Reykjavík: Silfra Fissure Snorkeling and Lava Caving Tour

Silfra’s cold, clear water gives you an unusual view of Iceland from below the surface: you float through a fissure between the North American and Eurasian tectonic plates. The day pairs that with a walk through Raufarhólshellir, a lava tunnel formed by volcanic activity.

I like the contrast between the dark, textured lava tube and Silfra’s blue water, and the practical touches matter too: guides help you into the gear, take underwater photos, and serve cocoa and biscuits after snorkeling. One thing to weigh carefully is the long, sometimes stop-and-start day, with separate meeting points and a cold-water activity that is not right for everyone.

The experience at a glance

• Walk through Raufarhólshellir: See volcanic formations inside a lava tunnel, with a caving guide to explain how the underground passage formed.
• Float through Silfra: Snorkel in exceptionally clear water at Thingvellir National Park, between two tectonic plates.
• Plan for two locations: The cave and snorkeling have separate meeting points, and Silfra snorkeling starts at 14:00.
• Expect cold conditions: Snorkeling gear is provided, but your face and hands may still feel cold.
• Get useful extras: The guide takes underwater photos, and hot cocoa and biscuits are served afterward.
• Check eligibility first: You must be comfortable in the water and able to swim, and the activity has several health, age, height, and weight restrictions.

A lava tunnel before the water

The first stop is Raufarhólshellir Lava Tunnel, where the morning begins with a guided walk through a passage created by past volcanic activity. Inside, you can look closely at the rock formations and see how lava shaped the tunnel. It is a good place to slow down and pay attention to Iceland’s geology rather than simply driving past another dramatic stretch of scenery.

The caving guide explains the formations as you go. One guide, remembered for an energetic and funny manner, made the geology easy to follow while checking that the group was comfortable. That kind of attention is useful in a cave: the setting is unfamiliar, and a guide can help you notice details you might otherwise miss.

The tunnel is not a limestone cave, so do not expect pale, polished chambers. Its appeal is the evidence of volcanic activity and the colour and texture of the rock. One visitor particularly remembered seeing a natural rainbow effect, while others appreciated being allowed time to look around and take photographs. The exact formations and colours you notice will depend on the conditions and where you stand.

The cave section makes a strong start, but it is only one half of the day. If caves are your main interest, keep in mind that the experience is a guided visit rather than a lengthy underground expedition. The big contrast comes later, when the dark tunnel gives way to the clear water at Silfra.

The pause between cave and fissure

After the cave, you have a break before snorkeling. Some versions of the day include a stop at a bakery for food, a welcome chance to refuel and rest before the next activity. One account describes the break as about 30 minutes, so treat it as a practical pause rather than a leisurely lunch.

The transfers and meeting arrangements deserve attention. The cave activity begins at Raufarhólshellir, while snorkeling starts in Thingvellir National Park. Some participants have experienced a return toward Reykjavík to collect people for the second part, so the overall travel pattern can vary. The advertised duration is five to nine hours, which reflects the fact that the full day depends on the schedule and transport arrangements.

If you are arranging your own transport, allow time for the drive and check weather and road conditions before setting out. For Silfra, park at Thingvellir Parking P5, then walk about 400 metres along the road to the smaller car park used by the snorkeling and dive vans. Look for Arctic Adventures, and arrive at least 15 minutes before the 14:00 start. The activity ends back at its meeting point.

Hotel pickup and drop-off are available only if you choose that option, and pickup is offered from selected Reykjavík locations. Confirm what you have booked rather than assuming the transfer is included. The separate meeting points make this tour less straightforward than a single-site outing, but the two very different activities are the reason the combination is appealing.

What makes Silfra different

Silfra is a fissure in Thingvellir National Park, a UNESCO World Heritage Site. Here, you snorkel in clear water between the North American and Eurasian tectonic plates. The setting is striking not because of busy crowds or a complicated route, but because the water lets you see the fissure’s shapes and blue tones beneath the surface.

A PADI-certified snorkeling guide leads the group through the activity. The current is described as gentle, and the equipment is supplied. The guides help you put it on and stay with the group, a reassuring setup if you are new to snorkeling or nervous about the cold.

The water is glacial and very cold. The dry suit helps keep your body warm and buoyant, but it does not make every part of you feel cosy. People who have done the tour describe cold, wet faces and hands, even when the rest of the suit kept them comfortable. Bring warm clothes for afterward, and be ready for the process of getting suited up in Icelandic weather.

The experience is a float more than a strenuous swim, but you still need to be comfortable in the water and able to swim. One participant who was unsure at first found the guide’s support helpful, while another person in the same group decided snorkeling was not for them and waited instead. That is a useful reminder: the guide can offer reassurance, but cannot make a cold-water activity suit every person.

