How To Defog Your Scuba Diving Mask | Tips & Tricks | Scuba Leeds UK

How To Defog Your Scuba Diving Mask

Knowing how to defog a scuba diving mask is one of the most useful things you can learn. A fogged up scuba diving or snorkelling mask is one of the most common preventable annoyances in scuba diving and snorkelling. No matter how fancy your dive mask is, how clear the glass, you still won't be able to see through it properly if it keeps fogging up. 

We've all been there - you gear up, put on your mask and start your descent, ready for an amazing dive with lots and lots to see. Only a few seconds into the dive, your mask fogs up, which means you're now having to add water and clear your mask every few minutes throughout the dive to rinse it out. It's not fun.

But it's not just our view that's being spoilt by the fog. Thinking about buddy communication, we mostly use our hands yes, but our eyes and expressions around the eyes also show a lot of what we're trying to say. And I'm not just referring to a smile, but also when there's an issue or a situation of panic, it's usually the eyes that give it away first. And you can't see those well on a buddy if their mask is fogged up.  

Therefore, we often get asked why fogging up happens and what we find to be the best ways to defog a scuba diving mask.



  1. Why do masks fog up
  2. Commercial Defogs
  3. Baby Shampoo
  4. Washing Up Liquid
  5. Toothpaste
  6. Potatoes
  7. Spit


Best Ways To Defog Your Scuba Mask

1. Why do masks fog up 

Fogging is essentially a build-up of condensation, which is water vapor present in the air in the gap of your mask. This happens because the mask lens is in constant contact with the water you are diving in, and this water is cooler than the air in your mask. The water vapor in the air inside your mask comes into contact with the glass of your mask and then cools. As it cools, it turns back into a liquid - this is called condensing. These tiny droplets hang on any imperfections or dirt in the glass, and is the fog that then blocks your view.

To prevent the mask from fogging up, we need to make the surface smooth so the water cannot hang on it. To achieve this, we need a slick, slimy, slippery product that causes the water to slide to the bottom of the mask, which is how the defogs on the list below works. 


2. Commercial Defogs

One of the most common, straight-forward and reliable ways to defog your mask is by using a commercial defog. 

There's several options available, from your standard diving defogs to defogs that work with normal glasses that fog up when wearing a facemask, to reef-friendly versions. Click here to check them out now.

They all come with instructions, but it's really no rocket science - drop or spray the solution, rub around the lens and rinse out. 


3. Baby Shampoo

Baby Shampoo is a popular option for defogging masks, and a very cost-effective one at that. Technically, any shampoo will do, however the baby shampoos come with no-tear magic, which is essential as I'm sure you can imagine.

Find a little reusable spray bottle, dilute some no-tear baby shampoo with some water inside the bottle and voilà, job done. 

You then simply spray your solution into your mask, rub and rinse. 


4. Washing Up Liquid

Same principle as with the baby shampoo - dilute, spray, rub, rinse.

I used lemon washing up liquid once and it made me sneeze all dive, I think it must have used pollen for the smell. You will also need to be careful if you need to rinse your mask, as any soap in the eye can really make them sore and it is really hard to rub your eyes with a scuba mask on.


5. Toothpaste

If you haven't done this before, toothpaste is the best way to prep your mask if it's brand-new and hasn't been dived before. It also won't do any harm to rub some before a dive day, however it shouldn't be your go-to solution for defogging on a dive site just before a dive. 

To prep your mask, rub the toothpaste on the inside of the mask, making sure the whole lense is covered. Rub around and then rinse gently with fresh water until the lens is clear and no toothpaste remains.

Make sure you rinse thoroughly, as any leftover toothpaste can make your eyes water really badly. It does make your mask smell minty fresh though!


6. Potatoes

A weird and random one, but if it works it works. Trialled and tested by members of our dive team as well as students recently during a PADI Reactivate session (they didn't just bring a potato to the pool, we asked them if they wanted to try it), it definitely works!

A slice of potato rubbed on the inside of a mask lens has been said to keep a mask from fogging, so why not experiment and try it for yourself?

Do you want to carry a stash of potatoes on the back of a dive boat? Maybe not. Is it cool and geeky knowledge knowing that it works? We think so! 


7. Spit

You probably already know that using spit for defogging a mask is the most well-known and widely-used method out there. And why wouldn't it be - it's always available, there when you need it, and best of all, free. 

However, since COVID-19 changed the world as we know it, spitting in masks has become a big no-no, for obvious reasons. As such, we would recommend you stick to one of the other methods from our list above - there's plenty of options, so you should never have to dive with a foggy mask anymore! 



What's your favourite way to defog your mask? Do you know of any other weird and wonderful ways that work? Let us know in the comment section below, we can't wait to hear it!

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