Grjótagjá is a small lava cave near Lake Mývatn in North Iceland, famous for its geothermal hot spring hidden inside. The cave was formed by volcanic activity during eruptions of the nearby Krafla volcano.
Molten lava carved the cave, and over time, warm geothermal waters filled its interior, creating a unique environment of clear, blue thermal water surrounded by rugged lava walls.
Historically, the cave was used for bathing, notably by the outlaw Jón Markússon in the early 18th century. The site became a popular natural hot spring destination until the late 1970s when volcanic eruptions caused the water temperature to rise dangerously high (above 50°C or 122°F), making bathing unsafe. Since then, the water temperature has varied due to volcanic activity, and bathing is currently prohibited for safety reasons.
Grjótagjá gained international fame as a filming location for Game of Thrones (Season 3, Episode 5), where it was featured as the secret cave where Jon Snow and Ygritte shared an intimate moment. Its dramatic beauty and mystique have since drawn many visitors to the site.
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Scenic beauty
The cave’s luminous, warm blue waters contrast strikingly with the dark lava walls, producing a captivating and almost magical atmosphere. Natural light filters softly into the cave, enhancing its mysterious charm and making it a favorite spot for photography.
Accessibility
Grjótagjá is located near Dimmuborgir lava fields and can be reached via Route 1 and then Route 860. Visitors must walk a short but rocky path to reach the cave entrance. Caution is advised on uneven terrain and steep steps. The site is on private land, and visitors are asked to respect the owners' rules and not bathe in the cave.
Cost
Visiting Grjótagjá is free, but there are no facilities on site.
Crowd level
As a popular filming location and natural attraction in the Lake Mývatn region, Grjótagjá can attract a steady stream of visitors, especially during summer. Early visits or off-season trips provide a quieter experience.