How to Stop Snorkel & Scuba Mask Fogging+ Best Anti-fogs

Mask fogging is probably one of the most maddening things that can happen while you’re enjoying a snorkeling trip. Just picture this scene:

You’re sitting in a boat waiting for the go ahead to jump in. The guide has told you all about the wonderful things you’ll be able to see below the surface of the water. You’ll all ready to go. Mask on, snorkel in, fins on.

You put your face in the water, start swimming, and you can see the beautiful coral and colorful fish below you. But a few seconds in… your mask fogs up.

You take it off, rinse it, put it back on again. It’s fine for another few seconds but then it fogs again!

Here is how to make sure you’re never affected by the dreaded foggy mask syndrome again.

Causes: Why do Masks Fog?

It’s simple if you think about it. What happens when you take a cold bottle of water out of the fridge and leave it on the side? Soon enough it’ll be sitting in a puddle of water. Where did this water come from? It’s condensation from the differing temperatures inside and outside the bottle.

It’s similar to what happens to a mask when we go diving or snorkeling. The water outside the mask is a different temperature to the air inside the mask, next to our face.

This is why we can rinse a mask and it’ll be fine again for a few minutes, because we’re evening out the difference in temperature

But before long the condensation starts to build up again and the mask becomes foggy. So how is it possible to stop this annoying occurrence?

When water vapor collects on the inside of your mask, in order for the tiny droplets to stay on the lens and not run down to the bottom of the mask they must have something to attach themselves to.

This could be miniscule impurities in the glass or it could be specks of dirt and sand. The level of fogginess also depends on how humid it is inside the mask, and what the temperature is like outside the mask.

Foggy mask
Mask with fog

Keeping your mask as clean as possible is important to not only prevent fogging but also improve your snorkeling experience. This includes not wearing any sunscreen or lotion which could easily be transferred to your mask in the water.

Using some kind of surfactant such as an anti-fog spray, washing up liquid, or spit, helps to smooth out the tiny droplets so that they form an even layer of moisture on the lens. This is much easier to see through than the tiny individual droplets all over which give that fogged up result.

How to Defog a Brand-new Mask

Before we go into the different methods of defogging your mask, let’s talk about the first one-off treatment required for lucky owners of a brand-new snorkeling mask.

Most masks are made with tempered glass and silicone, however there are also some plastic or polycarbonate ones, as well as those with anti-fog properties

If your mask is polycarbonate you need to be extremely careful when cleaning it, as these types of masks can scratch very easily. If you have bought an anti-fog mask then you can skip the following steps completely.

Masks that are made with tempered glass leave the factory coating with a thin protective layer. You’ll need to get rid of this to have any hope of being able to see underwater.

Step One (Only for masks made with tempered glass)

Find somewhere where there’s no breeze and hold your mask carefully with one hand. Use the other to carefully burn the inside of each lens with a lighter. Be careful not to burn either yourself or the surrounding silicon material when you are doing this.

It’s easiest if you hold the mask above you and face down so that the flame is pointing straight and you can see what you’re doing. Burn the entire inside surface of each lens so that the glass turns black. Then put it to one side for a few minutes to cool down.

If this process seems scary to you and you’re worried about harming your lovely new mask, ask a professional to help you. Try your local dive center or the shop where you bought the mask. The staff will no doubt be happy to help you remove the factory layer.

Step Two (Skip straight to this step for polycarbonate masks)

The next part of the process includes toothpaste and an old soft toothbrush, or your fingernails. The reason we use toothpaste is because of the slightly gritty texture which will gently remove the protective layer from the lens.

Squirt a pea-sized amount of toothpaste on each lens and gently scrub. If you’ve burnt your mask you’ll end up with a smoky black mixture. Leave your mask to one side for an hour or two and then rinse with water, using the toothbrush again or your nails to clean the surface until it’s completely clear again.

Remember that for polycarbonate masks you’ll need to be extremely careful not to scratch the surface of the lens.

Even after the initial burn and toothpaste treatment, many divers continue to use toothpaste now and then to give their mask a good deep clean. You’ll be surprised how quickly yucky stuff can build up inside!

defogged mask
Clean, free of fog mask

Day-to-Day Defogging

To get the most out of your mask and out of your snorkeling adventures you’ll want to defog your mask before each and every time you use it. There are many different products on the market you can buy to help with this, as well as home-made solutions, and of course the cheapest option, saliva.

Commercial Defogger

Go into any dive center and you’re likely to see at least one, if not several, commercial mask defoggers. They’re usually small bottles, either a spray or sometimes a gel-like substance where you squeeze a blob into each lens.

Use your clean dry fingers to rub the substance all over the lens and then just before you put on the mask, rinse it thoroughly in fresh or salt water, but don’t rub the glass with your fingers or you’ll have to do it again.

Anti-fog Sprays and Gels

McNett, which offers both a gel and spray version (Sea Gold and Sea Drops), is a popular brand among divers, as well as Madwave, Cressi, and Seac anti-fog solutions.

Anti-fog Film

Tusa makes a reusable film that you can apply to the lens of your mask before diving. These work well but can be a little fiddly to use.

Anti-fog Sticks

A Spetten product, de-fogging sticks which work just like a spray or gel but instead you rub the stick over the lens and then rinse as usual.

Washing Liquid + Water

Many dive and snorkel boats will have a big bottle of greenish looking liquid they’ll spray on your mask for you before you get in.

There’s no big mystery as to what this substance is – it’s usually simply washing up liquid mixed with water.

The method is exactly the same; rub the substance all over the lens and then rinse. You can make your own version using washing up liquid or other similar substances.

Baby Shampoo

Another homemade solution which is popular with divers is baby shampoo. It’s easy on the eyes, and is also usually hypo-allergenic and biodegradable.

Mix it with water in a small spray bottle and keep in your mask box so you always have it handy. You can use it the same way as other de-foggers; rub a small amount all over the lens and then rinse.


As mentioned before, toothpaste can also be used as a day to day defogger, although you’ll need a lot smaller quantity than for removing the factory protective sheen. This can make eyes water and sting just like washing up liquid so care should be taken to rinse thoroughly.


Most dive professionals who are eco-friendly and dive every day don’t bother with any of the methods above.

It might not be the most glamorous way to make sure your mask doesn’t fog but it means no chemicals going into the ocean or your eyes.

It’s also far cheaper, and it works just as well. So, don’t be shy. Spit a decent glob of saliva into your mask and swill it around with your fingers before rinsing. Getting used to this method will also mean that you can defog while snorkeling if you’ve forgotten beforehand or didn’t do a good enough job.

Anti-fog Masks

Many of the full-face snorkel masks claim to be anti-fog due to the way the ventilation works.

However, the small print will tell you that in extreme temperature differences further measures will probably need to be taken, that is, one of the options listed above. It works by having a layer of surfactant applied to the glass in the factory.

However, this layer won’t last forever and you’ll soon be back to using toothpaste, spit, and other methods. Not many masks offer this feature. It’s more important to find one that fits well than one with gimmicky features such as claiming to be anti-fog.


Which Solution Works Best?

Most snorkelers and divers will try many different methods before deciding on the one that works for them best. It really is a personal preference.

Make sure your mask is as clean and dry as possible before you apply anything to it.

Also make sure you’re not wearing sunscreen as the grease can attract dirt and therefore increase the chance of mask fogging.

Snorkeling Masks & Snorkels

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