If you’re shopping for a new mask on places like Amazon and you look at the comment section (which you always should), you’re almost guaranteed to see people complaining about mask fog. 

They didn’t like this or that mask because of “fogging.” 

There are often contradictory reviews under the same mask both criticizing and lauding the mask for its fogging and lack thereof, respectively. 

The first reviewer gave the mask a one-star review because it just kept fogging, the second person a five-star review because it never fogged. 

The vast majority of the time, if you want to prevent your snorkel mask from fogging up, it has nothing to do with a particular mask itself. 

So long as you’re buying something from a reputable mask manufacturer that has a good quality tempered glass lens, YOU are the one who controls whether you end up with a foggy mask or not. 

I put together a review of the best snorkel masks for serious snorkelers that you can check out here if you like.

It includes different mask types, budgets and sizes for different snorkelers, all from respected dive gear manufacturers. 

With that said, here is how you prevent snorkel/scuba mask fog.

These three steps work with all masks, everywhere and basically all the time. They are the only three things you need to do to stop snorkel mask fogging. 

First off, what causes fog on a snorkeling mask?

Apologies if this is old news, but it bears a quick explanation because it helps the steps I detail below to make more sense. 

“Fog” is condensation, and condensation occurs when warm air hits a surface of a colder temperature. 

When the two different temperatures make contact, the warm air is no longer able to retain its moisture and that moisture is deposited onto the surface in the form of condensation.

When it comes to snorkeling masks, this is the small amount of air that escapes into your mask as you exhale through your nose and the air that is warmed inside your mask space by your face. 

Your body is almost always going to be warmer than the ocean temperature (even in the tropics) and, while your nose is blocked by the mask, small amounts of air can escape into the mask chamber. 

You aren’t going to be able to stop either of these things from happening and heating the air inside your mask, but what you can do is alter the physical surface of the glass so that it is less hospitable to condensation.

Step 1: Get rid of the safety coating on a new mask 

During the manufacturing process, the tempered glass of a brand new snorkel mask is coated with a thin layer of scratch protector–usually silicone. 

This silicone film is resistant to your standard defogging measures, so you do need to get rid of it before using the mask. 

The best way to do this is using the lighter trick. This is what your typical dive shop does and it is what I’ve seen work best.

The lighter trick 

This is probably the oldest of the “tricks”, and it has worked great for me.

It’s one of the most recommended snorkeling tips that I have passed on to people throughout the years. 

I’ve used it on several different masks from different manufacturers (Cressi, Phantom Aquatics, Scubapro) without issue. 

Basically, what you’re doing here, is holding a new snorkel mask upside down (with the skirt facing the ground), taking a lighter, and slowly moving the flame across the entire surface of the glass to burn away the material. 

The silicone coating will start to turn black, which you should then be able to easily wipe off with a soft cloth and some warm water.

Be prepared to do this a couple of times (or more). Often, you don’t get all of the protective coating off the first time around. 

A word of caution

I’ve never had this happen to me before, but there have been cases where new masks treated in this way have shattered upon contact with cold water. 

Tempered glass is designed to be tough (both hard and scratch-proof), which is why any serious snorkeler or scuba diver is going to have a tempered glass mask, never plastic lenses. 

BUT, you should be careful not to a) hold the flame too close to the glass or silicone and b) hold the flame in one spot too long. 

Tempered glass is tough, but it’s not indestructible, and if the flame makes contact with the glass for too long, you could weaken and warp it, which could make it more prone to cracking or shattering. 

What’s more, while the silicone rubber skirting on your mask can withstand extreme temperatures, it isn’t made to withstand them for long periods of time. 

Don’t be afraid to use the lighter trick, but do be careful. A mask burned too long is not a good idea. 

Step 2: lubricate the interior glass with a thin layer of natural baby shampoo before each snorkel/dive

If you’ve done the lighter trick properly (again, you might have to do it a couple of times), then a new snorkel mask should be much more responsive to something like baby shampoo before you hit the water. 

