Reykjavík: Silfra Fissure Snorkeling and Lava Caving Tour

Walking through a lava tunnel in the morning and floating between tectonic plates in the afternoon makes this one of Iceland’s more unusual day tours. You begin at Raufarholshellir Lava Tunnel, where volcanic rock forms ribs, colors, and rough walls around the passage. Later, at Silfra in Thingvellir National Park, you snorkel through water so clear that every blue-green detail seems close enough to touch.

I like the strong geological theme: the cave shows what happens after lava cools, while Silfra shows the earth pulling apart below your fins. I also like the careful guiding, free underwater photos, and hot cocoa with biscuits afterward. The main drawback is the long, split schedule. You may need to travel between meeting points, wait between activities, and change outdoors in cold weather.

Key points before you book

• Two major stops: Walk through Raufarholshellir Lava Tunnel, then snorkel in Silfra Fissure.
• Clear, cold water: Silfra’s water stays near glacial temperature, but the supplied dry suit floats and insulates you.
• A full day out: The total duration is listed as 5 to 9 hours, with caving starting at 9:30 and snorkeling at 14:00 on the stated schedule.
• Guides matter here: A certified PADI snorkeling guide and a separate caving guide lead the activities.
• Photos are included: Your snorkeling guide takes underwater pictures at no extra charge.
• Not for everyone: You must swim, manage a dry suit, and meet the tour’s health, height, and weight requirements.

Raufarholshellir Lava Tunnel starts the day

The first stop is Raufarholshellir Lava Tunnel, in Iceland’s southern region. You meet at the lava tunnel 15 minutes before the scheduled 9:30 departure. Bring warm clothes and shoes suitable for uneven ground. Caving gear is supplied.

Inside, your guide explains how flowing lava once created the passage. As the outer layer cooled, molten rock continued moving beneath it, leaving a hollow tube behind. That process gives you something useful to look for: curved ceilings, hardened lava textures, and mineral colors that shift as the light changes.

This is not a polished limestone cave with grand stalactites. It is rougher and more volcanic, with dark rock and natural formations shaped by heat. Some sections show striking color, including the rainbow-like mineral effects mentioned by guides on past departures. The appeal is geological rather than theatrical.

The cave guide sets the pace and explains the formations along the route. Guides such as Norris, Yannis, and others have been praised for keeping the visit informative and lighthearted, while giving people time to take pictures. On some departures, you may walk back through part of the tunnel at your own pace after the guided section.

Expect real darkness at one point. That short moment helps you understand the cave better than a bright, fully lit passage would. It also means the experience may feel more physical and enclosed than a standard sightseeing stop.

If you have claustrophobia or limited mobility, take the warning seriously. This activity is not suitable for people with mobility impairments or claustrophobia. The cave is also not suitable for children under 12.

The gap between activities needs planning

After caving, you have time to eat before snorkeling. Some departures use a bakery stop, giving you a chance to buy food and wait for the next pickup. This is a practical break, but it is not an included lunch, so plan to pay for your own meal.

The day can involve returning toward Reykjavik or collecting people for the second activity before continuing to Thingvellir. That makes the tour less direct than a private transfer, but the drive gives you views of Iceland’s open countryside and volcanic scenery. The total schedule varies from 5 to 9 hours, so do not plan a tight evening appointment.

If you drive yourself, allow enough time for changing weather and road conditions. The second meeting point is at Thingvellir National Park. Park at Thingvellir Parking P5, then walk about 400 meters back along the road to the smaller car park where the Arctic Adventures vans are located. Be there at least 15 minutes before the 14:00 snorkeling start.

This timing matters. Snorkeling begins sharply at the stated time, and the gear fitting takes work. Arriving late could create stress for you and the group.

Silfra puts you between two tectonic plates

Silfra is the day’s headline act for many people. It is a water-filled fissure in Thingvellir National Park, a UNESCO World Heritage Site, where the North American and Eurasian tectonic plates are moving apart.

You are not swimming through a wide open lake. Instead, you float through a narrow underwater passage shaped by the earth’s movement. The water comes from filtered groundwater, giving Silfra its famous clarity and blue tones. In the right conditions, the water looks almost unreal, with visibility stretching far beyond what you might expect from a cold freshwater site.

The route has a gentle current, and your guide stays with the group. You wear a dry suit, hood, gloves, mask, snorkel, and other required equipment. The suit provides buoyancy, so you float rather than work hard to stay up. That helps explain why some first-time snorkelers feel more comfortable than expected.

Still, do not mistake the equipment for a free pass. You must be able to swim and feel comfortable in water. Your face and hands can feel cold, and your hair gets wet. The water itself is extremely cold, even though the suit reduces the chill across most of your body.

The guides spend time helping you into the suit and checking the fit. This is one of the most important parts of the experience. A poor fit can make the water feel colder and make movement awkward, so listen closely and tell the guide if something feels wrong.

Past departures have included guides named John, Nebo, Taz, Steven, Saira, Kevin, and Jónas. The guide on your date may be different, but the role is the same: keep the group together, explain the route, and help you stay calm and properly positioned in the water.

What snorkeling feels like in the water

The snorkeling route is gentle rather than athletic. You follow the guide along the fissure and look down into shades of blue, gray, and green. Because the water is so clear, the visual effect is stronger than the physical effort.

