When you start your scuba diving journey, you’re excited to just have the chance to breathe underwater. You fumble around with your gear, try to remember bits and pieces of the theory and not get overly excited when a big marine animal passes by. Everything feels like information overload and a huge stimulus. It’s hard to consider anything more extreme when open water diving already feels exactly that.
However, as you start to love diving even more, and progress deeper into the sport, things change. With more dives comes more experience, as well as making friends who love scuba as much as you do. Continuing your education often further drives curiosity. And that curiosity starts taking you to places you never thought you’d go. Places you once thought were reserved only for the explorers, the adventure seekers, the cave divers of this world. But soon enough you realize that you ARE one of those people, and scuba diving was your ticket to this underground.
This is exactly how I felt when I arrived at a town called Mt. Gambier in South Australia. I had no idea what I was getting myself into, but I was about to find out by diving headfirst into the deep end. Known as a notorious congregation spot for extreme cave divers, this area is made up of sinkholes and intricate underground systems that have yet to be fully discovered.
Famous expert-level cave divers—Richard Harris and Craig Challen—are known to frequent these parts. If you don’t know them, they are the men who led the mission to save the 12 children who were trapped in a flooded cave system in the heart of Thailand.
Coincidentally, they had been on site the week before our team arrived in South Australia, and we missed them by a single day. But we were still in luck—as we had the chance to meet a few notorious cave explorers who call the Mt. Gambier region their home.
What is Cave Diving
Before I get to that, let’s talk a bit about cave diving more generally. It’s a highly specialized form of scuba diving that takes place in underwater cave systems—and it’s regarded as one of the most challenging and extreme activities within the diving world.
Unlike open-water, cave divers venture into submerged passageways, often in complete darkness, relying solely on their equipment and training. The environments cave divers encounter can be unforgiving, with narrow passages, low visibility, strong currents and complex topography.
The absence of natural light adds an additional level of difficulty, requiring cave divers to use torches and their past knowledge of any given cave system. The risks associated with cave diving include entanglement, disorientation, gas supply failures, as well as potentially catastrophic accidents.
Cave diving demands a high level of skill, experience and mental fortitude. It requires extensive certification beyond standard scuba diving training. Cave divers must possess exceptional buoyancy control, navigation skills and the ability to remain calm under stressful conditions. They must also be proficient in gas management and carry redundant equipment to ensure safety in case of equipment failure.
Due to the inherent risks involved, proper planning and preparation are crucial in cave diving as well. Divers often use guidelines or reels to maintain a continuous connection to the entrance of the cave, ensuring a safe exit route.
The exploration of underwater cave systems pushes the limits of human endurance and requires a deep respect for the environment. Cave divers are drawn to this extreme activity because of their desire to discover hidden, untouched spaces below the surface—understanding the potential dangers involved and prioritizing safety above all else.
When speaking to experts, they say to make mistakes and learn from them. All the training you have to go through to become a cave diver is entirely essential—but without getting out there and experiencing the caves themselves, it doesn’t mean all that much. There are also the five golden rules of cave diving that must be followed at all times, no matter what. They are absolutely never to be broken.
Going Below the Surface
So, what exactly was I doing in this remote town of Mt. Gambier, as a newly appointed Divemaster, after six months of non-stop training? Simply put, I got the bug I mentioned before. For me, furthering my diving experience meant continuing down a path of curiosity and wonder. I wanted to know what else was out there and how I could push myself further.
The goal of my visit was to see what the underground world of diving was all about—and to meet some of the pros to hear from them directly.
The only place that you can dive recreationally and without certification in this area is the legendary Kilsby Sinkhole and, equally wonderful, Ewens Ponds. Both freshwater locations sit at 15 °C all year round and are some of the most pristine dives I have ever experienced.
Donning a 100 meter underwater heating vest under my 7mm and 3mm wetsuit combo (as there wasn't enough space in my expedition pack for the dry suit), I plunged into the 65-meter Kilsby Sinkhole for a once-in-a-lifetime guided dive.
I also met Josh Richards—a diving legend in these parts. Josh is a linchpin character when it comes to Mt. Gambier’s dive community, having brought many new cave divers into the fold. Having run a community-driven hostel called “The Habitat” for many years, he was the source of truth for next generation cave divers in South Australia.
Going Deep with Josh Richards
In our conversations, he told me about an elite group of cave divers called "The Soggy Wombats." Formed by Josh, each are his go-to divers when he’s ready to search for a new system or tackle some of the most challenging sites. He and his team were able to publicly announce the discovery of a new system, the Englebrecht's East Cave Extension (aka EEX), and are constantly in pursuit of more discovery in the Mt. Gambier region.
“EEX was certainly the most challenging in terms of exploration, conservation and safety. Exploring a new cave is significantly more hazardous than standard cave diving, as you're often entering areas that no human has ever been.
More people have walked on the moon than have been to the end of the Southern branch of EEX. The risk of the ceiling collapsing or losing the line in a silt-out is orders of magnitude higher,” Josh said.
EEX was a particularly complex cave for Josh because the entrance is easily accessible and right in the middle of town. And while it's some of the most challenging diving Josh has ever done personally, the site was originally rated for mid-level cave divers.
The new section he discovered is now rated for advanced sidemount cave divers only. Prior to their announcement, they had been particularly careful that no one with insufficient training would access the cave and attempt to follow their footprints in exploration.
At the SSI Extended Range Cavern Diving level, there are currently 6 diveable sites in Mt. Gambier, with 2-3 interstate. At the SSI Cave Diving level, there are another 7 diveable sites in Mt. Gambier, plus another 4-6 interstate (including parts of the Nullabor). Finally, at the SSI Full Cave Diving level there are another 3 sites, including Iddlebiddy, Tank and Stinging Nettle caves, as well as access to the advanced sections of 2 SSI Cave Diving level sites (EEX and Pines).
In my week in the freshwater capital of Australia, this group of exceptional divers taught me to engage and follow my curiosity, as there are amazing dive sites all around us.
There really is so much to uncover if you’re willing to put in the effort and look past where others stopped. When qualified, there’s a whole underground world to explore that will challenge you beyond comprehension. The question is, are you ready to take the plunge?
START THE ADVENTURE – BECOME AN SSI EXTENDED RANGE CAVERN DIVER.
Andi Cross is an SSI Ambassador and lead of the Edges of Earth expedition, highlighting stories of remote ocean conservation communities and organizations in 50 destinations worldwide.
To keep up with the expedition and see where the team is going next, follow the team on Instagram, LinkedIn, TikTok, YouTube and their website.