Reykjavík: Silfra Fissure Snorkeling and Lava Caving Tour

Silfra snorkeling is the star here: you float through crystal-clear glacial water between two tectonic plates, then spend part of the day underground in Raufarhólshellir Lava Tunnel. It is a rare pairing of Iceland’s geology above and below ground, with guides such as Weronika, John, and Jónas bringing plenty of calm instruction and good humor.

I like the free underwater photos, which save you from worrying about a camera, and the hot cocoa and biscuits waiting after the cold-water portion. The main consideration is the long, carefully timed day: you start around 9:30, reach Silfra for a sharp 14:00 start, and may spend several hours moving between sites.

Key points at a glance

• Walk inside Raufarhólshellir: See lava formations, colored rock, and total darkness in one of Iceland’s major lava tunnels.
• Float through Silfra: Snorkel in exceptionally clear water between the North American and Eurasian tectonic plates.
• Expect cold, not a casual swim: The dry suit helps you float and retain warmth, but your face and hands still meet glacial water.
• Guides do the hard work: A caving guide leads the tunnel walk, while a PADI-certified snorkeling guide handles the water portion.
• The day includes useful extras: Gear, Thingvellir admission, underwater photos, and hot cocoa with biscuits are included.
• Plan around the timetable: Lava caving begins at 9:30, and snorkeling begins at 14:00 sharp in Thingvellir National Park.

Two sides of Iceland’s geology in one day

This tour works because the two activities feel genuinely different. In the morning, you walk through rock formed by past volcanic activity. In the afternoon, you float through a water-filled fissure created by the slow movement of the North American and Eurasian plates.

That contrast gives the day more purpose than a simple collection of adventure stops. You first see what Iceland’s volcanoes left behind, then enter a place shaped by the forces still working beneath the island.

At $202 per person, this is not a cheap add-on. But the price covers two major activities, specialized caving and snorkeling equipment, two types of professional guides, admission to Thingvellir National Park, free underwater photographs, and refreshments after snorkeling. If you already plan to visit both Raufarhólshellir and Silfra, combining them can be good value.

The drawback is that you are committing most of a day. The schedule can also involve a return toward Reykjavík or a bakery stop between activities before continuing to Thingvellir. That break is useful for food, but it means the tour is not a tight, nonstop route.

Raufarhólshellir at 9:30: a volcanic tunnel with real darkness

Your first meeting point is Raufarhólshellir Lava Tunnel. You should arrive 15 minutes before the scheduled 9:30 departure. The tunnel is the result of earlier volcanic activity, and your guide explains how molten rock moved, cooled, and left an empty passage behind.

Inside, the appeal is not polished cave decoration. This is a lava tube, so expect rough volcanic surfaces, unusual natural patterns, and formations shaped by cooling rock rather than dripping limestone. One part of the route may reveal a rainbow of colors in the rock, while another gives you a chance to experience genuine darkness when the guide turns off the lights.

I like this section because it gives you something to look at closely. The tunnel is not just a dark corridor for photographs. Its walls show how flowing lava can leave behind ridges, layers, and odd shapes. If geology interests you, this may be the more quietly rewarding part of the day.

The walk is guided, and the pace allows time to hear about the tunnel’s formation and stop for photographs. Some arrangements let you explore part of the route back at your own pace after the guide has led the group through. Ask your guide what freedom you have before separating from the group.

Bring warm clothing and wear practical footwear suitable for a rocky underground setting. The tour supplies caving gear, but it does not replace sensible clothing. If you dislike enclosed spaces, claustrophobia is specifically listed as a reason this tour may not suit you.

The midday break: a practical pause, not wasted time

After the lava tunnel, you need time to eat and change your focus before Silfra. The exact flow depends on the day’s transport arrangements, but the group may stop at a bakery for food before the second activity. Some people have about 30 minutes there, so do not count on a long restaurant meal.

This break matters because snorkeling preparation takes time and the water portion is physically more demanding than it looks. Bring money or food plans for your own meal, since hot cocoa and biscuits are provided after snorkeling, not as a full lunch.

