How to Keep a Snorkel Mask from Fogging

Cameron Profile Picture

Expert: Cameron – I have been snorkeling for over two decades and diving for the past three years all around the world from the Red Sea to the Gulf Coast to out West in the Pacific Islands. During this time, I have been shown many techniques on upkeeping your snorkeling gear and have learned what is necessary and dangerous to use on your snorkeling mask.

Your mask fogging up can be an incredible issue when in use.

Not only does it obstruct your vision, but having to clear it while underwater can be dangerous if you are in a precarious situation or have a difficult time multi-tasking while in or underwater.

Having a proper diving instructor to teach you how to clear your mask if this is an issue.

The best way to prevent fog in your snorkel mask is to apply toothpaste or a commercial defogging agent to a clean lens and rinse off in fresh water making sure to leave a small film of residue on the surface to ensure no moisture will accumulate on the inside of the mask while in use.

But why does a snorkel mask fog up in the first place?

Preventing Fog in Snorkel Mask

There are two scenarios that you will come across.

Prepping a brand new snorkel mask and prepping a snorkel mask that you have already used.

Prepping Your Mask for First-Time Use

I have expanded on steps to ensure the first use of your snorkel mask does not result in a negative experience.

1: Wash Your Hands

Washing Hands

This is important when starting with a new mask since your hands tend to have oils on them that you do not want applied to your new mask.

Even if you decide to not touch the lens with your fingers at all it is still important for the small instance they end up on the mask.

2: Dry Your Mask and Lens

Dry Snorkel Mask

Try using a soft towel or microfiber cloth in case your mask is already wet.

3: Apply Standard White Toothpaste to Lens

Apply Toothpaste to Snorkel Mask

Apply a pea sized non-gel standard white toothpaste to the inside and outside of the mask lens.

Ensure that it is standard white, I use (and what I have seen many dive masters use) Sensodyne Pronamel toothpaste (for sensitive teeth); this is usually a safe bet since this type of paste does not have anything extra inside that could put micro scratches on your mask.

Rub it in small circles clock-wise around the inside and outside of your lens with your finger, or a SOFT bristled brush.

4: Rinse the Mask Thoroughly

Rinse Snorkel Mask

Rinse your mask thoroughly in fresh water with your finger, brush, or tool of choice to remove all paste that has been added.

5: Repeat Process 5-7 Times

Some may not find this necessary, but we are ensuring here that all of the oils left over from the manufacturer are removed before the first time we use it.

Just be sure to repeat until you feel the job is finished.

I have also heard to leave the toothpaste on overnight to draw out any extra residue from the factory; I have not had to do this but it is worth the try (I have not heard it to damage a mask).

6: Apply Defogging Agent Before Each Use

Snorkel Mask and Toothpaste

Apply the agent of choice on the inside section of the snorkel mask lens only.

Rinse off and put your mask on.

I have seen many different items used; each has their benefit and need depending on the mask you have purchased.

I will go over all agents used after this next prep instruction for defogging your used snorkel mask.

Prepping Your Current Mask

Prepping a current mask that you have already used, or even a used diving mask is pretty much the same steps depending on your preference.

Knowing that the factory oils are already removed from the mask will tell you where to start.

If the factory oils are already removed follow these steps, if you are not sure just treat it like you are cleaning a brand-new mask, with one added step.

1: Wash Your Hands

Just like our previous explanation, it is important to remove any oils or debris from your hands before we begin.

2: Rinse Off Your Mask in Fresh Water

This is added for the off chance that the mask still has residue from its last use or possible sand in any crevasses that could come up and get stuck in our paste while applying causing micro scratches.

3: Dry Mask and Lens

Dry your mask and lens preferably with a microfiber cloth.

4: Apply Standard White Toothpaste to Lens

Just like before, standard white toothpaste is a wonderful and cheap choice that you most likely already have lying around to use.

Apply a pea sized spot on both the inside and outside of the lens and rub with your finger or soft bristled brush in small clockwise circles until coated.

5: Rinse Mask and Lens Thoroughly

It is not very fun getting any toothpaste in your eye so it is important to rinse your mask as best you can before use.

Even if you do get some in your eye however, it is pretty much the same as salt water so do not fret you will still be able to see.

6: Apply Defogging Agent Before Each Use

Depending on your solution of choice, apply it only on the inside of the lens and rinse off before each use.

All Methods of Preventing Fog in Snorkel Mask

As those in the American South would say ‘There is more than one way to skin a cat’ (metaphorically); and the same goes with preventing fog inside your snorkel or diving mask.


This is my go-to solution for any fogging; since using toothpaste I have not had any fogging issues deep diving, night diving, or snorkeling.

Apply a pea sized amount on the inside of your lens and rub it around in small clockwise strokes until covered.

Rinse off in the water (some say fresh water, but I rinse it in the sea) and head out to your adventure.

Repeat for each use.

Commercial Defogging Agents

The drawback here is that these agents can be quite expensive, especially when purchasing from a dive shop.

