Australia – Mount Gambier Sinkholes & Caves

The Lower South East of South Australia sits on limestone filled with groundwater, and around Mount Gambier it forms spring-fed ponds, sinkholes and flooded caves with exceptional visibility. Access is organised by the Cave Divers Association of Australia (CDAA), which grades divers (sinkhole, Basic Cave, Cave, Advanced Cave) and manages many private and public sites, together with SA Department for Environment and Water (NPWS SA) and ForestrySA permits. Piccaninnie Ponds is at the moment closed to diving until further notice, Ewens Ponds is open only on guided, accredited tours and closes 1 September–1 December each year, and most other sites need a CDAA rating and a booking. Only sites verifiable from CDAA, SA government or Wikipedia pages are included; several CDAA sites are left out because no reliable position could be found.

Facts

• Water temperature: Constant, roughly 14–18 °C year-round (a freediving operator at Kilsby quotes 14–15 °C).
• CDAA grades: CDAA lists sites as Unrated, Basic Cave, Cave and Advanced Cave; Piccaninnie Ponds additionally requires a sinkhole-category rating.
• Booking: DEW/NPWS SA sites: online booking, indemnity form, min. 2 divers, max 2 dives per day. ForestrySA sites: online permit and CDAA membership.

Season

• Best months: Dec, Jan, Feb, Mar, Apr
• Acceptable: May, Sep, Oct, Nov
• Poor: Jun, Jul, Aug
• Water temperature: 14–18 °C

Freshwater with near-constant temperature all year; summer (Dec–Mar) is more comfortable at the surface. Ewens Ponds is closed 1 Sep–1 Dec; ForestrySA sites close on Total Fire Ban days.

Dive sites (8)

Lower South East sinkholes & caves

• Engelbrecht Cave, Mount Gambier (CDAA Cave East / Advanced Cave West, permit) – advanced
• Ewens Ponds – guided & accredited tours only (closed 1 Sep–1 Dec) – 0–10 m, beginner
• Hells Hole, Caveton (ForestrySA permit, CDAA Basic Cave) – 0–25 m, advanced
• Kilsby Sinkhole (private land – CDAA Basic Cave rating / guided tours) – 0–37 m, advanced
• Little Blue Lake (CDAA Deep Cavern / Basic Cave rating) – 0–42 m, advanced
• Piccaninnie Ponds – The Chasm & Cathedral (DIVING CURRENTLY SUSPENDED) – 0–36 m, advanced
• Tank Cave, Tantanoola (CDAA-owned, Advanced Cave rating, permit) – advanced
• The Sisters Sinkhole, Mount Schank (NPWS permit, CDAA Basic Cave) – advanced

Operators (2)

• Kilsby Sinkhole (guided dives and tours) – dive centre, Moorak, near Mount Gambier (SA)
• Cave Divers Association of Australia (CDAA) – club, Mount Gambier region, South Australia

Cave and sinkhole diving here needs CDAA ratings and permits; closures and rules change (Piccaninnie Ponds is closed to diving until further notice, Ewens Ponds closes seasonally). Pages checked on 2026-10-29 may be out of date, always confirm with CDAA, NPWS SA or ForestrySA. Several positions are approximate. Never dive a cave beyond your training.