Nestled within the pastoral landscapes of South Australia’s Limestone Coast, just a short drive from Mount Gambier, lies the Kilsby Sinkhole—a mesmerizing destination for freediving enthusiasts.
Located just 10 kilometres south of Mount Gambier, South Australia, Kilsby Sinkhole sits on private land within a working sheep farm. Access is available strictly by prior booking, which can be arranged through their website.
Famed globally for its crystal-clear freshwater and expansive open caverns, Kilsby Sinkhole is a truly unique diving destination. It is the only site of its kind in Australia that welcomes everyone from snorkellers and Open Water certified divers to those with advanced Cave and Technical diving qualifications.
All snorkellers, freedivers, and Open Water divers must be accompanied by a certified dive instructor to ensure safety and preserve the site’s natural beauty.
Dropping to a depth of nearly 30 metres directly from the pontoon, Kilsby Sinkhole offers ideal conditions for freediving, with regular training camps held on site. The sinkhole also holds a fascinating past—it was once a classified location used for weapons research in the 1970s. Some of the original infrastructure from that era still remains, adding an intriguing layer of history to your visit.
For those wanting to immerse themselves in both luxury and nature, Kilsby Sinkhole now offers newly built, villa-style accommodation—perfect for a serene getaway beneath the stars and above the water.
A Freediver’s Dream
Kilsby Sinkhole boasts depths reaching up to 27 meters, providing an ideal environment for both novice and experienced freedivers. The sinkhole’s crystal-clear waters offer remarkable visibility, often extending up to 50 meters, allowing divers to fully appreciate the intricate limestone formations and the serene underwater ambiance .
A standout feature of the sinkhole is the captivating beam of light that penetrates its narrow opening, creating a “shard of light” effect. This natural illumination enhances the ethereal quality of the dive, offering a visual spectacle that is both awe-inspiring and unique to this location
Community and Marine Life
Adding to the sinkhole’s charm is its resident turtle, affectionately known as “Turtie.” Divers often encounter this friendly creature during their explorations, providing a delightful and memorable interaction that underscores the site’s vibrant ecosystem
Training and Retreats
Renowned freediving instructor Adam Stern has highlighted Kilsby Sinkhole as one of Australia’s premier freediving sites. Through his “Deep Week” programs, Stern offers comprehensive training sessions that cater to various skill levels, emphasizing both technique and safety in this unique underwater environment
Planning Your Visit
Access to Kilsby Sinkhole is regulated to preserve its pristine condition and ensure diver safety. Prospective visitors must book in advance through licensed diving operators. The site also offers accommodation options for those wishing to extend their stay and explore the surrounding attractions of Mount Gambier .
Whether you’re seeking to deepen your freediving skills or simply wish to experience the serene beauty of one of Australia’s natural wonders, Kilsby Sinkhole offers an unparalleled underwater adventure.
Training and Retreats
Several organizations offer structured freediving courses and retreats at Kilsby Sinkhole, catering to various skill levels:
Drifters Freediving: Provides AIDA-certified courses ranging from beginner to advanced levels, including retreats that focus on developing breath-hold techniques and underwater confidence.
OceanSense Freediving: Offers 5-day retreats combining freediving with guided breathwork, stretching, and meditation sessions, aiming to enhance both physical and mental aspects of diving.
The Pressure Project: Conducts immersive retreats that blend freediving with yoga and meditation, emphasizing relaxation and mental clarity underwater.
Environmental Considerations
Recent observations have indicated a drop in water levels at Kilsby Sinkhole, with a decrease of 1.5 meters recorded between January and March 2025. This decline is attributed to factors such as over-extraction of groundwater and reduced rainfall in the region. Efforts are underway to monitor and address these environmental challenges to preserve the sinkhole’s pristine condition for future generations.
