Lava Tunnel & Silfra Snorkeling Tour from Reykjavík

About 10 hoursGroup: Small groupModeratePick-up in ReykjavíkAge 12+All year

Visitors below the coloured walls of the lava tunnel

Walkway through the Raufarhólshellir lava tunnel

This lava tunnel and Silfra snorkelling tour combines two very different underground and underwater experiences in one day: exploring the Raufarhólshellir lava tunnel, then snorkelling the glacier-clear Silfra fissure at Þingvellir.

Raufarhólshellir lava tunnelÞingvellir National ParkSilfra fissure

Caving inside Raufarhólshellir, one of Iceland's longest lava tunnels
Snorkelling the Silfra fissure between the North American and Eurasian tectonic plates
Some of the clearest water in the world, with visibility over 100 metres
All snorkelling and caving gear provided, including a drysuit
A guide for the caving and a certified dive guide for the snorkelling

Your day, stop by stop

Click a stop for photos and practical tips.

1Pick-up in ReykjavíkPick-up from your accommodation in Reykjavík, starting at 8:00.

Red, purple and yellow lava on the tunnel wall

Raufarhólshellir lava tunnelA guided walk through a real lava tunnel with headlamps.

Walkway through the lava tunnel below an opening in the roof

Lit walkway and coloured walls in the lava tunnel

Raufarhólshellir formed about 5,200 years ago in the Leitahraun eruption, when lava kept flowing under its own cooled crust and then drained away, leaving a long hollow tube. At 1,360 metres it is the fourth-longest lava tube in Iceland, and one of the roomiest, up to 30 metres wide and about 10 metres high, so the standard tour involves no crawling or squeezing. It can only be visited with a guide.

Walking · uneven, rocky ground inside the tunnel

Read our Raufarhólshellir guide →

Path through the Almannagjá gorge at Þingvellir

Lunch breakA break between the two activities.

A break between the lava tunnel and Silfra. Lunch and snacks are not included, so bring your own.

Silfra fissure, ÞingvellirSnorkelling in a crack between two tectonic plates.

Silfra is a fissure in Þingvellir where the North American and Eurasian plates are slowly pulling apart. It is filled with glacial meltwater from Langjökull that has been filtered underground through lava for decades, so visibility often exceeds 100 metres, which makes it one of the clearest snorkel and dive sites in the world. The water stays at about 2 to 4°C all year.

Facilities · changing area at the Silfra car parkExtra · underwater photos taken by your guide

Read our Silfra guide →

5ReturnDrop-off back in Reykjavík.

About the lava tunnel and Silfra snorkeling tour

This tour puts two of Iceland's more unusual activities into one day. First is a walk through Raufarhólshellir, a lava tunnel formed by a flowing river of molten rock thousands of years ago, where your guide leads you through the tunnel with a headlamp, pointing out the different rock formations along the way.

After a lunch break, the second half is snorkelling the Silfra fissure in Þingvellir National Park, where the North American and Eurasian tectonic plates are slowly pulling apart. The water is glacial meltwater, filtered through lava rock for years before reaching the fissure, so it's extremely clear and very cold. You're fitted with a full drysuit and thermal layers, so you stay dry, but the cold water still comes as a surprise to most people.

Because of the drysuit and the swimming involved, this tour has real physical requirements: a minimum age of 12, height and weight limits, and the ability to swim without help. It isn't for anyone who is pregnant or has certain medical conditions, so check the requirements carefully before booking. It runs all year, since Silfra's water temperature barely changes with the seasons.

Make it your own

Optional extras, at extra cost

Hiking boot rental
Waterproof jacket and trousers rental
T-shirt to buy
Beanie to buy
Gloves to buy

Included

Pick-up and drop-off in Reykjavík
English-speaking caving guide and certified divemaster
All caving and snorkelling gear, including drysuit
Þingvellir National Park admission fee
Hot chocolate and cookies after snorkelling
Free underwater photos taken by your guide

Not included

Lunch and snacks (bring your own)
Towel and a change of clothes

What to bring

Warm base layers to wear under the drysuit
Wool or fleece socks and gloves
A change of clothes and a towel

Good to know

About 10 hours, including pick-up and drop-off in Reykjavík from 8:00
Minimum age 12; under 18s must be with an adult
Weight and height limits apply for the drysuit: roughly 45–120 kg and 150–200 cm
You must be able to swim without assistance
Not suitable if pregnant, or without medical approval for certain conditions
Runs all year
You must be able to understand and speak English

Questions people ask

How cold is the water?

Very cold, close to freezing, but you're in a full drysuit with thermal layers underneath, so only your face gets wet.

Do I need diving experience?

No, this is snorkelling, not diving, but you do need to be a confident, independent swimmer.

Is there a minimum age?

Yes, 12 years old, and anyone under 18 needs to be accompanied by an adult.

What if I don't fit the height or weight limits?

The drysuits only come in a certain range of sizes, so check the limits before booking, as they can't be waived.

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From34,990 ISKPer person