Silfra Fissure Snorkeling: What to Wear Under Your Suit

Layering Under Your Thermal Undersuit

The thermal undersuit provided by your operator is your primary insulation layer, but what you wear beneath it matters just as much. Start with a moisture-wicking base layer closest to your skin - merino wool or synthetic materials work best because they pull sweat away from your body rather than absorbing it. Cotton traps moisture and loses its insulating properties when wet, so avoid it entirely. Your base layer should fit snugly without restricting movement; loose clothing creates gaps where cold water can circulate.

Over your base layer, add a mid-layer fleece or neoprene shirt if the water temperature is particularly cold. The operator's thermal undersuit is typically 3mm neoprene, which provides substantial warmth, but an additional fleece mid-layer creates dead air space that traps body heat. Many experienced snorkelers in Iceland layer a lightweight rash guard as a base, then fleece, then the thermal undersuit. Keep layers form-fitting rather than baggy; bulky clothing compresses under pressure and loses insulating power. Test your layering combination before arrival if possible, or ask your guide upon pickup about conditions on the day of your tour.

Socks and Glove Options for Cold Water

The operator supplies neoprene gloves and boots, but the socks you bring determine whether your feet stay warm throughout the 5.5-hour outing. Wear thick wool socks or thermal diving socks specifically designed to withstand cold water exposure. Standard athletic socks compress and lose effectiveness; invest in a pair rated for water sports. Two pairs of thermal socks provide extra insulation if you have room inside the provided boots - the operator's boots are sized to accommodate this additional layer. Avoid oversized socks that bunch inside the boot, as wrinkles reduce insulation and cause discomfort during extended wear.

Regarding gloves, the operator provides neoprene mitts, but if you have particularly cold hands, consider bringing your own thicker diving gloves to wear underneath. Some snorkelers prefer neoprene gloves with individual fingers rather than mittens because they allow slightly more dexterity. Test the operator's gloves during your initial gear fitting - if they feel too thin or loose, mention this to your guide, who may offer alternatives. The key is ensuring a snug fit with no water circulation inside the glove. Ensure your wrists sit fully covered where the thermal undersuit ends and the glove begins, with no exposed skin to the water.

Full thermal layering and dry suit setup for Silfra snorkeling

Glasses, Contact Lenses, and Vision Underwater

If you wear glasses or contacts, contact lenses are the practical choice for snorkeling in Silfra. The operator provides a standard snorkel mask, which cannot accommodate prescription glasses inside. Soft contact lenses work well in the cold glacial water, though some people find the intense cold briefly uncomfortable when they first enter the water. If you wear contacts, bring a spare pair and keep them in your bag at the starting point. Many guides recommend wearing contacts rather than attempting to snorkel without correction, as you'll want to see the geological formations and wildlife around you.

If you strongly prefer not to wear contacts, discuss prescription mask options with the operator before your tour date. Some outfitters offer masks with corrective lenses for an additional fee, though this must be arranged in advance. Without vision correction, the glacial water clarity becomes a disadvantage rather than a benefit. Bring your contact lens case, solution, and glasses for after the snorkel. Store your everyday glasses securely in your dry bag at the site so they are not damaged or lost during the experience.

Long Hair Management and Mask Fit

Long hair and snorkel masks present a practical challenge: hair caught under the mask seal allows water to seep in, creating leaks that flood your snorkel. Before arriving, plan to wear your hair in a tight braid or bun secured with waterproof elastics. Avoid loose ponytails, which shift as you move in the water and catch in the mask's edge. Braiding pulls hair completely away from your face and neck, leaving the mask perimeter clear for a watertight seal. If your hair is very thick or long, two braids positioned on either side of your head provide the best result.

On the day of your tour, ask your guide to double-check your mask seal before you enter the water. The guide will press the mask against your face and confirm that no hair sits under the silicone edge. This small step prevents frustrating water leaks during your snorkel. If water does enter your mask despite precautions, signal your guide immediately - they are trained to help you clear it. Wearing a rash guard with a collar or hood can help keep stray hairs in place, providing an extra barrier of security for keeping your mask sealed throughout the experience.

Documents, Waivers, and Medical Requirements

Before your tour, the operator requires you to complete a liability waiver and medical screening form. Bring a valid passport or government-issued ID for identification purposes. You should receive these documents when you book; review them carefully and fill them out completely before your pickup time. Medical questions typically ask about heart conditions, asthma, ear problems, or recent surgery. Answer honestly, as snorkeling places physical demands on your body through cold exposure and breath control. If you have any medical concerns, contact the operator in advance rather than waiting until the morning of your tour.

Bring printed or digital copies of any medical certifications if relevant, such as a PADI diving certification (though this is not required for snorkeling). The operator's PADI-certified guides conduct a safety briefing and will ask about your swimming ability and snorkeling experience. If you have medical conditions not covered by the standard form, provide documentation to your guide at pickup. Keep your ID, signed waiver, and any medical records in a waterproof bag that stays with you at the site. The operator needs this information on file before you enter the water.

Cameras, GoPros, and Valuables at the Site

Your guide takes complimentary underwater photos during the snorkel, so you don't need to bring a camera into the water. If you wish to bring your own GoPro, phone, or underwater camera, verify that the operator allows personal devices before your tour date. Not all operators permit this, and equipment damage or loss is your responsibility. Waterproof cases designed for GoPros can withstand the cold water, but they reduce image quality compared to a dedicated underwater camera. Battery life shortens significantly in cold water, so charge your device fully before leaving Reykjavik.

Store your valuables, dry clothes, and personal electronics in a secure location at the tour's base or in your vehicle. The operator typically provides a changing area, but lockers or attended storage varies by outfitter. Bring only essentials in a waterproof dry bag: your ID, any required medical forms, a small amount of cash, and your phone if absolutely necessary. Do not leave valuables unattended in the changing room. After snorkeling, you'll want a full change of dry clothes, so pack your bag accordingly and keep it separate from the snorkeling gear. Ask your guide where secure storage is available before you change into your thermal undersuit.

Towels and What to Bring for After the Snorkel

Bring at least one large towel to the site, as the operator does not provide towels as part of the tour. A microfiber towel dries faster than cotton and takes up less space in your bag. You'll need this immediately after exiting the water to dry off before returning to the changing area. Consider bringing two towels if you want one for drying your hair and another for your body. The operator provides hot cocoa and cookies after snorkeling to help warm you, but having your own towel speeds up the warming process.

Pack a complete change of warm clothes in your vehicle or secure bag: dry underwear, warm socks, a sweater, and long pants. Avoid jeans, which are cold and uncomfortable when damp. Bring a warm hat and gloves for the ride back to Reykjavik, as you may still feel chilled even after the hot cocoa and towel-drying. A plastic bag for wet clothes keeps your dry bag from getting soggy. Wear slip-on shoes or sandals so you can remove them easily before putting on the thermal undersuit, then slip them back on afterward without struggling with laces when your hands are cold.

Before you book