The Lava Tunnel in South Iceland

The Lava Tunnel in winter

The Lava Tunnel offers a truly unforgettable underground adventure for travellers in Iceland. Read further to learn more about this exciting, family-friendly attraction in Iceland’s scenic southwest. 

For the last year, I worked as a tour guide at Raufarhólshellir, better known to most as the Lava Tunnel. 

Now having left, its fitting to have this final opportunity to share what a fascinating geological site it is. So, allow me to lay out the many reasons why you should make time to visit this intriguing cave system during your trip. 

Helmets at the ready!

Table of Contents

At 1360 m (4500 ft) long, Raufarhólshellir not only happens to be one of the most beautiful lava tunnels in Iceland. It’s also one the easiest to get to. 

Relatively closeby to the urban delights of Reykjavík, this unique attraction is an increasingly popular choice among travellers looking for a quick tour near to their accommodation. But it is not merely ease of access that draws the crowds. 

The Lava Tunnel itself is a breathtaking sight to behold, and stopping in to discover it is an experience you won’t forget in a hurry. 

Within its craggy walls, guests will  uncover a mesmerising realm sculpted by the volcanic forces. It is spectacular in scope. Alive with various colours and textures. Almost all who explore this twisting basaltic ruin are blown away by the sheer majesty on display.

The Lava Tunnel entrance
Photo: Michael Chapman. Outside of the Lava Tunnel on a misty morning.

The History of the Lava Tunnel 

 

In Iceland’s past, bandits and outlaws would utilise local cave systems as a form of shelter, both from the unforgiving elements and the vigilant hand of justice. 

While there is no proof that Raufarhólshellir was used as a shelter by this island’s more unsavoury characters, it is quite possible given how close the cave is to Reykjavík.

The first time the cave’s whereabouts were recorded in writing was in 1909.

Early cavers in Raufarhólshellir.

How did the Lava Tunnel form? 

 

While you’re sure to learn exactly how lava tunnels such as Raufarhólshellir form during your visit, it is always handy to have a little knowledge beforehand. 

Raufarhólshellir would have been formed in what’s called an effusive eruption. It originated from a volcano called Leitin, which is part of Bláfjöll, or Blue Mountains

Effusive simply means that lava poured directly from the ground into the open, rather than erupting beneath a glacier, such was the case with Eyjafjallajökull in 2010. 

As this lava travels across the landscape, it will sometimes find itself following predetermined routes, normally by flowing into canyons, crevasses, or any dip in the terrain it can find. With this in mind, it is easy to imagine the rivers these lava flows would have made.

A map of Raufarhólshellir.

Volcanism in action!

All of this is very well, but how does the tunnel hollow out? What is to stop the lava from simply hardening where it is? 

Well, each lava flow has a surface on the top, just like physical liquid. As it moves forward, this top layer cools down and hardens quicker than everything beneath it. 

This allows new lava to flow over the top of what came before, adding another layer of basalt. It also keeps everything beneath hot and insulated. 

Given that the lava is moving at speed, and sits at a depth that is warmer than what’s above, the lava continues to flow without issues. This process repeats itself as long as the lava continues to push from the ground. 

In Leitin’s case, carbon dating indicates the eruption for almost five years continuously, hence the size of the tunnel today. 

Photo: Michael Chapman. Visitors entering the cave

What happened once the eruption ended? 

 

When Leitin finished erupting, lava drained out of the cave, leaving a wide open space beneath the surface. Experts estimate the lava only took five months to drain. This length of time was determined by counting the various flow lines – or stratas – that slice across the original lava wall. 

While this lava oozed outside, the cave itself would have entered what’s known as a cooling period. This means that the original lava wall – the first rock that cooled down upon the lava leaving – went from extremely hot to extremely cold. It did so very quickly. 

As a result of this temperature change, the original lava wall began to crumble and break apart, leaving the majority of the cave in a state of breakdown

In other words, the tunnel would have once been far narrower than what is seen today. But while guests walk on boulders once part of the ceiling, there are many examples of the original lava wall inside. 

No doubt, your guide will point it out along the way, but keep your eye out for any rock that appears smooth, grey, and resembles melted candle-wax.

Photo: Michael Chapman. Outside the main building.

Where is the Lava Tunnel?

 

The Lava Tunnel is located in the municipality of Ölfus. It is approximately forty minutes drive from Reykjavik, or 41.9 km (26 mi.)

The closest towns to the Lava Tunnel are Þorlákshöfn, Selfoss, and Hveragerði. Other than these locations, there are few attractions nearby. That is unless you happen to be exploring further along the South Coast. 

