Vouliagmenis Lake

Vouliagmenis Lake (Lake Vouliagmeni) is a unique natural thermal lake on the Athens Riviera near the suburbs of southern Athens, fed by underground thermal springs that maintain water temperatures around 22-29°C year-round. This brackish lake sits in a collapsed limestone cave system, with underwater passages extending deep into the hillside — some still being explored by cave divers. The warm, mineral-rich waters create an unusual ecosystem. For recreational divers, the lake offers a fascinating and accessible dive in crystal-clear water with interesting cave openings visible along the lake walls. The beginner-friendly open water area contrasts with the serious technical cave system beneath, making Vouliagmenis a unique Greek diving destination just minutes from central Athens.