Quick summary
- You can walk the floor of an empty magma chamber that last erupted about 4,500 years ago.[1]
- The approach is about 3 km each way and usually takes around 45 minutes, so the effort is reasonable.[2]
- A lift carries you 120 meters down into the vault, and you get roughly 35 to 45 minutes inside.[3][4]
- The guided day trip is rated 4.85 from 630 reviews and runs 4 to 6 hours.[5]
- Reserve now and pay later, with free cancellation up to 24 hours in advance.[5]
- Top choice Thrihnukagigur day trip from US$432 Duration4 - 6 hours[5]Guide languageEnglish, IcelandicCancellationFree up to 24 hours[5]Rating4.85 from 630 reviews[5] Check availability
- Lava Tunnel by bus from US$153 Duration3 hours[6]Guide languageEnglishCancellationFree up to 24 hours[6]Rating4.59 from 850 reviews[6] See this tour
- Volcano and Reykjanes hike from US$132 Duration9 hours[7]Guide languageEnglishCancellationFree up to 24 hours[7]Rating4.65 from 1,154 reviews[7] See this tour
The last eruption, which took place about 4,500 years ago, left behind a unique natural phenomena: Þríhnúkagígur "Three peak crater".
Verdict: worth it for the right traveller
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What makes Thrihnukagigur so unusual
Most volcanoes you visit in Iceland are admired from the outside. Thrihnukagigur, a dormant volcano in the Bláfjöll mountains, is different: you can go inside it. The last eruption, which took place about 4,500 years ago, left behind a hollow vault, and geologists believe a deep underground rift drained the molten rock to create the space you walk into today.[1][9]
The chamber itself is about 120 m deep, and the bottom floor measures 50 by 70 m, large enough to feel like a buried cathedral.[1] Its walls are streaked with reds, yellows and greens, colours that come from mineral deposits left by the eruption, and the palette shifts as your eyes adjust to the low light.[10] The crater was discovered in 1974 by cave explorer Árni B. Stefánsson and opened for tourism in 2012, so the experience is still a relatively new addition to Iceland's travel circuit.[11]
For most visitors the scale is the surprise. The cavity spans 3,270 square metres, a figure that is hard to grasp from photographs, and the emptiness is what stays with you.[9] You feel the height of the walls, the silence, and the sheer strangeness of standing where molten rock once rose. It is not a cave, not a mine, and not really a crater in the usual sense. It is simply a volcano you can walk around inside.
The hike to the crater is part of the charm
The day begins at a ski cabin in Bláfjöll, about a 30-minute drive from Reykjavik on paved road.[8] From the meeting point, the path to the crater is about 3 km each way, and it usually takes about 45 minutes to cover with your guide.[2] It is a steady walk across old lava, with moss, red scoria and wide mountain views to keep you company.
The walk is more than a way to reach the crater. Thrihnukagigur cannot be visited independently, and the guided tour hike is one of only two ways to reach the volcano base; the other is by helicopter.[2] A helicopter option exists for anyone who wants to skip the walk, but the hike is the path most travellers take, and it builds the sense of arrival before the descent.[12]
The path is short and steady, and it suits anyone with ordinary fitness. You do not need trekking poles or technical gear, just sturdy shoes, warm layers and a weatherproof jacket. The guide sets a pace that keeps the group together, and there is no rush. By the time you reach the crater rim, you have earned the view.
A line of walkers crosses the lava field towards the red scoria cone.
Descending into the volcano
At the crater rim you are fitted with a harness and helmet, then step onto a lift that lowers you into the mountain. The descent is 120 meters (400 feet), and the ride takes about 6 minutes.[3] As you drop through the narrow entrance, the chamber opens out around you and the floor appears far below.
Visitors typically spend about 35 to 45 minutes inside the volcano, counting the descent, the time on the chamber floor and the ride back up.[4] There is room to walk around the 50 by 70 m floor, and the mineral colours on the walls give the space a stained-glass feel.[1][10]
The air underground is cool, and a jacket is worth carrying, but the space itself is not a tight cave. The floor is firm and mostly even, and the guides keep the group together as you explore. Standing inside a dormant volcano feels less like a theme park and more like entering a natural cathedral, with echoes and shadows that change as you move.