The day may also include a transfer back toward Reykjavík to collect or meet other participants before heading to Thingvellir. That can feel inefficient if you expected a direct route, but it is part of how a combined tour handles two different activities and groups. I would choose this tour for the two experiences, not for the shortest possible driving route.

The drive toward Thingvellir gives you views of Icelandic scenery and a useful change of pace. Still, check road conditions and weather before leaving Reykjavík. Allow enough time to reach the second meeting point, especially in poor weather.

Silfra at 14:00: clear water between moving plates

The snorkeling portion begins at 14:00 sharp. Arrive at least 15 minutes early at Thingvellir Parking P5, then walk about 400 meters back along the road to the smaller car park used by the snorkeling vans. Look for Arctic Adventures vehicles.

Silfra is a fissure in Thingvellir National Park, a UNESCO World Heritage Site. Here, the water fills a crack associated with the North American and Eurasian tectonic plates. The attraction is both visual and geological: you are not simply swimming in a cold pool, but moving through a narrow space linked to the slow separation of two plates.

The water is famous for its clarity and shades of blue. Underwater photos can show the rock edges and the clean, open view around you, so the included photography is a valuable part of the package. You do not need to handle a camera while wearing gloves and managing a dry suit.

The guide leads you along a gentle current. The route is not presented as a race, and the guide stays with the group. Guides including John, Taz, Steven, Nebo, and Jónas have been praised for clear explanations, patience, and close attention to safety. Names and staff can change, of course, but the important point is that the water section is run by PADI-certified snorkeling guides.

What the dry suit really means in icy water

The water is around glacial temperature, so you should not expect a warm swimming outing. The dry suit is designed to keep water out and provides strong buoyancy. Several people find that the suit helps them float with little effort, but your face and hands can still feel the cold.

You will be helped through the clothing process, which includes several layers and pieces of snorkeling gear. Getting ready can take longer than expected, particularly in cold or wet weather. Wear a T-shirt and leggings beneath the suit, then bring a complete change of clothes and a towel for afterward.

The clothing area may be outdoors, although extra vehicles can be available for changing. If the weather is windy or rainy, getting dressed is part of the challenge. Pack your spare clothes where you can reach them easily, not buried at the bottom of a suitcase.

The official requirements matter. You must be able to swim and feel comfortable in the water. The tour is not suitable for non-swimmers, people under 150 centimeters or 45 kilograms, children under 12, pregnant women, or people with listed conditions including heart, respiratory, blood pressure, epilepsy, diabetes, or other pre-existing medical issues. Medical approval is required if you have a medical condition.

Do not treat the dry suit as permission to ignore those rules. It helps with flotation and warmth, but the guide still needs you to move and respond in the water. Read the snorkeling handbook before booking, and contact the operator if your health or fitness situation is unclear.

The guide support is a major part of the value

Silfra can look simple in photographs: put on a suit and float. In practice, the suit can feel bulky, the mask needs adjusting, and the cold may make your first moments tense. A patient guide makes a big difference.

The strongest part of the instruction is the steady support. Guides check that each person is ready, explain how to position the body, and keep the group moving together. A participant who became tired halfway through was pulled along by the guide, while another person who decided snorkeling was not suitable could return and wait safely for the group.

That does not mean the activity is effortless. You still need to be prepared for cold water, limited freedom of movement, and the need to follow directions. If you are a nervous but competent swimmer, tell the guide early. If you are not comfortable swimming, choose another Thingvellir activity instead.

Group size can vary. Some outings split the snorkeling group into smaller groups of around four to six people, which gives the guide more room to help each person and makes the water route feel less crowded.

Photos, cocoa, and the small comforts afterward

Your guide takes underwater photos during the snorkeling route, and they are included in the price. This is especially helpful because bringing and using your own camera can distract from the experience, and ordinary phones are not suitable for these conditions.