With that said, some people choose to drive, and then hike, to a nearby geothermal river called Reykjadalur after visiting Raufarhólshellir. The soothing warm waters of this natural spot offer a welcome relief after using your muscles to walk along the Lava Tunnel’s uneven pathways.  

What can you do at the Lava Tunnel?

 

It is only possible to visit Raufarhólshellir as part of a guided tour. These tours run on the hour, every hour. Sometimes extra slots can be added during the peak season in summer, and evening tours are also available. 

But, typically, the first group of the day leaves at 9AM, and the last at 5PM. A trip inside will generally take around 60 minutes. 

There are two tours available. The Standard Tour and the longer, more demanding Lava Falls Adventure Tour. 

Follow the links provided to find out more information about each tour.

Prices are as follows: 

Standard Tour 

(Adult): 8400 ISK

(Ages 12 – 15): 2500 ISK

(Under 11): Free

Lava Falls Adventure Tour (Adult): 25.900 ISK 

Lava Falls Adventure Tour (Ages 12 – 15): 12.950 ISK

Photo: Michael Chapman. One the three 'sky lights' at Raufarhólshellir

Which tour best suits you?


Please note that all tours are guided in English. However, laminated information packets can be provided in French, German, and Spanish, upon request. 

This means that even guests without strong English skills can still understand all of the relevant information during their time inside.

For a bigger price, private tour groups can also book a place, allowing you to have a tour guide all to yourself. However, private tours only limit the size of the group. It does not make any difference as to how many people are in the cave at any one time.

Regardless of which tour one chooses to take part in, know that it is best to book a spot online beforehand. By checking out the Lava Tunnel’s website, it is possible to see which tours are fully booked and which still have space available. 

Online booking is also the go-to method for travellers requiring a bus transfer to the site. Do note, however, that transport is handled separately by Reykjavik Excursions.

Photo: Michael Chapman. Inside the Lava Tunnel.

Are combo-tours with the Lava Tunnel available? 


Fantastic question – if I do say so myself!

Of course, it is possible to include the Lava Tunnel as part of a bigger package. Indeed, it is encouraged for those looking to maximise their days in the land of ice and fire

Some of the combo-tours available with the Lava Tunnel included are:

þingvellir national park
Photo: Páll Stefánsson. þingvellir during the winter.

What is included as part of the standard tour? 

 

Visitors arrive at a small rectangular building, seemingly in the middle of the wilderness, with a gravel car park attached.

From the road, there is very little giveaway that a snaking lava tunnel exists only a few metres below. But, actually, the surrounding landscape is all a lava field, formed as part of the same eruption that created the lava tunnel itself. 

Before your tours begins 

 

Once inside, it is expected to check-in with the receptionist should you have booked online. If you are walking in for the first time, hoping to experience the Lava Tunnel on impulse, the reception also happens to be where tickets can be purchased. 

Before your tour starts, help to wile away the minutes by browsing the variety of products on display, from troll plush toys to volcanic candles, specially-made lava chocolate bars, and clothing items brandishing the Lava Tunnel logo. Of course, a variety of refreshments can also be purchased at the main desk, from soft drinks to coffees. 

Photo: Michael Chapman

What equipment do you need to visit the Lava Tunnel?


A
round five minutes before the beginning of your tour, your guide will explain the necessary equipment. 

This includes a headlamp-fitted helmet, optional hiking poles and, in winter, spiky crampons for better grip. 

Upon kitting you out, they will then provide an informative safety briefing. Listen closely as they explain what to expect on the tour, and also the rules. 

The majority of these regulations are common sense given the that Raufarhólshellir is a protected site. This means that: eating, drinking, smoking, vaping, chewing gum, or relieving oneself are all banned. Little surprise there. 

However, it is also important to respect the sanctity of the environment. Therefore, guests are asked to avoid drawing in the snow or breaking icicles.

The Lava Tunnel helmet
Photo: Michael Chapman. You will be provided a helmet before entering.

Entering the Lava Tunnel 

 

For the first half of the tour, a tour guide will lead you throughout the cave. Your route follows a makeshift path that switches between jutting rocks, metal walkways, and stairs. This variety of terrain means that older visitors – or those who find walking on uneven surfaces difficult – will want to bring along a hiking pole for extra support. 

The guide will stop the group three times to explain how the cave was formed, and point out the geological specimens on display. That includes various minerals, strange lava formations, and volcanic glass called Tachylite, formed as a result of molten lava cooling rapidly.

