Grjótagjá Cave

Grjótagjá

North

A narrow crack in a lava ridge north of Lake Mývatn opens into Grjótagjá, a small cave containing one of the most striking geothermal pools in Iceland — electric blue water glowing in near-darkness, framed by rough volcanic rock. The cave formed along a fissure in the rift system pulling the North American and Eurasian plates apart. For generations, locals bathed here, but Krafla eruptions between 1975 and 1984 drove the water above 50°C. It has cooled somewhat since, but bathing remains prohibited. The cave sits on private land — respect any posted signs. You can still walk inside and descend to the water's edge. The entrance is a small opening in the lava ridge near a parking area off Route 848, about 3 km east of Reykjahlíð. Hverfjall crater is close by, and most visitors combine the two stops. Grjótagjá appeared in Season 3 of Game of Thrones, though the scene was recreated in a studio; the actual cave is smaller and more intimate than it looked on screen. Budget about 20 to 30 minutes. Free to enter year-round.

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