How to prevent swimming goggles from fogging up

Is it possible to prevent or delay the formation of fog on swimming goggles or masks? Yes! Here are our tips and techniques on how to swim without fog.
Decathlon Ireland
September 20, 2023

Fogged up swimming goggles… We've all been there. It clouds our training and blurs the pleasure of swimming. Having to stop every few lengths to try to get rid of it; we've all searched for ways to make it a thing of the past.

So here we will be sharing our top tips on how to prevent or delay the formation of fog on your swimming goggles!



Your goggles fog up when you swim due to a rather simple physical phenomenon. The space between the lenses of your goggles and your eyes is airtight, the air contained in this space cannot escape. On one side, you have your eye and the skin on your face, which are damp and warm, and on the other, you have the lenses of your goggles, which are cold. The air in this space will therefore become more and more humid until it reaches saturation point. This saturation causes droplets to form, which settle on the coldest available surface, in this case, the lenses of your goggles. These water droplets form what we call fog, which blurs your vision when you swim. To be even clearer, it's the same principle as what happens in our bathrooms: when we take a hot shower with the door closed, the mirror fogs up!


Our first piece of advice is simply to choose swimming goggles with an anti-fog treatment. And we have technology to thank for that one! These days, most manufacturers of swimming goggles apply an anti-fog coating at the factory. Goggles of this type are no longer reserved only for professional swimmers or competitors; everyone can benefit from this technology, at very affordable prices.

Anti-fog treatments are not intended to prevent fog from forming. You may ask: what are they for then? It's simple, it's not about preventing fog from forming but rather preventing it from becoming inconvenient. So we make sure that the small droplets that make up the fog do not blur your vision. How does it work?

There are two types of anti-fog treatments: hydrophilic coatings and hydrophobic coatings. If your chemistry lessons feel like a distant memory after reading those words, let me give you a little refresher: a hydrophilic molecule likes water whereas a hydrophobic molecule repels it. A hydrophilic coating, once applied to the goggles, will therefore allow the multitude of droplets to come together, forming a sort of film of water on the lens. The droplets, instead of clouding your vision, will cluster together and leave your field of view completely clear. This is the type of coating applied to NABAIJI swimming goggles, for example. A hydrophobic coating prevents droplets from settling on the surface of the lens (a bit like water-repellent rainwear!).

Therefore, our first tip is of course to go for swimming goggles that already have an anti-fog treatment. When choosing your new equipment, read the product labels carefully to check that they already have an anti-fog treatment.

Looking after your goggles also helps them to fog up less quickly! The more damaged the surface of the lenses, the more they will fog up.

The golden rule if you want to take care of your swimming goggles and help them last longer is to store them in a protective case when they are not in use. This will prevent them from getting damaged or scratched as a result of coming into contact with other objects that could damage the lenses. In other words: don't chuck your goggles in your pool bag as soon as your session is over! ;)

Also, avoid rubbing the inside of your goggles with your fingers! By trying to remove the fog, you run the risk instead of damaging the coating already present on your goggles. The only exception to this rule are NABAIJI BFAST CLEAN & SWIM swimming goggles, where the anti-fog protection can be reactivated by gently rubbing the surface of the lenses.

Lastly, don't forget that by taking care of your swimming goggles, you won't need to replace the product as often, making them last longer!


Your swimming goggles have an anti-fog treatment, you take great care of them but, despite all that, after a certain number of hours of use, the fog returns… This is completely normal, it just means that the anti-fog treatment is starting to lose its effectiveness. So, rather than rushing to a store to buy a new pair, how about trying out some anti-fog techniques or products to extend the life of your current goggles?

The best techniques to stop your goggles from fogging up are without a doubt products specially designed for this purpose, such as an anti-fog reactivating marker or spray. As a second resort, I have a few old-fashioned tricks to share with you. These are, however, less effective and must be used with caution to avoid damaging your lenses. Above all, bear in mind that the coating on your lenses is fragile and that you must take care of it, even when you are trying to get rid of fog!

Anti-fog marker:


The purpose of an anti-fog marker is to reactivate the anti-fog treatment that is already present on your swimming goggles. It is therefore advisable to use it as soon as you notice that the anti-fog coating of your goggles is becoming less effective. Used in this way, the marker will help extend the life of your swimming goggles!

Here's how to use it properly:
- Start by applying the marker to dry lenses,
- Leave it to dry for at least one minute,
- Then immerse the goggles in water to spread out the product.
- Do not rub the lenses of your goggles during or after application as this could remove the freshly applied product and damage your lenses.

You may want to reapply the anti-fog reactivating marker to your lenses every two sessions or so, depending on how quickly the fog reappears. The product, once applied, will be effective for 1 to 2 hours, giving you time to complete your session with clarity. A single marker can be used to reactivate the anti-fog treatment at least 400 times!

Just to clarify, the anti-fog reactivating marker should not be used on new goggles as this could damage the new coating already present on your goggles. So wait until your goggles are showing signs of weakness before using it!


Anti-fog spray:

Anti-fog spray is specially formulated to prevent fog from forming in your swimming goggles and, as such, help you see clearly while you swim. It adds an anti-fog layer to the lenses of your goggles. It's very easy to use! Simply spray it on the inside of your goggles then thoroughly rinse them before use. Rinsing is essential to make sure that the product does not come into contact with your eyes. The bottle is often small in size and therefore easy to fit in your pool bag so that you can use it whenever you need. I must inform you that anti-fog spray, unlike the marker, should be used with care and sparingly. You don't need to use a lot of it for it to be effective! Overuse of the product could damage your eyes. So, stick to the recommended dose. ;)



So here I'm talking about liquid shampoo. Baby shampoo is even better! This technique is often thought of as a diver's trick. You only need one thing: your bottle of shampoo. You can perform this little exercise at home, before going to the pool, or in the changing rooms before your swim session. First, put some liquid shampoo on the inside of your goggles. Then, rub.…  But very gently! This is because the lenses of your goggles are fragile and you could damage them if you rub too hard. Under no circumstances should you use your fingernails or a towel to remove the shampoo. Then rinse your goggles with clean water (i.e. not in the pool!). I must stress the importance of rinsing your goggles thoroughly so that you don't end up with shampoo in your eyes. Because you don't want to avoid one problem just to replace it with another! ;) Once this is done, your goggles are ready!


Now here's a trick used by swimmers and divers! Granted, it's not the most hygienic… But it's tried and tested. You've all probably heard of swimmers spitting into their goggles… Well, it's not an old wives' tale. At least this alternative has the benefit of being natural and completely free! The technique is to put a little saliva on the lenses of your goggles, rub gently and then rinse.

Adding a layer of moisture to the lenses helps reduce the formation of fog. The aim is to stop the fog from settling on the surface of your lenses so that it slides off.


Yes, toothpaste can also help in the fight against fog! In reality, there's a whole host of everyday products that can also be used for swimming. All you need to do is apply a small layer of toothpaste to the lenses of your goggles, rub very gently with the pad of your finger, then rinse them with clean water. Once again, it is important to rinse thoroughly! Ending up with toothpaste in your eyes is not the best way to see more clearly. On the other hand, go gently when rubbing, you must press very lightly so as not to damage the lenses or the anti-fog treatment already present.

Next time you head to the pool, which technique will you choose to keep your goggles from fogging up? What is certain is that you now know all you need to know to be able to swim without this minor inconvenience!

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