There are a ton of different substance recommendations out there when it comes to treating your mask pre-snorkel/dive–toothpaste, special anti fog solution, dish soap, and spit. I’ve used all of them and baby shampoo, IMO, is the most viscous and long-lasting. 

It is also the least caustic on your skin and eyes and, if you buy something organic, the best for the environment. 

A few drops spread across the entire interior surface of the glass with your index finger and washed out right before you get in the water is enough to keep your snorkel mask fog-free for the majority of your dive or snorkel session. 

Clarifying a couple of things

I thought I’d clarify a few things because I still see them pop up in comment sections and reviews from time to time. 

The first is that you only need to apply baby shampoo to the interior of the glass (not the exterior). Condensation doesn’t form on the exterior. 

The second is that you should apply the shampoo barrier to a dry mask (never wet)

The third is that you wash the soap out right before you snorkel or dive. That means once you arrive at the beach or just before jumping off the boat into the water. 

Of course, what this also means is that you are most likely going to be washing your snorkel mask out with seawater (or freshwater, if you’re in a river, lake, etc.). 

This is why you need to use an organic substance. You can get cheap, travel-sized bottles of all-natural baby shampoo that work just as well as Johnson and Johnson and will last you for a hundred+ dives/snorkel sessions. 

When snorkel mask fogging becomes inevitable

Snorkel masks fog. You might enjoy crystal-clear vision for a couple of hours, but almost every snorkeling adventure involves some fog. 

Even if you follow both of the steps outlined above and treat your mask properly, if you stay in the water long enough, you almost always find yourself with a foggy mask. 

The salt water will eventually get rid of the thin layer of shampoo (especially if you are clearing water from your mask every so often) and you will have to result to spit, constant mask flooding/clearing to regulate the temperature inside your mask or take a break to apply more shampoo. 

Step 3: Post-snorkel/dive care

The third and final step is to keep your snorkel mask as pristine as possible. 

Snorkel mask fogging happens because you haven’t removed the protective coating and created a condensation barrier with something like baby shampoo, but it’s also more likely if you have a grimy, scratched-up mask. 

At a bare minimum, you should be rinsing your mask off with warm, fresh water following each snorkel or dive. 

If you want to take it even further, you can prepare a very mild solution of dish soap and warm water and clean the inside and outside of the glass with a very soft brush or wash cloth. 

A thorough cleaning after each dive keeps your mask gets rid of salt water, oil, and residue left from the shampoo, and remove anything stuck to the lens that might scratch it over time–sand, salt, etc. 

Additional tips for fog free snorkeling

There are a couple of things you can do to prevent snorkel mask fogging that have nothing to do with how you treat your mask. 

The first: buy the right sized mask

A good way to stop even a treated mask from fogging is to get one that fits your face. 

A well-fitting mask lets in less water, which means less salt water comes into contact with and slowly washes away your shampoo fog barrier. 

Masks are usually made with small faces (i.e., ladies), larger faces (i.e., men’s) and children in mind. 

Read the comments and mask specs before buying anything–especially online, since you can’t try it on and don’t want to send it back. 

If you’re buying on Amazon, I like doing a quick “ctrl f” of the word “fit” or “size” in the comment section 

to see what previous buyers have to say. 

Not a guarantee of anything, but if you’re a woman looking for a mask for a smaller face, for example, and there are a lot of women in the comment section praising a mask’s fit, it’s a good sign. 

Shave your face

A smooth face is good anti fog. 

If you’re a guy with a beard and you like to snorkel/dive, you might have noticed a much better seal when you’re clean-shaven. 

This makes sense, as your facial hair stops the silicone skirt from creating a good seal with your face, letting in water. 

If you don’t want to shave, you can create a better seal between your facial hair (particularly around your mouth) by applying a thin layer of vaseline. I’ve found this usually stops leakage and an early fog problem. 

A foggy mask is up to you

If you get yourself a mask that fits well and is made of quality materials and if you do the things I’ve covered in this article, you’ll be good. 

• Flame trick
• Application of anti-condensation barrier (i.e., baby shampoo) before hitting the water
• After-water care

And, if you’re a guy, keep that beard trimmed. 

Cheers.