Spray Solution

Spray solutions are not very different from those you would get for your reading glasses.

Spray into the mask and use a clean microfiber cloth to coat and disperse the solution throughout the inside of your mask.

Rinse off in fresh water, do not use sea water.

Repeat for every use.

Anti-Fog Gels

The benefit of these gels is that it also used for cleaning your mask.

Apply a pea sized drop to each side of your lens and rub in with your finger or tool of choice in small clockwise circles.

Rinse off in fresh water twice making sure to leave a small film of residue from the application.

If you rinse off all the solution it will not work.

I would recommend applying before each use, but I have seen some divers apply only once and it works throughout the day.

Baby Shampoo

Apply a few drops to your mask lens and coat the entire lens.

Rinse in fresh water but be sure to leave a small film of residue on the surface or it will not work like the anti-fog gels.

Reapply before each use.

Dishwashing Detergents and Glycerin Soaps

Apply a few drops in your mask lens and coat the entire lens.

Rinse in fresh water but still leave a small film of residue on the surface, like our previous two solutions it will not work if the entire solution is rinsed away.

The advantage is that you probably have some of this with you on your adventure and can easily be obtained at any convenient store for a cheap price.

The disadvantage is that if you get water inside your mask you risk losing the solution and can fog up.

Another big disadvantage of this is that if the solution gets into your eyes when water comes in it can really burn; be very cautious when using this and be sure your mask fits properly.

The Flame Trick

One not mentioned before is this flame trick.

Most dive shops can due this for you if you are worried about putting a flame to your new mask.

If you are unsure if your lens is the correct type for this and you are not at a dive shop, consult your instruction manual for the mask or google to brand to ENSURE YOUR LENS IS NOT PLASTIC because it will just melt the lens.

How to Use a Flame to Prevent Fog in a Snorkel Mask

Run the tip of the flame over the entire inside of the lens, ensuring to keep away from the edges to not melt the silicone skirt, until the lens turns black (this is a soot coating, (DO NOT OVERHEAT YOUR GLASS).

Wait a few minutes for the glass to cool off completely; this is to ensure that you do not burn yourself and to ensure that the glass does not crack with rapid cooling of temperate.

Once cooled, wipe away the soot with a cloth (preferably a microfiber cloth).

Repeat these steps until the lens no longer turns black easily; this is an indicator that there is no more or very little residue left on your mask.


You read correctly, saliva or spit.

Within a clinical practice journal of medicine, it is mentioned that saliva is even used as a way to prevent fog on flexible fibre-optic endoscopes.

Spit into the inside of the lens and coat around the mask with a clean finger and rinse off.

This is an easy method if you are already in the water and are having fogging issues.


I have only seen this done a few times, but it worked never-the-less.

Cut a potato and rub the inside of your mask with the inside of the potato using the juice to coat the lens.

Rinse once in fresh water and give it a shot.

The disadvantage of this is that the film from the juice is easily washed away in salt water and you will end up spitting into your mask anyways; however it does work and is worth a shot if you do not have any toothpaste.

Why do Snorkel Masks Produce fog?

Besides the scientific understanding that moisture accumulates when there is a difference of temperature between two sides of a surface like glass.

There are three basic reasons for this happening:

  • It’s a new snorkel mask
  • The mask is dirty
  • There is moisture getting inside while using it (likely the snorkel mask fits your face shape improperly)

It is a New Snorkel Mask

Unlike other new products, snorkel masks are not ready for use right after purchase.

There is a oil residue left over from the factory that promotes fog build up while in the water.

This needs to be removed before any reasonable use can occur.

The Snorkel Mask is Dirty

Oils left over from previous use can attract moisture quickly.

Therefore, cleaning every time before and after use will ensure this is not something you run into.

Moisture Getting Inside While In Use or Before

Moisture is what the fog inside your mask is.

Moisture can easily get inside your snorkel mask if you have facial hair.

Ensuring that the mask and your face is dry before using will prevent most of this.

Another reasoning is that your mask does not fit, is fitted improperly, or there is a leak/hole in the silicone skirt (which requires a new mask altogether).

This list will help ensure that you will not run into fog in your snorkeling or diving mask.

With several different uses people search for how to prevent fog in your snorkeling mask we will break down first time use (brand new masks), everyday use, and what can be done if your mask fogs up in the middle of your snorkel or dive session.

There are other techniques that can be used if it is a persisting issue even after following these steps.


There are many ways to go about preventing fog accumulating in your mask.

The quickest and most effective is the toothpaste method; one that I use every time I head out into the water.

Being sure to prepare your gear after every trip into the water and after will ensure that you will not run into anymore issues with fog on your lens.

[Sources and References]

L. Fraser, S. Gunasekaran, H. Cruickshank – Patient saliva: a useful anti-fog agent for the fibre-optic nasolaryngoscope

[Image Attribution and Licensing]

#1 Image by Couleur