Afterward, hot cocoa and biscuits help you warm up. It is a simple touch, but you will appreciate it after removing cold gear and changing into dry clothes. Bring your own towel and a full change of clothing. Warm layers are essential, even if the forecast looks mild.

Sunglasses are not allowed on the activity. Keep them in your bag rather than trying to wear them during preparation or the water portion.

Timing, transport, and how to make the day easier

The listed duration is five to nine hours, depending on the departure option and transport schedule. That wide range is a reminder to keep the rest of your day free. Do not book a tightly timed evening activity immediately afterward.

Hotel pickup and drop-off are available only if you select that option, and pickup is limited to selected Reykjavík points. If you drive yourself, you are responsible for reaching both activity locations on time. The first is Raufarhólshellir; the second is the Silfra meeting area at Thingvellir.

For a smoother day, I would:

• Arrive at the lava tunnel 15 minutes before 9:30.
• Bring warm clothes, a towel, and a complete change of clothes.
• Wear a T-shirt and leggings under the dry suit.
• Plan food for the break between activities.
• Check weather and road conditions before setting out.
• Reach the Silfra car park at least 15 minutes before 14:00.
• Keep the afternoon and evening flexible.

Free cancellation up to 24 hours before the tour and the reserve-now, pay-later option make planning easier, especially when Iceland’s weather can change quickly. They do not remove the need to arrive on time or meet the health and swimming requirements.

Who should book this combination

I would recommend this tour to you if you want active sightseeing and have a strong interest in how Iceland was made. It suits competent swimmers who are willing to tolerate cold water, wear a bulky dry suit, and spend much of the day on the move.

It is also a good choice if you have limited time in Reykjavík but want both a volcanic tunnel and Silfra without arranging separate bookings. The included equipment and photos simplify the planning, while the guides provide structure at two activities that would otherwise require specialist preparation.

You may prefer separate tours if you want a slower day, more control over meals, or a direct route without a midday transfer. The lava tunnel is interesting on its own, but Silfra is likely to be the highlight if you are choosing between the two. One participant described the cave as cool but called the snorkeling the part that felt out of this world, and that is a fair way to set your expectations.

Families should note the minimum age of 12. The activity is not suitable for pregnant women, people with mobility impairments or claustrophobia, non-swimmers, or anyone with the medical conditions listed by the operator. People below the minimum height or weight cannot participate.

Should you book the Silfra and lava tunnel tour?

Book it if you want a full Iceland adventure rather than a relaxed sightseeing day. The combination is unusual, the guides receive strong praise for friendly and careful instruction, and the included photos, equipment, park admission, cocoa, and biscuits make the $202 price easier to justify.

Skip it if cold water, enclosed spaces, or a long transfer schedule would spoil your day. For everyone else who can swim and meet the health requirements, this is one of the more memorable ways to connect Iceland’s volcanic past with its still-moving geology.

FAQ

Where does the tour begin?

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

When does Silfra snorkeling begin?

Snorkeling begins at 14:00 sharp. Arrive at least 15 minutes early at the Silfra parking area.

Where do I meet the snorkeling guide?

Park at Thingvellir Parking P5, then walk about 400 meters back along the road to the smaller car park with the snorkeling and diving vans. Look for Arctic Adventures.

Is hotel pickup available?

Hotel pickup and drop-off are available if you select that option. Pickup is offered from selected Reykjavík pickup points.

Is snorkeling gear included?

Yes. Snorkeling gear and caving gear are included, along with a PADI-certified snorkeling guide and a caving guide.

Can non-swimmers join?

No. You must be able to swim and feel comfortable in the water. The tour is not suitable for non-swimmers.

What should I bring?

Bring warm clothing, a towel, and a complete change of clothes. A T-shirt and leggings are useful under the dry suit. Sunglasses are not allowed.

Are underwater photos included?

Yes. Your guide takes underwater photos, and they are included at no additional cost.

Can pregnant women participate?

No. Pregnant women cannot participate because of the small risk of cold water entering the suit.