Grænavatn Green Lake

Grænavatn

Reykjanes

The vivid emerald color of Grænavatn stops most people in their tracks — it reads almost artificially green, the result of heat-loving algae and dissolved minerals in a lake that sits inside a maar-type explosion crater formed when rising magma hit groundwater over 6,000 years ago. The lake reaches around 46 meters deep, and the color shifts from bright lime near the shallower edges to a richer hue toward the center. A second smaller lake sits just to the north in a neighboring maar crater. The pull-off is right along road 428, a short drive from the Seltún geothermal area. A walking trail loops the crater rim in roughly 20 minutes; views are best from the eastern side. The site is free and accessible year-round. Plan to combine Grænavatn with Seltún on the same stop, since the steaming vents and boiling mud pools are only a few hundred meters away. The whole Krýsuvík area is about 40 minutes from Reykjavík via Route 42 on paved road. Color intensity varies considerably with cloud cover, so bright-green photos you see online often reflect ideal direct sunlight.

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