Choosing a Freediving Mask: Low Volume, Fit and Lenses

A good freediving mask is low volume, seals on your face without the strap holding it on, and has a soft nose pocket you can pinch easily. Low volume matters because every bit of air inside the mask has to be equalised with air from your lungs, and at depth that air is precious. Fit matters more than any feature: the right mask is the one that seals on your face, not the one that worked for your friend.

Why a freediving mask should be low volume

The air in your mask follows Boyle’s law like every other air space: it’s squeezed to half its volume by 10 metres and to a quarter by 30 metres. To stop the mask pressing into your face, you breathe a little air out through your nose as you descend. That air comes from your lungs, which are shrinking too. Our guide to pressure and depth shows how quickly this happens.

A big scuba-style mask can need noticeably more air to equalise. On a shallow dive that hardly matters. On deeper dives, especially once you start using a mouthfill, every bit of air spent on the mask is air you can’t use for your ears. If you don’t add enough, you get the bruised, bloodshot look of mask squeeze, covered in mask squeeze and sinus squeeze.

Low-volume masks have another benefit: the lenses sit close to your eyes, which tends to give a wider field of view for the size. Manufacturers sometimes quote internal volume in millilitres. Lower is better, all else being equal, but only if the mask fits.

Freediving mask features that matter

• Soft nose pocket. You’ll pinch your nose for Frenzel equalisation, often hundreds of times a session. The pocket should be soft and easy to seal between thumb and finger.
• Silicone skirt. Soft, flexible silicone that sits on the face without hard edges. A black skirt cuts glare and side light, which many freedivers and photographers prefer. A clear skirt lets more light in and feels less closed-in, which suits some nervous beginners.
• Lens. Tempered glass is standard. Twin-lens masks are usually the ones that accept prescription lenses; single-lens masks give an uninterrupted view.
• Lens colour. Clear lenses are the default for good reason. Tinted or mirrored lenses cut glare at the surface but darken your view at depth, and mirrored lenses stop your buddy seeing your eyes, which is one of the ways a buddy spots trouble.
• Frame or frameless. Frameless masks bond the skirt straight to the lens. They’re often lower in volume and fold flatter for packing.
• Strap. Silicone straps are standard. Neoprene strap covers are kinder to long hair and easier to adjust. Many freedivers keep the snorkel loosely attached with a keeper, and our snorkel guide explains why a simple one works best.

How to fit-test a mask before you buy

Do this in the shop, or as soon as an online order arrives and before you remove any tags.

1. Push your hair off your forehead and let the strap hang loose in front of the mask.
2. Place the mask gently on your face and look straight ahead.
3. Breathe in gently through your nose and let go. A mask that fits will stay on by suction.
4. If it falls, check where the air came in: the forehead, the sides, or under the nose.
5. Pinch the nose pocket. You should be able to seal your nostrils easily, without the frame digging in.
6. Check for pressure points, especially on the bridge and the tip of your nose.
7. Look up, down and sideways to judge the field of view.
8. Finally, put the strap on, snug but loose enough that the skirt isn’t distorted. Water pressure holds the mask on at depth; the strap only keeps it in place.

A moustache can break the seal under the nose. You can trim it, accept a small leak, or use a little lubricant on the hair. Check the mask maker’s advice first, because petroleum-based products can degrade silicone over time.

Buying online in India makes fit-testing harder. Where possible, try masks at a dive shop on a trip, or buy from sellers with a clear return policy. Buying freediving gear in India explains why the mask is usually the first thing to buy.

Preparing a new mask so it doesn’t fog

New lenses usually carry a thin factory residue that makes them fog. Before the first dive, clean the inside of the lens following the manufacturer’s instructions. Many people use a dedicated mask cleaner or a mild, non-gel toothpaste rubbed in gently and rinsed off well; don’t use anything abrasive on coated lenses. Some divers burn the residue off with a lighter. We don’t recommend it, as it can damage the skirt and some lens coatings.

Before each dive, use a defog solution, diluted baby shampoo or old-fashioned spit, then rinse lightly. Put sunscreen on well before you dive and keep it off the area where the skirt seals; it smears the lens and stings badly when it reaches your eyes.

Goggles, nose clips and pool training

For static and dynamic training in the pool, many freedivers wear swimming goggles and a nose clip instead of a mask. It’s comfortable and cuts drag. But goggles have no nose pocket, so you can’t equalise them. In a shallow pool that’s fine. In a 4–5 metre diving well you’ll already feel them pressing on your eyes, and in open water they don’t belong on any dive below a couple of metres. Some divers who train very deep use fluid goggles, filled with liquid instead of air, but that’s a specialised tool to learn with an instructor.

Prescription options

If you wear glasses, your options include masks that take corrective lenses in set steps, custom-made lenses, and stick-on lenses. Contact lenses work for some people but carry risks of eye infection and losing a lens mid-dive. Our guide to prescription masks covers the choices, and your optometrist should be part of the decision.

Looking after your mask

• Rinse it in fresh water after every session; dried salt crystals scratch lenses and stiffen silicone.
• Dry it in the shade. Clear silicone yellows with sun exposure over time.
• Store it in its hard box, not squashed in a bag under fins and weights. A deformed skirt won’t seal.
• Keep it out of hot cars and off sunny boat decks between dives.

Safety: Equalise your mask as well as your ears by breathing a little air out through your nose as you descend. If you feel pressure on your face or eyes, stop descending and add air, or turn. Choose clear lenses so your buddy can see your eyes, and never freedive without a trained buddy watching you.

Before you buy your first mask

Make a shortlist of low-volume masks with soft nose pockets, fit-test every one, and pick the one that seals best on your face, whatever its colour. Then practise pinching and equalising with it on land until the movement is automatic. The freediving.in community is coming soon. Stay tuned.