Don’t Fear the Fog: How to Keep Your Dive Mask from Fogging

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A mask that won’t stop fogging is an annoyance nearly every snorkeler or diver has gone through, and can mean the difference between an incredible dive and a terrible one. Visibility range? Zero, if your mask is fogging.

Your mask is your window to the underwater world. Nobody wants to stop their dive every few minutes for a wipe-down or purge.

Masks typically fog because the heat or sweat from our bodies causes moisture to evaporate and condense onto the lens. The condensation is made from microscopic water droplets that are nearly impossible to see through. When you apply a defogger (surfactant) to the lens, you are creating an area where the droplets can join and form one thin layer of moisture instead of a surface of thousands of tiny drops.

Before you Dive

If you’ve just purchased a new scuba, snorkeling, or freediving mask, you can prep the mask to ensure it doesn’t fog in the future.

Most freediving, spearfishing, snorkeling, and scuba diving masks are made with tempered glass lenses. These lenses typically have a thin layer of manufacturing film on them when you buy the mask, usually to protect it from getting scratched while in production.

Burn your mask

Don’t start running around with a blow torch lighting masks on fire. For this step, take a lighter and burn the manufacturing film off the lens. Hold the lighter close to the inside of the glass and watch as the lens turns black. You will see the film burn away. Take care not to bring the flame too close to the silicone – or else you will probably warp/melt it. We don’t want our masks looking like they were crafted by Salvador Dali.

Before you do this step, check with the manufacturer to see if they advise against burning the mask lens. Some mask manufacturers suggest that their specific film be kept on. Prescription masks or masks with glued-on bifocal lenses should not be burned.  Do not burn plastic lenses. The film they come with is likely intentional and burning plastic lenses will obviously damage the mask.

If you are even slightly hesitant to use this step, just use the toothpaste method.

Rub the mask lenses with toothpaste

The toothpaste method is a favorite among divers, who swear it’s the cure-all to defogging a dive mask. The toothpaste should be the typical, somewhat gritty kind. Rub the toothpaste into the mask until the burn marks can be wiped away. Add a little more toothpaste to each lens, until both lenses are covered in a semi-transparent paste. You can even use an old toothbrush to really get every part of the surface – especially the edges, where the lighter likely missed.

Leave the mask to dry for a few hours before rinsing it with tap water and wiping the toothpaste residue away.

Don’t use harsh or abrasive scrubbing agents. Toothpaste will work most times, and anything harsh can damage the mask silicone – or worse, your eyes.

Should you use mask defogger?

With all the unnatural chemicals harming sea life and coral reefs, why not use the best defogger you’ll always have on hand? Spit into each lens and spread the spit around with your fingers. Don’t be embarrassed – nearly every diver does it.

If you have a dry mouth, you can always ask someone to spit in your mask for you. (Insert obligatory, “just kidding” here.)

To defog your mask using the resource that mother nature gave us, put a tiny bit of spit onto the lenses and rub it in with your finger. We’re not talking about hawking a loogie into your mask with everyone watching. Don’t be feral. The most effective way of using this method if spitting into a dry mask, rinsing it with water, and then putting the mask on – all right before you dive. Remember the golden rule of spitting in your mask: Don’t be feral. This also means not rinsing your mask in the communal dive bucket.

If you absolutely must use a mask defogger, consider buying one that won’t harm marine life. Stream2Sea makes a reef-safe mask defogger. Some people also use baby shampoo or soap as a defogger – the likely product that’s passed around on your dive boat.

Don’t touch the lens after you’ve put on the defogger.

Why is my mask still fogging?

If you’ve done all the steps above and your mask is still fogging, here are a few things you can try.

1. Do a full facial immersion. Dunk your head into the water to cool your skin down. Thanks to the mammalian dive reflex, this also tends to calm the body and slow down your heart rate – a strategy that’s essential for longer dives and peaceful snorkel sessions.

2. Keep your mask on your face. Handling your mask after you’ve applied defogger causes temperature changes within the mask and can lead to fogging. Moving it to your forehead often brings the lenses closer to the face and causes the mask to fog.

3. Dry your mask, defog it, then rinse it. If you can, apply defogger (spit) into a dry mask rather than a wet one. Even wiping it off with a towel or t-shirt beforehand will help. Then, when you are ready to dive, dunk the mask in the water, drain it, and put it on immediately.

4. Don’t exhale through your nose during your dive (unless you are equalizing the mask). If you constantly exhale into the mask, you’ll be warming the area between your skin and the lens.