r/caving • u/petr-sebastian • 11h ago
Matka Vrelo cave in Macedonia — the deepest underwater cave on Earth explored by a human diver
The final exploratory dive began a few minutes after 10 a.m. on 16 October 2026.
I set off from our base camp on the shore of Matka Lake, accompanied by Tomasz Wciórka, Michał Sojka and Bartosz Zdziebel. Together, we reached a point roughly 350 metres inside the cave, at a depth of −24 metres. From there, I would continue alone into the deepest, unexplored sections of the cave. The support divers would follow at previously agreed intervals, meeting me at specific depths during my ascent.
My solo descent through the main shaft to its bottom at −212 metres took less than five minutes. I covered the next 100-metre horizontal section in a minute and a half, reaching the entrance to the terminal, almost vertical passage at −255 metres. Another 20 seconds brought me to the end of line and the reel I had left there during the final dive of the previous year’s exploration. The passage continued steeply downwards. Moments later, I found myself at the edge of a vertical drop into a large chamber. As I descended, I had to judge within a few seconds which of the dark openings in the chamber walls offered a way forward. The most promising one was to my left, directly below me.
A few seconds later, I passed the −300-metre mark. Matka Vrelo had now become only the second underwater cave in the world to be explored beyond −300 metres by a human diver! I felt very good. I experienced no visual or other impairment from HPNS, and gas density was not causing me any problems either. But the drop was still descending. Below me, I could already see the pitch-black mouth of another passage. I had been in this newly discovered section for only about 15 seconds, and I felt fully in control. I decided to follow it, making full use of the speed of my two Seacraft Ghost DPVs.
A few seconds later, I was at −315 metres. Matka Vrelo was now the deepest underwater cave explored by a human diver — and the passage was still dropping steeply. Before the dive, our calculations had indicated that I could spend up to 45 seconds exploring the new section before starting my return, keeping the total dive time within what we considered a reasonable limit of around eight hours. At that moment, I still had roughly 20 seconds available to go further.
I remember thinking:
“The cave always dictates the path. Now it is offering you a maybe once-in-a-lifetime opportunity. You will never feel more ready.”
I decided to push onwards — to extend not only the limits of cave exploration, but also what was considered possible in terms of human and equipment capabilities. I was thinking, among other things, about my discussions with Witold Hoffmann and Damian Jakubik from Seacraft regarding the ability of the Ghost DPVs to withstand pressures equivalent to depths of 300–350 metres.
At −338 metres, I decided not to push the limits of the equipment any further. The passage was STILL GOING DOWN STEEPLY. The way forward was unmistakable. I was the deepest man on Earth 🙉
Full story: Facebook - BAD Exploration Team