Kilsby Sinkhole Freediving: What You Need to Know Before Your First Visit
An independent guide to Australia's most famous freediving training destination — what to expect, how to prepare, and what questions to ask.
If you're researching freediving courses in Melbourne, you've probably seen Kilsby Sinkhole mentioned. Many providers offer courses or retreats that include dives at this legendary South Australian site, and for good reason: it's genuinely one of the best places on the planet to learn and practice freediving.
What Is Kilsby Sinkhole?
Kilsby Sinkhole is a flooded limestone sinkhole located on a working sheep farm about 14 kilometres south of Mount Gambier in South Australia. It's approximately a 5-hour drive from Melbourne — far enough to require planning, close enough for a long weekend trip.
The Numbers
Visibility: 40-50+ metres (often described as "limitless")
Recreational depth: 24-27 metres from the pontoon
Total depth: 60+ metres (cave sections, restricted access)
Water temperature: Approximately 14°C year-round
Water type: Fresh (not salt water)
Why It's Special
Crystal-clear water: The visibility is genuinely remarkable. You can see the surface from 25 metres depth. Light beams penetrate deep into the water column, creating ethereal conditions for training and photography.
Controlled environment: No currents, no waves, no surge, no marine life that might distract or concern you. It's as close to a controlled training environment as open water gets.
Vertical profile: The depth drops away directly from the pontoon, making it ideal for depth training without long surface swims or boat logistics.
Consistent conditions: Unlike ocean diving where conditions vary daily, Kilsby offers predictable, stable conditions year-round.
Why Melbourne Courses Use Kilsby
Learning Benefits
Visibility aids learning: When you can clearly see your instructor, the line, and your own body position at depth, learning is dramatically easier than in murky conditions.
No variable management: In the ocean, instructors must manage students while also monitoring currents, visibility changes, marine life, boat traffic, and weather. At Kilsby, they can focus entirely on your technique and safety.
Confidence building: Descending into crystal-clear water is psychologically easier than dropping into murky ocean. Many students achieve deeper dives at Kilsby than they would initially manage in the ocean.
Practical Considerations
Reliability: Ocean conditions in Melbourne can force course postponements. Kilsby rarely does.
Depth access: The vertical profile provides easy access to training depths without boat logistics.
Accommodation: On-site villas allow multi-day immersive training experiences.
What to Expect at Kilsby
Access and Facilities
Kilsby Sinkhole is on private land and access is strictly controlled through licensed operators. You cannot simply turn up — all visits must be arranged through an approved provider.
Access via a ramp, steps, and ladders down to water level
A pontoon provides the primary entry/exit point
Villa-style accommodation available
BBQ area and fire pit
The sinkhole has its own gin (Sinkhole Gin) — available for post-dive enjoyment
The Diving Experience
Your first view: Walking up to Kilsby, you're on a sheep farm. Paddocks, sheep, rural Australia. Then suddenly, there's this otherworldly blue pool. The contrast is part of the magic.
Underwater: The visibility is genuinely stunning. You can look up and see clouds through the water. Light beams stream down like something from a film.
The resident turtle: Kilsby has a resident freshwater turtle (affectionately called "Turtie") that often appears during dives.
What's Different from Ocean Diving
Buoyancy: Freshwater is less dense — you'll need less weight than in the ocean
No marine life (mostly): Unlike ocean diving, minimal marine life to observe
Temperature stability: The 14°C water is consistent throughout depth
Adjustment required: Skills learned at Kilsby need some adjustment when returning to ocean conditions
Nearby Dive Sites
Little Blue Lake: A volcanic lake with depths exceeding 35 metres, offering additional depth training opportunities.
Ewens Ponds: A series of spring-fed ponds with crystal-clear water and unique aquatic vegetation.
Port MacDonnell: Known as the Southern Rock Lobster capital of Australia. Some courses include ocean diving here.
Preparing for a Kilsby Trip
Physical Preparation
Access requirements: Entry/exit involves stairs and ladders — discuss mobility limitations with your provider beforehand
Cold water readiness: 14°C requires appropriate exposure protection (5mm minimum, 7mm or open-cell preferable)
Fitness: Being reasonably fit makes the experience more enjoyable
What to Bring
Usually provided: Freediving equipment (mask, fins, snorkel, weights), sometimes wetsuits
Usually bring yourself: Wetsuit if not provided (5mm minimum), warm clothes for between dives and evenings, swimsuit, towels, toiletries, camera if desired
For the drive: Plan for 5+ hours each way from Melbourne, entertainment/podcasts, snacks, fuel stops
Questions to Ask Your Provider
About the Kilsby Component
How many dives at Kilsby are included?
What depths will we be working at?
Will we also dive Little Blue Lake or other sites?
About Logistics
Is accommodation included? If so, where?
How do we get to Kilsby — drive ourselves, convoy, or transport provided?
What meals/food are included vs. self-catered?
About Equipment
What equipment is provided vs. what should I bring?
Is wetsuit hire included? What thickness?
Is a Kilsby Course Right for You?
Kilsby courses work well if:
You want the best possible conditions for learning
You can commit the time for travel and multi-day format
You value photography opportunities
Budget allows for the typically higher cost
Consider local-only courses if:
Time is very limited
Budget is a major constraint
You specifically want to learn in ocean conditions
Travel to Mount Gambier isn't feasible
After Kilsby: Transitioning to Ocean Diving
If your first depth training is at Kilsby, some adjustment is needed when you move to ocean diving:
Buoyancy changes: Saltwater is denser — you'll need more weight in the ocean
Visibility adjustment: Going from 40+ metre visibility to typical Melbourne conditions (6-10m) is significant
Environmental awareness: Ocean diving requires awareness of currents, swell, marine life, and boat traffic
Recommended transition:
Start with protected shore sites (pier diving)
Dive conservatively, well within your Kilsby-demonstrated depths
Build ocean experience progressively
Final Thoughts
Kilsby Sinkhole is genuinely special. The visibility, the light, the otherworldly environment — it delivers an experience unlike typical ocean diving. For learning freediving, the controlled conditions and clear water create an ideal classroom.
If you have the opportunity to include Kilsby in your freediving education, it's worth serious consideration. Just go in with realistic expectations: it's not a magic solution, but it is an exceptional training environment.
And the light beams really are as beautiful as the photos suggest.