Photo: Michael Chapman. Volcanic glass inside Raufarhólshellir

While this might sound heavy on geology – and indeed, the tour is – there’s more than rocks you’ll find inside. 

The guide will likely point out the glittering, primitive forms of life that call the cave home. Plus, they might flick the lights off, demonstrating the tranquillity, and novelty, of total darkness

On top of that, winter visitors will have the chance to observe a standing army of intricate, naturally-forming ice stalagmites. These give the cave an otherworldly aesthetic. But it’s not all bad news for those exploring during the summer months. Without ice and snow covering the path, walking in and out is a much easier affair.

But, let’s not spoil too much of what’s in store. Raufarhólshellir is a cavern filled with secrets. It would be a shame to over divulge what lies in wait for those who opt to venture inside. 

Photo: Michael Chapman. The biggest sky light in the cave

Discover a unique venue space 

 

Guests also have the opportunity to check out what is colloquially called the party platform, which serves as the last stop inside at around 400 metres. 

This part of the tunnel is aptly named because it can be rented for performance events, including music concerts and cinema screenings.  

It should also come as little surprise that the party platform has seen a number of weddings, and even wedding proposals, occur there. However, not all have gone exactly to plan. 

(Make sure to ask your guide about these romantic failures. They’ll be happy to dish the dirt!) 


In the meantime, be sure to check out our gallery of black and white shots taken at Raufarhólshellir during the winter. The intention of these photographs was to showcase the variety of textures one can find in the cave. 

What is included as part of the Lava Falls Adventure tour? 

 

The Lava Falls Adventure tour offers far more of a challenge than the shorter standard tour, but arguably, the rewards for participating are greater. 

Inside the Lava Tunnel
Photo: The Lava Falls Adventure Tour

That is because guests will not only explore the entire length of Raufarhólshellir, but they will also witness some interesting ‘waterfall’ type formations. With one located at the end of each of the three breakaway tunnels, these formations serve as lasting reminders of the final lava that flowed inside. 

Unlike the standard tour, those participating in this longer excursion will need to read the fine print of their booking carefully. 

Not only will the attached paperwork lay out exactly what can be expected on the tour, but it also makes clear that you will need to arrive in a pair of hiking boots, complete with ankle-support. 

Allow me to reiterate; if you do not turn up to check-in wearing the correct footwear, you will be turned away. You have been warned.

Guests are also required to sign a medical waiver.  

The Lava Falls Adventure tours
Photo: Michael Chapman. Yours truly at the end of the Lava Tunnel.

Take part in an underground adventure 

 

The Lava Falls Adventure tour takes anywhere between 3 – 5 hours to complete, depending on the speed of the guests. Those who take part will traverse over hills of loose debris and rocks, taking extra care where they step, while also enjoying the thrilling sights inside.

Before heading in, however, understand that the guide is in charge throughout the duration of your excursion. If, for any reason, they decide that it is better to end the tour early, then their decision must be adhered to. 

Following your guide’s leadership is particularly important given the fact that there is no radio signal inside. Therefore, pushing people to their physical limit is considered dangerous. After all, the farther one ventures inside, the greater the distance they have to return. 

There is no use getting all the way to the end of the tunnel only to call it quits and start seeking other means of exiting. Instead, it is much better to remain honest with your guide and only take on what you feel comfortable doing. 

Photo: Michael Chapman

Life-Threatening Conditions in Eldvörp Caves, Warning Issued

Grindavík - Þorbjörn

Following gas measurements conducted yesterday, the Icelandic Met Office has issued a warning for caves near the Eldvörp crater row in the Reykjanes peninsula (west of the Blue Lagoon). The Met Office conducts such analyses every week after a series of earthquakes, which resulted in considerable land uplift near Mt. Þorbjörn by Grindavík, occurred in late January.

A warning issued by a natural hazard expert with the Met Office states that changes in gas concentration have been measured, and in light of this the Met Office warns against exploring caves in the area. Measurements within one cave, in particular, indicated a life-threatening concentration of carbon dioxide along with a lack of oxygen.

“There are many caves in the area, but the cave in question is near a parking lot popular among travellers seeking to visit the Eldvörp crater row,” the statement reads. The Department of Civil Protection and Emergency Management has been apprised of the situation.

In an interview with RÚV, Kristín Jónsdóttir, team leader with the natural disaster watch at the Met Office, stressed that the Met Office’s warning only applied to caves in the area: “Walking in the area should be safe. It’s a beautiful area and it’s fun to explore. But we’re warning travellers to refrain from exploring the caves.”

This article was updated at 2.33 pm.