Diving
Explorer volcanic underwater hot springs and giant craters
Snorkeling
Snorkel directly over bubbling calderas
Fishing
Fishing enthusiasts can cast their lines for Arctic char and brown trout.
Hiking
Easy lakeside walks as well as challenging multi-hour hikes.
Activities
Scuba Diving in Underwater Geothermal Hot Springs
One of the most unique experiences at Kleifarvatn is scuba diving among underwater geothermal vents. Certified diving operators lead tours into areas where warm currents rise through the lakebed, creating surreal underwater landscapes.
What to expect?
Volcanic fissures, Bubbling hot springs, and abundant marine life.
Water conditions
Visibility: 2 to 15 meters (6.5 to 50 feet). Water temp: +2-6 C (35-43 F).
Considerations
Licensed tour operator required.
Lake Kleifarvatn is ideal for travelers seeking silence, raw landscapes, and geothermal features far from busy areas. Its atmosphere feels different from the more crowded Golden Circle stops. Therefore, it works well either as a short scenic detour or as part of a full day exploring the Reykjanes Peninsula.
Snorkeling and diving add an unusual perspective on the lake’s geology, while hiking and photography provide easy ways to enjoy the surroundings. As a result, the location appeals to both casual visitors and outdoor enthusiasts who value peaceful nature.
Kleifarvatn remains one of the peninsula’s most distinctive destinations. With careful planning and respect for local conditions, the lake offers a memorable and calm experience throughout the year.
The Beast of Kleifarvatn
Icelandic Folklore
Long before the roads reached the Reykjanes Peninsula, travelers told of a serpent that moved beneath Lake Kleifarvatn like a shadow with purpose. They said it rose only when the land itself shifted, sensing tremors long before humans felt them.
On mist-heavy mornings, shepherds claimed they saw a long, ridged back ripple across the still water, as if the creature were tasting the air before sinking again into the volcanic depths. No one ever heard it breathe, and no one ever found its trail.
Yet those who paused at the shoreline swore the lake changed when it was near—its surface tightening, its silence deepening—as if the ancient serpent was not merely hiding, but watching, waiting, and remembering the world before the first stories were told.
About Lake Kleifarvatn
Kleifarvatn is the largest lake on the Reykjanes Peninsula and one of the deepest in Iceland with max depth of 97 meters (318 ft.).
Kleifarvatn is known for its shifting water levels, an unusual trait for a lake with no surface outflow or connecting rivers. Its fluctuations are driven almost entirely by changes in the groundwater system beneath the Reykjanes Peninsula.
A dramatic example occurred in 2000, when a series of earthquakes opened a fissure on the lakebed, causing large volumes of water to drain into the surrounding volcanic substrate. The lake gradually refilled in the years that followed, but its level remains sensitive to underground movement and seasonal groundwater variation. Because of this ongoing instability, water levels are monitored regularly to determine safe access conditions for divers and researchers.
The surrounding area is quiet and has few buildings. This helps preserve the dark, almost lunar feel of the lava formations. The lake’s still surface often reflects the surrounding hills, which creates dramatic views during sunrise and sunset. Wildlife here is limited, but small birds and occasional Arctic char can be seen near the shoreline. Because the water is cold year-round (2-6 C), swimming is not recommended without proper thermal gear. Hot springs exist, creating warmer pockets (up to 9-10°C), but the overall lake water remains cold.
The roads around the lake are generally accessible for standard vehicles in summer. However, they may become icy or difficult in winter. Travelers should check local road conditions before visiting, especially early in the morning or after heavy snowfall. Parking areas are small and unpaved, but they are close to the most popular viewpoints.