a female snorkeler on the surface of very clear blue water

Why Does A Snorkel Mask Fog?

Snorkeling a very visual activity. The practice of surface viewing over corals, while watching the colorful marine life attracts millions every year.

Snorkeling isn’t without its issues, but one of the biggest concerns is about the mask fogging up. If you can’t see much it ruins the experience.

The problem is curable, but understanding why it fogs in the first place helps make the preparation more likely to be done. So, why does a snorkel mask fog?

A snorkel mask fogs up because of a combination of moisture and dirt on the lens. Moisture condenses on the lens as a result of temperature difference, attaching to oils, imperfections, or dirty glass. A well cleaned glass lens will prevent the moisture attaching to the lens and cascade down the mask, before pooling at the bottom. Various techniques are used to reduce the surface adhesion of the moisture to keep the mask lens clear.

A continually fogging mask that you’ve bought or rented can be a source of extreme frustration, completely denying you a sustainable snorkeling adventure.

The problem isn’t difficult to prevent at all and taking the time to pretreat the mask with some basic maintenance will help you enjoy the snorkeling all the more.

a female snorkeler over coral

How Exactly Does A Snorkeling Mask Fog?

But for the small troublesome act of breathing a snorkeling mask might never fog up.

Air temperature and water temperature are different. The moisture inside the mask from either breathing or a wet face collects within the mask and looks for something to condense on.

This tends to be the lens, which is dirty.

Anything from manufacturing residue, dirt, grease, oils, or even imperfections and scratches will collect the moisture and fog the mask, hampering the ability to view through the lens.

The mask needs to be cleaned of all manufacturing residues and be completely clean otherwise it will continually fog.

Do All Snorkel Masks Fog Up?

Most will yes because it’s not just a manufacturing issue.

Snorkeling mask manufacturers can make claims about their anti-fogging lens’ and that may be true, but if dirt, oils, or greasy fingerprints are on the internal lens then the mask will fog up.

The moisture from your breath and off your wet face will make a moisture rich environment within the mask and it will collect on the internal lens.

a snorkeler in the sunlight

Some Simple Tips For Prevention of Mask Fog

If you get a new snorkeling mask you may think that you can just clean it and start snorkeling. However, the manufacturer leaves a coating on the inside of the lens which needs to be removed.

If this coating isn’t removed your mask will continually fog. The coating is very hygroscopic and will soak up moisture. Your mask will fog no matter what you do, or whichever brand of anti-fog spray you use.

There are 2 methods.. One involves taking a lighter to the lens, but there is a common treatment that you should try first.

Pre-treatment Of A Snorkeling Mask

The very first time you get a mask to use, you should take the pretreatment steps to help minimize any potential fogging in the future.

  1. Remove any dirt, grit, or items that scratches. Flush out anything that will scratch the glass. Dry both sides of the lens.
  2. Rub some ‘non-gel’ basic toothpaste onto both sides
  3. Wash your hands and rub the toothpaste over every area of the lens using small circular motions.
  4. Thoroughly rinse the lens of the mask. Then dry both sides of the lens.
  5. Repeat 3 or 4 times.

Pretreating a mask isn’t difficult, and only takes a little while, but it is entirely worth it.

a female snorkeler on the surface in shallow water

Tips On Keeping Your Mask From Fogging

The main reason a mask fogs is because of moisture and the dirt it can collect on, so the main tips are on how to keep the moisture out, and the lens clean.

Moisture within the mask that cannot collect on lens dirt will cascade down the mask lens leaving it transparent for a snorkeling session.

As moisture will attach itself to anything on the lens, substances that clean the lens will work to prevent the mask from fogging. An age old trick is to use saliva, baby shampoo, or even potatoes. Reducing the surface tension on the lens will prevent condensation.

Clean your mask – This isn’t just for prevention but can help keep your mask useable for many years. It’s just good practice. Don’t throw the mask into the cupboard with sand, grit, and oils on the lens. Keep using the toothpaste trick often to keep the oils and grit away. Flush away the contaminants in water and wrap the mask in a towel and protect it. Use nothing on the lens that will scratch it so that moisture can attach itself to.

Anti fog spray – Although you can use professionally designed spray, you could also use a drop of baby shampoo. Anything designed to break surface adhesion will do. Just carry a small bottle of diluted baby shampoo around in your snorkeling kit, or wash bag. Alternatively, get some professional spray and rub it onto the lens. Using a microfiber cloth is best as it keeps the oils of your fingers off the lens.

Have a dry face  – Moisture doesn’t need to come from your breath, it can come from droplets on your face. If it’s possible, dry your face with a towel prior to putting on the mask. Also, dry the skirt of the mask.

Keep the mask on – If at all possible, try to keep the mask on. The more you keep taking it off and on, the more opportunity there is for moisture to get inside and increase the risk of fogging.

Breathe through the mouth – Once the mask is in the position you will have to breathe through your mouth. Try not to use your nose, and break the seal of the mask.

Using saliva – As snorkeling is an adventure, you are not always near a piece of kit. You can use saliva in the same way as you put toothpaste on the lens. Spit onto the lens and rub it on before washing it off.

Maintenance – After every use, make sure your mask is rinsed off in luke warm water. Get rid of all the grit, sand, and oils and flush away. Include the skirt of the mask. Once cleaned pad it down with a towel so it is left dry as well as clean.

a female snorkeler face to face with a turtle

Final Thoughts – Parting Waves

Many things can turn a great snorkeling adventure into a frustrating annoyance. Blisters will certainly do that, as will a mask skirt that continually leaks.

Snorkeling is primarily a visual experience, with the wonders of marine life available to all.

The one thing that will guarantee frustration is a mask that fogs and prevents the snorkeler from experiencing the colorfest that is aquatic life.

Fogging masks occur due to the condensation of moisture vapor on the inside of the mask lens which is at a different temperature than the outside. Moisture from a human being is warmer than the surrounding contents.

The vapor then attaches to the dirt and imperfections of the lens glass and prevents 100% visibility. 

A regime of keeping the glass clean and dirt free, as well as keeping the surface hygroscopic will prevent the mask from fogging.

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