[5] He began diving in the Hell Complex, part of the Green Holes group of underwater sea caves off Doolin, County Clare and initially used the area as a training ground for his newly acquired skills.
[2][11][3] Perhaps his most notable achievement was the exploration of over 10 km (6.2 mi) of underwater passage in the notoriously unforgiving cave passages of the Gort region, including the discovery and exploration of Pollindre, 1 km in length and the third deepest sump in Great Britain and Ireland[citation needed] at 82 m (269 ft).
[12] In March 2011 Kozłowski received the Kolosy award for cave exploration at the annual Polish travelling and outdoor sports conference, held in Gdynia.
[16] His body was successfully recovered on 10 September 2011 after an extensive recovery effort over several days by a team including Jim Warny, Jason Mallinson, Rick Stanton and John Volanthen.
[20] In 2013, a fundraising page was set up in order to pay for a headstone for Kozłowski 's grave in Kiltartan, and for a plaque to be erected at the entrance to Pollonora 10.