How to Choose a Dive Mask: Fit Test, Types, Fogging and Prescription Lenses

Human eyes can't focus in water, so without a mask everything looks blurred. A dive mask traps a pocket of air in front of your eyes so you can see clearly. It also covers your nose, which is the key difference from swimming goggles. You need your nose inside the mask so you can exhale into it to equalize pressure as you descend. Never dive in swimming goggles; they can cause painful "eye squeeze".

How a dive mask is built

• Lens: tempered safety glass (look for "tempered" printed on it). Plastic lenses scratch and are not suitable for scuba.
• Skirt: the soft seal against your face, made of silicone. Good masks use high-grade, hypoallergenic silicone.
• Frame: holds the lens and skirt; frameless masks bond the skirt directly to the lens.
• Nose pocket: lets you pinch your nose to equalize, even with gloves.
• Strap and buckles: silicone straps or comfortable neoprene "slap straps"; quick-adjust buckles are easiest.

Types of dive masks

Type	Pros	Cons	Best for
Single lens	Wide, uninterrupted view; often low volume	Can't take prescription lenses easily	Most divers, photographers
Double (twin) lens	Can fit prescription lenses; often very low volume	Bar in the middle of your view	Divers needing vision correction
Frameless	Low profile, folds flat, easy to pack	Slightly less rigid	Travel, backup mask
Side-window / panoramic	Wide peripheral view	Higher volume, harder to clear, more reflections	Some snorkelers
Full-face snorkel masks	Not for scuba; there are also safety concerns for snorkeling (CO₂ build-up)		Avoid for diving

Low volume vs high volume

Low-volume masks sit close to your face. They need less air to clear and equalize and give a wider field of view per millimetre of lens. Most modern scuba masks are low volume.

Clear vs black skirt

Clear skirts let in more light and feel less claustrophobic, which is great for beginners. Black skirts reduce glare and help focus, and photographers and divers in bright tropical sun often prefer them.

The fit test (the most important part)

A mask that fits won't leak, even with a relaxed strap. Test it in the shop:

1. Move your hair away from your forehead.
2. Place the mask gently on your face without using the strap.
3. Inhale gently through your nose and hold.
4. Let go. The mask should stay stuck to your face with a good seal all the way round.
5. Now fit the strap loosely and check for pressure points on your nose and forehead. Wear it for a couple of minutes.

If air leaks in, it will leak water too. Try another model. Faces vary a lot, and brand has little to do with fit.

How to stop your mask fogging

Prepare a new mask

New masks have a thin film of silicone residue from manufacturing that causes stubborn fogging. Remove it before the first dive:

• Scrub the inside of the lens with non-gel, non-whitening toothpaste or a dedicated mask cleaner, rinse, and repeat 2–3 times; or
• Carefully "burn" the film off with a lighter flame (for tempered glass only, never touching the silicone). This is controversial; follow the manufacturer's advice, as some forbid it.

Before every dive

• Apply a few drops of anti-fog gel or spray, or diluted baby shampoo, spread it on the inside of the lens, then rinse lightly.
• Keep the mask off your forehead. The warm air from your face fogs it, and it can be knocked off by waves.
• Don't touch the inside of the lens with your fingers.
• Spit works too: rub it on the dry lens and rinse briefly.

If it fogs underwater, let in a little water, swirl it around, and clear the mask. See what to do if your mask fogs.

Prescription masks

Water magnifies objects by about 33%, so some people with mild short-sightedness see fine underwater. For others, options include:

• Soft contact lenses under a normal mask (keep your eyes closed when clearing a flooded mask). Daily disposables are best, in case you lose one.
• Stock corrective lenses: many twin-lens masks accept pre-made negative (short-sighted) lenses in 0.5 steps, often available the same day.
• Custom prescription lenses bonded or ground to your prescription, including astigmatism and bifocals, from specialist optical labs.
• Bonded "reader" lenses at the bottom of the lens for reading your computer (useful from about age 45).

Buy or rent?

Buy. A mask is personal, hygienic, affordable (US$40–120 for an excellent one) and the item most likely to spoil your dive if it doesn't fit. It's the first item on our first gear to buy list.

Care and maintenance

• Rinse in fresh water after every dive and let it dry in the shade.
• Store it in its hard case, away from sunlight, which yellows silicone.
• Don't store it touching black rubber or neoprene; clear silicone can discolour.
• Check the strap for cracks before trips; carry a spare strap.

Frequently asked questions

Can I use swimming goggles for scuba diving?

No. Goggles don't cover your nose, so you can't equalize the air space and they will squeeze your eyes painfully as you descend.

Why does my dive mask fog up?

Fog forms when warm, moist air from your face condenses on the cooler lens. New masks also have a manufacturing film that makes fog cling. Clean new lenses properly and use anti-fog before each dive.

Are full-face masks good for scuba?

Consumer full-face snorkel masks are not designed for scuba. Professional full-face diving masks exist but require special training.