The dry suit also changes how you move. You may float higher than expected, and your body position can feel unfamiliar at first. The guide can help you adjust, and the water’s current carries you along parts of the route.

I would not book this expecting a warm-water snorkel or a relaxed swim where you can wander off alone. You stay with the guide and follow the group’s pace. The reward is the unusual setting, not tropical wildlife or a long free-swimming session.

The free underwater photos add real value. Your guide takes pictures during the snorkel, so you can concentrate on the experience rather than trying to manage a camera with cold hands. Ask how and when the photos will be delivered, since the supplied details confirm that photos are included but do not specify the delivery method.

Afterward, hot cocoa and biscuits help you warm up. Bring a towel and a complete change of clothes. A thin shirt and leggings under the suit can make changing easier, and warm layers for afterward are essential. You do not want to finish the most memorable part of the day and then sit cold in a van.

The guides are a major part of the experience

This tour has two separate activities, so you get two guiding styles. The caving guide handles the volcanic story and the underground route. The snorkeling guide handles equipment, water safety, group spacing, and the practical challenge of moving through cold water.

That division works well. A guide who is good at telling geological stories is not automatically the right person to manage a group in dry suits, and the reverse is also true. Here, a certified PADI snorkeling guide leads the water section, while a dedicated caving guide handles the tunnel.

The strongest guide moments come from small acts of care: checking that you are comfortable, helping with the suit, explaining what comes next, and assisting someone who tires in the water. One past departure included a guide towing a tired snorkeler part of the way while keeping the person with the group. That is the kind of support you want in a cold-water activity.

The guides also bring humor. Names and staffing change, but past departures have included enthusiastic leaders such as Weronika and Jónas. A friendly tone matters when you are trying to get into a stiff dry suit in chilly weather.

Price and value at $202

At $202 per person, this is not a cheap sightseeing outing. The price makes more sense when you count what is bundled: caving equipment, snorkeling equipment, certified guides, Thingvellir National Park admission, underwater photos, and hot cocoa with biscuits.

Hotel pickup and drop-off are available if you select that option, which can be valuable if you do not have a rental car. You also avoid arranging separate transport to Raufarholshellir and Thingvellir.

The real value is the combination. A standalone lava cave visit gives you an interesting underground geology lesson. A standalone Silfra tour gives you the more famous water experience. Combining them lets you compare two results of Iceland’s volcanic and tectonic forces in one day.

The compromise is time. You may spend part of the day in transit or waiting between activities, and the itinerary can stretch to 9 hours. If your priority is maximum time at Silfra, book a snorkeling-only outing. If you want variety and have only one day for these attractions, the combined tour earns its price.

Who should book this experience

This tour suits you if you want active sightseeing with a strong geology focus. It is especially good for couples or friends who want two very different experiences and do not mind a full day with several changes of clothing.

It also works for a first-time snorkeler who can swim and is willing to follow instructions. The dry suit provides flotation and warmth, and the guides stay close. Still, you need to be comfortable putting your face in cold water and moving with a group.

The tour is not suitable for non-swimmers, pregnant women, people under 150 centimeters or 45 kilograms, or children under 12. The supplied medical restrictions also include heart problems, respiratory issues, epilepsy, diabetes, high blood pressure, and other pre-existing medical conditions. If you have a medical condition, you need approval from a doctor before taking part.

You must read the snorkeling handbook before the tour. Sunglasses are not allowed, so leave them behind. Bring warm clothing, a towel, and a full change of clothes.

Should you book it?

Book this tour if you want Silfra’s clear water plus a genuine lava tunnel without arranging two separate excursions. The mix is memorable, the guides provide strong support, and the included photos and refreshments improve the value.

Skip it if you dislike cold water, enclosed spaces, outdoor changing, or long activity days. Also skip it if you need a flexible schedule around other plans. For everyone else who meets the physical requirements, this is a smart way to see Iceland from below ground and below water on the same day.

FAQ

How long does the tour last?

The activity lasts approximately 5 to 9 hours. The exact duration and starting times depend on availability and the selected option.

Where does the first activity begin?

The lava caving portion begins at Raufarholshellir Lava Tunnel. You should arrive 15 minutes before the scheduled 9:30 departure.

Where does the snorkeling begin?

Snorkeling begins at the Silfra meeting point in Thingvellir National Park at 14:00 on the stated schedule. Arrive at least 15 minutes early.

How do I find the Silfra meeting point?

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

Is hotel pickup available?

Hotel pickup and drop-off are available from selected Reykjavik pickup points if you choose that option when booking.

Do I need to bring snorkeling equipment?

No. Snorkeling gear and caving gear are provided. A certified PADI snorkeling guide and a caving guide also lead the activities.

Are underwater photos included?

Yes. The snorkeling guide takes underwater photos, and they are included at no extra charge.

Do I need to know how to swim?

Yes. You must be able to swim and feel comfortable in the water. The dry suit provides buoyancy, but it does not replace swimming ability.

What should I bring?

Bring warm clothing, a towel, and a complete change of clothes. A thin shirt and leggings can be useful under the snorkeling suit.

Can pregnant people or people with medical conditions join?

Pregnant people cannot participate. The tour also lists several medical restrictions, including heart problems, respiratory issues, epilepsy, diabetes, high blood pressure, and other pre-existing conditions. Medical approval from a doctor is required if you have a medical condition.