Guides, safety and the underwater photos

The guides are a major part of what makes the day manageable. You have a caving guide at Raufarhólshellir and a certified snorkeling guide at Silfra, and the two sections require different kinds of help. In the cave, a good guide brings the volcanic story into focus. At Silfra, clear instructions and patient support matter as you handle unfamiliar gear and enter cold water.

Names that have come up from this experience include Weronika, John, Nebo, Steven, Taz and Jónas. The names are not a promise about who will lead your departure, of course, but the practical point is that guides help with the equipment and check on the group throughout the snorkeling. If you are uneasy, tell your guide before you enter the water.

Underwater photos are included and taken by your guide. That is a worthwhile extra, since handling a camera while wearing snorkeling equipment is not ideal. The photos also give you a way to remember the water and fissure without needing to bring your own camera.

Afterward, hot cocoa and biscuits offer a simple warm-up. Pack a towel and a change of clothes, along with warm layers for the journey back. You may also want a thin shirt and leggings to wear under the snorkeling suit, as some participants recommend. The required items are warm clothing, a change of clothes and a towel.

Is the $202 price worthwhile?

At $202 per person, this is a full-day combination, not a cheap add-on. The price covers caving and snorkeling gear, a caving guide, a certified PADI snorkeling guide, Thingvellir National Park admission, free underwater photos, and cocoa and biscuits after snorkeling. Hotel pickup and drop-off are included only if you select that option.

The value comes from combining two very different activities and having guides and equipment provided for both. You do not have to arrange a separate cave visit and Silfra session yourself, and the photos remove one small hassle from the water portion. For someone who wants both experiences, the package can make sense.

Still, price it against what you actually want to do. If cold water is a firm no, the cave alone may not justify booking this combined outing. If you are unsure about snorkeling, consider whether you would be satisfied waiting while the rest of your group goes in. The tour is best value when you are genuinely interested in both the underground geology and Silfra.

Who should book this combination?

I would put this tour high on the list for active visitors who want more than a scenic drive and are comfortable following instructions in unfamiliar settings. It suits people with an interest in geology, anyone curious about Iceland’s volcanic underground, and those keen to see Silfra from the water rather than from the shore.

It can also work for a first-time snorkeler who meets the requirements and feels at ease in the water. The provided gear and guide support help, but the activity is not suitable for non-swimmers. You should not book it if you are pregnant, under 12, under 150 centimetres or 45 kilograms, or if you have a listed condition that makes the activity unsuitable.

The supplied restrictions also include people with mobility impairments, claustrophobia, heart or respiratory problems, epilepsy, diabetes, high blood pressure, visual impairment, and pre-existing medical conditions. If you have a medical condition, medical approval from a doctor is required. Read the snorkeling handbook before booking and contact the operator if you are uncertain about your eligibility.

Before you reserve

Check the selected starting time and the pickup option carefully. The cave meeting point is Raufarhólshellir Lava Tunnel, with arrival requested 15 minutes before the scheduled 9:30 departure. Snorkeling begins at 14:00 sharp at Thingvellir, and you should be at the Silfra car park at least 15 minutes early.

Bring warm clothing, a towel and a full change of clothes. Sunglasses are not allowed for the activity. Check road and weather conditions if you are driving yourself, and leave enough time between locations. If your plans may change, the booking offers free cancellation up to 24 hours in advance and a reserve-now, pay-later option.

Should you book it?

Book this if you want a day with two genuinely different sides of Iceland: volcanic rock below ground, then clear, cold water at Silfra. The strongest reason to go is the snorkeling, with the lava tunnel adding context and variety rather than simply padding the schedule.

Skip it if you dislike cold water, feel uncomfortable in confined spaces, or do not meet the health and physical requirements. If you are eligible and excited by both activities, the included equipment, guides, photos and transfer options make the $202 price reasonable for a distinctive, carefully guided day.

FAQ

How much does the tour cost?

The listed price is $202 per person. Hotel pickup and drop-off are included only if you select that option.

How long does the tour take?

The stated duration is five to nine hours. Check availability for starting times, and allow enough time for travel between the cave and Thingvellir.

Where does the tour start?

The first activity begins at Raufarhólshellir Lava Tunnel. Arrive 15 minutes before the scheduled 9:30 departure.

Where does the snorkeling start?

Snorkeling takes place at Silfra in Thingvellir National Park and begins at 14:00. Arrive at least 15 minutes early at the Silfra car park.

What should I bring?

Bring warm clothing, a towel and a change of clothes. Sunglasses are not allowed.

Is snorkeling equipment provided?

Yes. Snorkeling gear is provided, along with caving gear for the lava tunnel.

Are underwater photos included?

Yes. Your guide takes underwater photos, and they are included.

Is food or a warm drink provided?

Hot cocoa and biscuits are served after snorkeling. A bakery stop may be part of the break between activities, but do not count on it as a full meal.

Can children join the tour?

The activity is not suitable for children under 12 years old.

Do I need to be able to swim?

Yes. You must be comfortable in the water and able to swim. The activity is not suitable for non-swimmers.