visibility danger
Fine sediment on cave floors can be easily stirred up, creating sudden complete loss of visibility, disorientation, and inability to find the exit.
- Restricted Entry – Qualified Divers Only danger
Access requires CDAA membership and advanced cave certification. Untrained snorkelers cannot enter due to the extreme overhead environment.
- Overhead cave environment danger
Sustained overhead environment with limited direct exit to surface, requiring cave-diving certification and training.
- Silt disturbance danger
Fine silt on cave floors can reduce visibility to zero if stirred up, leading to disorientation.
The spot
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Community contribution: submitted by Daniel
Know before you go
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High risk: Overhead Environment – No Direct Surface Access
Snorkeling and diving occurs entirely inside a submerged cave system with no direct ascent to surface. Entrapment and entanglement risks are extreme.
High risk: Silt-Out / Zero Visibility
Fine sediment on cave floors can be easily stirred up, creating sudden complete loss of visibility, disorientation, and inability to find the exit.
High risk: Restricted Entry – Qualified Divers Only
Access requires CDAA membership and advanced cave certification. Untrained snorkelers cannot enter due to the extreme overhead environment.
High risk: Overhead cave environment
Sustained overhead environment with limited direct exit to surface, requiring cave-diving certification and training.
High risk: Silt disturbance
Fine silt on cave floors can reduce visibility to zero if stirred up, leading to disorientation.
Moderate risk: Cold Water Temperature
The cave water remains consistently cold (around 12–15°C) year-round, increasing risk of hypothermia without appropriate exposure protection.
Moderate risk: Strong currents at restrictions
Narrow passages can channel water flow, creating unexpected current changes in cave tunnels.
Low risk: Limited daylight hours
Access to the cave is typically restricted to daylight hours and may be weather-dependent.
Wildlife Guide
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Gallery
3 photos from the community
Getting in
Snorkel tour
Entry
Located near Tantanoola, approximately 30 km north-west of Mount Gambier on the Limestone Coast of South Australia. Access is via ForestrySA-managed land off the Princes Highway. Exact cave entrance location is provided only to permitted CDAA members.
Parking & facilities
Limited unparked area near the ForestrySA access track. Not suitable for large vehicles or caravans without prior arrangement.
parking
A ForestrySA permit is required; fees vary and must be booked online via the ForestrySA Rezdy system. CDAA membership fees apply separately.
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Gallery ┬╖ 3 photos
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About this data
- Conditions last evaluated
- Spot data last updated
- Data sources
- Open-Meteo (marine & weather conditions), tide predictions via UTide, community contributors (descriptions, hazards, marine life).
- License
- Spot content licensed under CC BY-SA 4.0. How's the Spot is open source.
Weather & swell ┬╖ Open-Meteo marine & weather APIs Tides ┬╖ UTide harmonic analysis Sea & safety ┬╖ community reports