How to choose a snorkel mask: a step-by-step guide
By SnorkelMatch, last checked . How we check
Choosing a snorkel mask is five small decisions in a fixed order. Get them in order and most of the trouble people have in the water, leaks, fog, a mask that feels wrong, is settled at home. Each step links to a guide with the details and the sources.
Step 1: measure your face
Put the zero of a ruler at the bridge of your nose, level with your eyes, and read it at the bottom of your chin, mouth closed. That single length is what the full-face makers’ charts use; Ocean Reef, for example, says to measure “from your nose bridge, to the bottom of your chin”[1]. It takes a minute and you only do it once. How to hold the ruler and read it is in the size chart guide.
Step 2: pick a type
There are two: a full-face mask, which covers your whole face and has no mouthpiece, and a traditional mask over your eyes and nose with a separate snorkel. The choice turns on a few facts about you:
- A mouthpiece makes you gag or your jaw ache: that points toward full-face. See full-face vs traditional.
- Beard or mustache: a beard crosses a full-face seal; a mustache crosses a traditional one. See the beard guide.
- Glasses or contacts: glasses cannot go under a mask, and the CDC advises removing contacts before swimming[7]. Both types have prescription options; see the glasses guide.
- A child: follow the maker’s age and size limits and read the kids’ guide.
- A weaker swimmer: a traditional mask and snorkel come off in two quick moves; Hawaii’s ocean safety page lists difficulty removing a mask among the concerns it studies[4].
- You want to dive down: a traditional mask lets you breathe out through your nose to even the pressure[3].
If you would rather not weigh these yourself, the mask quiz asks six questions and shows the reasons for its answer. If you lean toward full-face, read the full-face safety guide first: it quotes the CPSC warning of March 2026 about one model[5] and Hawaii’s guidance[4].
Step 3: read your size on that maker’s chart
Full-face masks are sized by the maker’s own chart, and makers draw their lines in different places. Decathlon splits its adult sizes at 12 cm (4.7 in)[2], Ocean Reef at 11.5 and 12.5 cm[1]. Type your measurement into the size finder to see every chart we could read at once, with a warning when you are close to a line. Traditional masks are mostly one adult size, with kids’ models by age[9].
Step 4: test the seal at home
When the mask arrives, test it before anything else. For a traditional mask, hold it on without the strap, breathe in gently through your nose and let go; DAN says a mask that fits “should seal to your face and not fall off even without the mask strap in place”[3]. For a full-face mask, check that there is no gap between your chin and the skirt[2]. Set the strap high and snug, not tight: U.S. Divers warns that a mask cinched too tight can lift at the sides[6]. Full steps are in the seal test guide.
Step 5: practice on land, then in shallow water
Hawaii’s ocean safety page asks you to practice breathing through the snorkel and removing the mask on your own before you get in the water, and never to use the gear in the water if either feels difficult on land[4]. Then try it standing in calm, shallow water with a buddy. If a new glass lens fogs, scrub off the factory film as the maker describes and use an anti-fog product[6][4]; the fog guide has the order.
On the day
- Snorkel with a buddy and choose lifeguarded beaches when you can[4][8].
- Check conditions and ask lifeguards before going in; skip it if the surf, wind or current is up[4].
- Consider a floating vest or belt made for snorkeling[4].
- No alcohol before or during[8].
- If you feel dizzy, disoriented or get a headache, stay calm, take the gear off and get out of the water safely[4].
What we do not do
We did not test masks and we do not name a best one. We put the makers’ charts side by side, quote the official sources, and show you how to check the fit yourself, so the decision rests on your face and your swimming. How we check explains the method.
Before buying any full-face mask, read the CPSC warning of March 2026 for the model it names (linked in the sources below).
Questions people ask
What is the best snorkel mask?
We did not test masks, so we do not name one. The mask that suits you is the one of the right type for your face and swimming, in the size the maker's chart gives for your measurement, that passes the seal test on your face.
What should I look for in a snorkel mask?
The right type for you (full-face or traditional), the maker's size for your measurement, a skirt that seals on your skin, a strap that sits high and snug, clear instructions from the maker, and a seller who accepts returns.
Should I rent or buy?
Renting avoids buying the wrong size but leaves fit to chance on the day. If you rent, Hawaii's ocean safety page advises renting only from a licensed vendor, talking to them about using the equipment properly, and making sure the mask fits you correctly.
How long before my trip should I buy?
Early enough to do the seal test at home, practice breathing and taking the mask off, and return it if it does not fit, within the seller's return window.
Sources
- [1]Ocean Reef (manufacturer): Aria QR+ size chart
Measure "from your nose bridge, to the bottom of your chin"; XS (kids) up to 10 cm, S/M 10-11.5 cm, M/L 11.5-12.5 cm (Aria QR+ only), L/XL 12.5-14 cm; "Try the mask on to be sure of fit". Read on 2026-10-09.
