Meet the site
Kilsby Sinkhole is the one Mount Gambier sinkhole that ordinary Open Water divers can reliably get into, and it is the site most visiting divers remember. The hole is a large collapse doline in Oligocene limestone, walled by vertical grey cliffs hung with ferns and ivy, on a sheep property that five generations of the Kilsby family have farmed. From the pontoon the water drops away in a sheer, clear column – visibility of 50 m is normal and it is often more, so you see the whole bowl of the sinkhole from the surface. Below the lip a slope of rock and silt leads down into the main basin, and a crystal-clear flooded chamber opens off the south-western side, where daylight fades into blue. The upper few metres carry filamentous algae and aquatic weed that glow green in the midday sun, and light shafts pierce the water between about 11 am and 2 pm.
The site has an unusual history. It began as a stock watering hole, was one of Mount Gambier's pioneering dive sites in the 1960s, and was closed after a drowning in 1969. It reopened to civilian divers in 1983, has been used as a training site for SA Police divers and – according to the owners – as a centre for secret weapons research, with the depth and clarity making it ideal for underwater testing. A 2007 lease between the family and the CDAA extended access times and permitted deeper dives on trimix.
Today the Kilsbys also run snorkel tours, dry sinkhole tours, accommodation and gin tastings, so expect other visitors on the rim. For Open Water divers the dive is essentially an introduction to sinkhole diving in a controlled, daylight setting – neutral buoyancy over a bottomless-looking drop is the skill it teaches. CDAA Basic Cave divers use it for deeper, longer dives and photography, and technical divers use it for trimix training. It suits anyone with good buoyancy who wants to see what 'gin-clear' actually means.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
Kilsby Sinkhole is recorded as Sinkhole/Cenote in Mount Gambier Sinkholes & Caves. The listed access is shore. Confirm the actual meeting point, route and permission to visit; a map pin does not establish any of these.
Topics flagged by the stored research
These are questions prompted by the existing notes, not a verified or complete hazard assessment.
- Planned depth
- Confirm the intended route and training requirements; the recorded maximum is not a target.
Historical access notes exist for this record, but have not been independently verified for current use. Request current directions from the operator or site manager rather than following an old entry description.
Questions, answered
Is Kilsby Sinkhole suitable for my certification?
The record lists Technical (decompression). That does not establish suitability for every route or day. Share your training, recent experience and equipment needs with the operator and ask about the specific proposed dive.
Can I book Kilsby Sinkhole through YouDive?
YouDive is an independent research directory. Contact an operator directly to confirm whether it currently runs the trip, the inclusions and the booking terms.
What you might see
Very little fish life; freshwater shrimp, yabbies, small native fish near the weed, filamentous algae and aquatic plants in the daylight zone
Location
A large, cliff-walled flooded sinkhole on the Kilsby family sheep farm at Moorak, about 14 km (15 min) south of Mount Gambier; a chamber extends off the south-western side.
Facilities nearby
Parking at the rim, pontoon at water level, toilets and on-site accommodation (villas); gear fills and hire from Dive Experience in Mount Gambier; cafes and supermarkets in Mount Gambier.
Before you make plans
Conditions, access and operator schedules can change. This is a location guide, not a dive plan. Ask a local operator about current conditions and suitability for your training and experience.
Sources & further reading
kilsbysinkhole.comkilsbysinkhole.comkilsbysinkhole.comcavedivers.com.audive-experience.rezdy.comen.wikipedia.orgRecord updated 27 Sept 2026. Source claims are being reviewed.