Volcanic Rock and Bubbling Lakebed
Snorkelers consistently describe Kleifarvatn’s underwater scenery as a bubbling geothermal field: hot springs at the bottom send up continuous curtains of bubbles, and the surrounding rocks can even vibrate slightly from the pressure of the escaping gas.
Kleifarvatn lies in one of Iceland’s most geothermally active regions, right on the Mid-Atlantic Ridge where tectonic plates are pulling apart.
Several features make this lake unusual:
- It has no visible inflow or outflow rivers — its water comes and goes through underground springs and porous lava
- Underwater hot springs have been found only a short swim from shore, where warm water and gases escape through vents in the lakebed.
- In one area, hot water from surface springs enters the southern part of the lake, while the rest of the lake is very cold.
Water temperature: 2-6C
The lake is cold, even though geothermal water is present. Near the hot springs you may encounter slightly warmer patches or notice a change in how the water feels, but overall you should treat Kleifarvatn as a cold-water snorkel, not a hot pool.
Best Time to Snorkel
Tour companies describe snorkeling at Kleifarvatn, as possible year-round, since temperatures are relatively stable across seasons. Some operators may limit or adjust tours in winter due to weather and access, even if the lake itself doesn’t freeze uniformly
Guided Tours
Several Icelandic operators offer geothermal snorkeling tours at Kleifarvatn,
Who is it for?
Tour operators clearly state that you don’t need to be an experienced snorkeler as long as you can swim and are comfortable in the water.