- [2]Decathlon (manufacturer): A Guide to Selecting the Perfect Size for Your Easybreath Mask
Measure "the distance between your chin and your eyes": less than 12 cm (4.7 in) S/M, more than 12 cm M/L; "If there's no space between the silicone skirt and your chin, then this is the mask for you." Read on 2026-10-09.
- [3]Divers Alert Network (DAN): Mask Squeeze (Facial Barotrauma)
"You should be able to achieve an appropriate seal by gently placing the mask on your face and inhaling through your nose. The mask should seal to your face and not fall off even without the mask strap in place. It is not unusual for a small amount of leakage to occur while diving, especially if you have facial hair." Equalizing a mask means "adding air to the space in the mask (by exhaling through your nose)". Read on 2026-10-09.
- [4]Hawaii Department of Health, Hawaii Ocean Safety: Snorkeling Safety
"Always snorkel with a buddy"; "Use an anti-fog product in your mask"; "Make sure your face mask fits properly and does not leak"; "Consider using a floatation device appropriate for snorkeling, such as a floating vest or belt"; "If you become dizzy, disoriented, or begin to feel a headache, you may be experiencing carbon dioxide buildup in your snorkel gear"; on full-face masks: "there is currently not enough evidence to show a direct increase in risk", theories include "Carbon dioxide buildup", "Difficulty removing the mask", "Poor fit allowing leaking of water"; "breathe only through your nose using slow, calm breaths"; "Practice breathing through the snorkel and removing the mask on your own before you get in the water."; "If you are renting equipment, rent only from a licensed vendor, and talk to them about using this equipment properly." Read on 2026-10-09.
- [5]U.S. Consumer Product Safety Commission (CPSC): Warning about one full-face snorkel mask model, March 5, 2026
The notice says the mask "can cause consumers to experience labored breathing, causing loss of consciousness or excess fluid in the lungs that can lead to drowning" and "can give rise to increased levels of carbon dioxide"; CPSC "has received reports from five consumers who had trouble breathing, felt light-headed or lost consciousness"; "About 84,000 of these full-face snorkel masks were sold from March 2019 through February 2026". See the notice for the affected model. Read on 2026-10-09.
- [6]U.S. Divers (manufacturer): Care & Maintenance: Masks
"During the manufacturing process, a thin film of silicone will develop on the glass lens. This film of silicone will cause rapid fogging"; scrub the lens "with a mild abrasive. A paste toothpaste is ideal"; "Mask fogging is a normal occurrence, even after the film of silicone has been removed."; "Some after after-market anti-fog agents contain formaldehyde, alcohol, or other substances that may damage the plastic materials"; a mask "cinched too tightly" can lift at the sides; "Do not use any type of alcohol, solvent or petroleum based substances to clean or lubricate any part."; after snorkeling, soak "in warm fresh water (not over 120°F)" and store "in a cool, dry and protected place away from high heat or direct sunlight." Read on 2026-10-09.
- [7]Centers for Disease Control and Prevention (CDC): Healthy Habits: Keeping Water Away from Contact Lenses
"Contact lens wearers should remove lenses before water activities such as showering or swimming."; "If water touches contact lenses for any reason, take them out as soon as possible."; "For those who are actively involved in swimming or other water sports and concerned about being able to see well enough without wearing lenses, prescription goggles may be a good option." Read on 2026-10-09.
- [8]Centers for Disease Control and Prevention (CDC): Preventing Drowning
"Drowning happens in seconds and is often silent."; "Designate a responsible adult to supervise closely and constantly when children are in or near water"; "Life jackets should be used by children for all activities while in and around natural water."; "Always swim with a buddy."; "Avoid drinking alcohol before or during swimming"; "Do not hyperventilate before swimming underwater or try to hold your breath underwater for long periods of time." Read on 2026-10-09.
- [9]U.S. Divers (manufacturer): Snorkeling masks collection
An adult mask "features a one-size-fits-all design"; kids' models are labelled "Designed for ages 6+" and "Designed for ages 4+". Read on 2026-10-09.
Related guides
- Snorkel mask size chart: how to measure your faceWhere to put the ruler, how to read it, and the makers' published size lines side by side, in inches and centimeters, with what to do near a line.
- Full-face vs traditional snorkel mask: how to chooseHow each type is built, how you breathe in it, and which one suits a beard, glasses, a gag reflex, a child or a weaker swimmer, with sources.
- Full-face snorkel mask safety: what official sources say and how to lower the riskThe CPSC warning of March 2026, the Hawaii Department of Health, DAN and three studies, quoted and linked, plus the practical steps they recommend.
- How a snorkel mask should fit: the 30-second seal test at homeThe no-strap sniff test, what a good fit feels like, where leaks come from and how tight the strap should be, before you ever get in the water.
Last checked October 9, 2026. General information from official sources, not medical, safety-training or professional advice. Snorkeling carries real risks, including drowning: never snorkel alone and follow the manufacturer's instructions and local lifeguard guidance.