Lava Tunnel Iceland: Þríhnúkagígur, Raufarhólshellir and Víðgelmir (2027)

You can go inside a volcano in Iceland. At Þríhnúkagígur, near Reykjavík, an open lift lowers you about 120 m into a magma chamber that emptied after an eruption around 4,500 years ago. The tour runs only from May to October. For the rest of the year, and for a shorter, cheaper trip, two lava tunnels are open on guided tours: Raufarhólshellir, about 30 km from Reykjavík, and Víðgelmir in the west. Here is how they compare.

Can you go inside a volcano in Iceland?

Yes. Þríhnúkagígur is a dormant volcano whose magma drained away instead of hardening, leaving a huge hollow chamber under a small crater opening of about 4 by 4 m. The chamber is said to be large enough to hold the Statue of Liberty.

The name means "Three Peaks Crater", after the three volcanic peaks in a row; Þríhnúkagígur is the youngest of them. The cave explorer Árni B. Stefánsson was the first person inside, in 1974, lowered on a rope through the opening by his friends.

How does the Þríhnúkagígur tour work?

The tour starts at a meeting point in the Bláfjöll hills, about 20 km south-east of the capital area. From there you hike about 3 km across a lava field to the crater, which takes 45–50 minutes each way and ends with a steep climb of about 50 m. At the top you put on a helmet and harness and step into an open cable lift, run by mountaineers, for the six- to seven-minute descent.

If you drive yourself, allow plenty of time to reach Bláfjöll; the road climbs into the hills and can be snowy early and late in the season. At the bottom you have about 30–40 minutes to walk around the chamber floor and look up at the walls of the chamber. Back at base camp, the tour serves Icelandic lamb soup, with a vegetarian option.

The 2026 season ends on 30 October, so the next chance is from May 2027. Book ahead in summer, and keep a spare day in case weather cancels your tour.

What is a lava tunnel?

A lava tunnel, or lava tube, is a cave left behind by a river of lava. As a lava flow moves, its surface cools and hardens into a roof, while molten lava keeps flowing underneath. When the eruption stops, the lava drains out and leaves a long, hollow tunnel. Iceland's young lava fields are full of them, and two of the largest are open on guided tours all year.

What is Raufarhólshellir like?

Raufarhólshellir is a lava tunnel 1,360 m long, up to 30 m wide and about 10 m high. It formed in a lava flow about 5,200 years ago and is often called the fourth-longest lava tube in Iceland. It is the easiest lava tunnel to visit from Reykjavík: about 30 km away, under 30 minutes' drive. Take Route 1 east for 18 km, then Route 39 for 12 km.

The standard tour takes about an hour and leaves every hour from morning to late afternoon, all year. You walk on built paths, a footbridge and some stairs, so there is no crawling, and children from 3 can join. Prices start from about ISK 8,900 per person (checked October 2026). Longer caving tours of about three hours are also offered. In winter, ice formations grow near the entrance. The tunnel is cold, damp and dark inside all year, so bring a warm layer even on a sunny summer day.

It is close to Hveragerði, so it pairs well with a walk to the Reykjadalur hot river or a day on the Golden Circle.

What is Víðgelmir like?

Víðgelmir is a lava cave about 1,585 m long at Fljótstunga, in the Borgarfjörður area of West Iceland, about two hours' drive from Reykjavík. It is often called the largest lava cave in Iceland by volume, with sections around 16 m wide and 15 m high, although longer lava tubes exist. It formed in a lava flow about 1,100 years ago, and remains dated to around the year 1100 found inside show people knew it in the Viking Age. Those finds are now in the National Museum in Reykjavík.

Tours run all year and take about 1.5 hours, from about ISK 9,000 per person (checked October 2026). Helmets and headlamps are included. Very young children may need to turn back before the final stop. The cave has been closed by a gate since 1993 to protect it, so the only way in is with a guide. If you are staying in Húsafell, shuttles to the cave run from Húsafell Bistro and are booked separately. It is a good stop on the way to or from Snæfellsnes or the Húsafell area.

Which should you choose: Þríhnúkagígur, Raufarhólshellir or Víðgelmir?

Choose Þríhnúkagígur if you want a once-in-a-lifetime experience and are visiting between May and October. Choose Raufarhólshellir for a short, easy trip from Reykjavík in any season. Choose Víðgelmir if you are heading west or north and want a bigger cave with fewer people.

What should you wear in a lava tunnel?

Dress for cold and damp, even in summer. Lava caves stay cool all year whatever the weather outside, and water drips from the ceiling.

• Warm layers: a fleece or wool jumper under a waterproof jacket.
• Sturdy shoes or boots with good grip; floors can be wet, uneven and icy in winter.
• Hat and gloves in the colder months.
• Hiking boots for Þríhnúkagígur, where the 3 km walk to the crater crosses rough lava.

Helmets and lights are provided on all three tours. Do not enter lava caves without a guide: many are unlit, have loose rock and are protected because their formations break easily.

Visiting near the Reykjanes Peninsula? Check vedur.is and safetravel.is before you go. These sites are outside the eruption zone, but roads in the area can close during volcanic activity.

For the lava fields of the recent eruptions, see our Reykjanes volcano guide. For every volcano on our map, read our guide to volcanoes in Iceland.

Facts checked October 2026. Tour prices, seasons and departure times are set by the operators and change every year; check their websites before you book. The Þríhnúkagígur season normally runs from May to October.