Is Thrihnukagigur worth the price?
The guided hiking day trip costs from US$432, one of the bigger single-day expenses you might choose in Iceland.[5] The tour runs 4 to 6 hours, which turns the price into a full outing rather than a quick add-on.[5] You get transport, a live guide and the run of a very unusual place.
Traveller feedback suggests the experience delivers. The tour is rated 4.85 from 630 reviews, with live guiding in English and Icelandic.[5] By contrast, the Raufarhólshellir lava tunnel is 1360 m long and formed about 5200 years ago, and its tours cost considerably less, but it offers a different wonder: walking through a tube rather than standing inside a drained magma chamber.[13][14]
The decision comes down to what you want the memory to be. A cheaper lava tour gives you a look inside the ground; Thrihnukagigur gives you the chance to stand inside a volcano. For many travellers, the rarity of that moment is what justifies the cost, and the strong rating suggests they do not regret it.
from US$432
Descend 120 meters into a dormant volcano's empty magma chamber on a guided day trip rated 4.85 from 630 travellers.[3][5]
What the tour day looks like
Pickup is available from Reykjavik, and you do not need a car for this trip.[5] A bus or coach carries you from the pickup points to the Bláfjöll meeting point, and a live guide takes over for the hike and the descent.[5] The stops on the listing show the shape of the day: pickup, the mountain, the crater and the journey home.
The tour operates every year from May 5th to October 30th, and outside that window the crater is closed.[2] Within the season, starting times vary, and you should check availability for the date you have in mind.[5]
Booking is flexible. You can reserve now and pay later, and cancellation is free up to 24 hours in advance.[5] That leaves room to adjust your plans if a weather front moves in or your Iceland itinerary changes. Given the price, the flexible booking policy is a genuine comfort.
Who should book this tour
The minimum age limit for the Inside the Volcano tour is 8 years old, which makes it realistic for families with older children.[4] The hike is easy enough for kids who are used to walking, and the lift and the chamber floor are exciting without being extreme. Teenagers often rank it as the highlight of a Reykjavik trip.
It is a strong fit for travellers who love geology, unusual landscapes or simply being outdoors. It is less ideal on a tight schedule, when the full trip takes 4 to 6 hours, or if you would rather see Iceland from a coach window.[5]
If the price feels steep, you can pair it with cheaper lava experiences on other days. The Lava Show in Reykjavik is an immersive take on molten rock, and Raufarhólshellir lets you explore a lava tunnel formed about 5200 years ago.[13][15] Together they give you a well rounded picture of Iceland's volcanic side.
Planning your Thrihnukagigur visit
Book early, especially for a summer date. The operating window is limited to May 5th to October 30th, and the tour's rating of 4.85 from 630 reviews tells you it is popular.[2][5] A little planning goes a long way.
Dress for Icelandic weather. Sturdy walking shoes, warm layers and a waterproof outer shell will carry you through the hike, which is about 3 km each way over uneven lava terrain.[2] On bright days, sunglasses and a hat help, and a small backpack is handy for the layers you shed.
Give the trip most of a day. The tour lasts 4 to 6 hours, and you will appreciate a relaxed meal afterwards.[5] If you plan to drive, the meeting point at Bláfjöll is about a 30-minute drive from Reykjavik on paved road.[8] Arrive a little early, and the whole day runs more smoothly.
How travellers rate volcano and lava experiences
GetYourGuide ratings: 4.94[16], 4.88[17], 4.85[5], 4.78[18], 4.75[15], 4.70[14].
Compare Iceland lava tour prices
When to book your Thrihnukagigur day
How to book your trip
Check the season
The tour runs from May 5th to October 30th every year.[2]
Pick a date
Choose a date and select pickup from Reykjavik when you reserve.[5]
Reserve now, pay later
Secure your spot with reserve now and pay later.[5]
Keep it flexible
Plans changed? Cancel free up to 24 hours in advance.[5]
Meet at Bláfjöll
Head to the meeting point about 30 minutes from Reykjavik, or use pickup.[8]
Hike and descend
Hike to the crater, ride down 120 meters, explore the chamber floor.[2][3]
A rare chance to stand inside a volcano awaits
from US$432Reserve now & pay later
