Sintzi Spring 2025 – The Final Push to -255 Metres
When I surfaced from Sintzi Spring in May 2024 after a dive to 240 metres, one thing was clear — the cave continued. The newly discovered passage did not end where I had turned around. I left my exploration reel at the end of the line, ready for another push.
A year later, we returned. The 2025 expedition was meant to conclude a three-year exploration project that had begun with our first dives in Sintzi in 2023. Over those three years, we gradually reached deeper and deeper sections of the cave — from the restriction at 94 metres and the former exploration limit at around 186 metres, through the discovery of a connection between the two deep shafts, and finally into completely unknown passages extending far beyond 200 metres.
This time, the objective was simple: return to the end of the line at 240 metres and find out where Sintzi went next.
Back to Sintzi
At the beginning of May 2025, our four-person team returned to the Peloponnese. The team consisted of:
Bartłomiej Pitala – main exploration diver
Tomasz Wciórka – support and equipment specialist
Mariusz Banaszak – support diver
Michał Sojka – support diver
Before the final dive could take place, several days of preparation were required. Sintzi is not a cave where you can simply arrive and head straight to the end of the line. The route to the deepest sections involves long underwater passages, restrictions and several deep shafts. Water temperature is around 10°C, and an exploration dive can last many hours. Bailout cylinders had to be staged along the route, equipment checked, guidelines inspected and the support plan carefully prepared. During the expedition, the team accumulated approximately 50 hours underwater. Everything led to one final dive.
May 1st 2025
On May 1, I set off towards the deepest known section of Sintzi. The route was already familiar from the previous two years, but knowing the cave did not make the journey simple. I still had to travel through the long entrance passages, pass the deep shafts and eventually reach the corridor discovered during the final dive of 2024. At the end of that route was the reel I had left there a year earlier. Beyond it was unknown cave.
I attached a fresh line and began exploring. The passage continued from the point where I had turned around at 240 metres the previous year. Once again, I was moving through a part of the cave that no human being had ever seen before. The depth gradually increased. The corridor continued. And the line kept running off the reel. Eventually, my computers showed:
255 metres.
During the dive, I explored and laid line through more than 100 metres of new passage, significantly extending the known cave beyond the point reached the year before. And once again, Sintzi did not end - at the deepest point of the dive, the passage was still continuing ahead. After three consecutive years of exploration, hundreds of metres of newly discovered cave and repeated dives into increasingly deep sections of the system, I had reached the limit planned for this project. It was time to turn around. I secured the guideline and left the reel at the end of the newly explored passage.
The way forward remained open.
The long way back to the surface
Reaching the end of the line was only the first part of the dive. The return through the deepest sections of Sintzi and the many hours of decompression still lay ahead. At this stage, the rest of the team played a crucial role, entering the cave according to the previously prepared schedule to meet me during the ascent. On a dive of this length and depth, support is not simply about waiting for the exploration diver to return - it involves transporting and staging equipment, placing and later recovering bailout cylinders, meeting the diver during decompression, being able to deliver additional gas or equipment if necessary, and being ready to respond if anything does not go according to plan.
The final dive lasted exactly 7 hours and 52 minutes. The other team members spent between approximately three and more than four hours underwater that day, supporting different stages of the ascent. When I finally surfaced, the entire team was there. Three years of work in Sintzi had reached its conclusion.
Three years of exploration
Our first expedition to Sintzi took place in 2023. At that time, one branch ended at a tight restriction at approximately 94 metres, while the deepest known part of the cave had previously been explored to around 186 metres.
In 2024, I managed to pass the restriction in sidemount configuration and began exploring the passage beyond it.
After laying more than 100 metres of new guideline, the passage unexpectedly connected with the main deep shaft. During the same expedition, I later reached the previous end of line in the deepest part of the cave and discovered a new passage. The final dive of 2024 took me to 240 metres, with the cave still continuing.
In 2025, we returned to finish what we had started. The final push extended the explored depth of Sintzi to 255 metres and added more than 100 metres of new passage. Sintzi remained the deepest explored underwater cave in Greece. And even after three years of work, we still had not reached its end.
The end of the project – but not the cave
For us, the 2025 expedition marked the end of this stage of Sintzi exploration. Over three years, the cave went from being a place we were only beginning to understand to becoming one of the most important exploration projects we had ever undertaken. We found a continuation beyond the restriction at 94 metres, connected the cave’s two deep shafts, pushed beyond the previous exploration limit at around 186 metres and ultimately reached a depth of 255 metres.
But the most interesting fact remains unchanged. At 255 metres, the cave still continues. The exploration reel remains at the end of the line, with more guideline still on it.
Sintzi is waiting for further exploration.
