Nothing spoils a reef dive faster than a gray haze across your lens just as a turtle swims by. Learning how to stop mask fogging takes a few minutes on land and a few habits in the water, and it works the same for scuba diving and snorkeling.
This guide is for new divers, snorkelers and anyone who just bought a first mask. It follows the advice PADI publishes on its blog, step by step: why masks fog, how to prepare a new one, which defog to use, why fit matters and how to clear a mask underwater.
Wondering how to stop mask fogging before your next dive?
Quick answer: Clean a new mask’s lenses with non-whitening toothpaste and rinse. Before each dive, coat the inside with a commercial defog, diluted baby shampoo or spit, swish and rinse once. PADI also advises not touching the inside of the lens, breathing through your mouth and wearing a mask that fits, so less water gets in.
Why dive masks fog up
Fog is condensation: tiny droplets forming on the inside of a cool lens. PADI calls it a common problem for all divers, not a sign that you are doing something badly. Knowing the causes is most of the cure.
The PADI blog points to two habits in particular. Exhaling through your nose is a common cause, because it puts warm, moist breath straight into the mask. Water getting into the mask is the other, since that moisture promotes the condensation you see as fog.
- Breath in the mask: exhaling through the nose adds moisture.
- Water in the mask: a leak or flood leaves droplets behind.
- Oily fingers: PADI notes that oils from your hands can cancel out a defog product.
Preparing a new mask before its first dive
A brand-new mask is often the worst for fogging, which is why divers talk about the “new mask burn off”. PADI’s recommendation is gentler than burning anything: clean the lenses with non-whitening toothpaste, which it says is a great way to reduce fog, especially on brand-new masks. Specialized mask cleaners exist, but PADI presents toothpaste as an inexpensive alternative.
- Put a little non-whitening toothpaste on a soft toothbrush or on a finger you have just washed, so skin oils do not end up on the glass.
- Spread it over the inside of the lenses.
- Rinse the mask well without touching the glass.
- Test it by breathing into the mask. If it still fogs, repeat once or twice, as PADI suggests.
Do this at home before your trip, not on the boat. A new mask that has never been cleaned will often fog no matter which defog you use on the day.
How to stop mask fogging: three defog options compared
Once the mask is clean, you need anti fog for the dive mask before every dive. The PADI blog’s tips for preventing mask fog describe three options, and all of them work the same basic way: coat the inside of the lens, swish, rinse once.
| Defog option | How PADI says to use it | Worth knowing |
|---|---|---|
| Commercial defog spray or serum | Coat the lenses, swish, then rinse once in fresh or salt water | PADI says one application may last several dives |
| Baby shampoo | Dilute a few drops in water in a spray bottle and use it like commercial defog | PADI likes it because it is gentle, biodegradable and needs very little product |
| Spit | Spit on the lens, swish and rinse | Free, and PADI says many divers find it works better than products they buy |
Whichever you choose, the rule after applying it is the same: keep your fingers off the inside of the lens. PADI suggests a defog you can swish rather than spread by hand for exactly this reason.
Habits that keep fog away
- Breathe through your mouth: PADI admits this takes some getting used to, especially for snorkelers.
- Do not touch the inside: after rinsing, leave the lens alone.
- Start dry: PADI’s ideal is a mask put on dry skin that stays dry for the whole dive.
If you are new to the surface side of things, our snorkeling tips for beginners cover breathing through a snorkel and staying relaxed, which helps with the mouth breathing habit.
Mask fit: fewer leaks, less fog
PADI links fit and fog directly. A mask that fits poorly floods often, flooding means more clearing through your nose, and both add the moisture that fogs the lens. PADI accepts that some water always gets in, so the goal is simply to keep it to a minimum.
- Keep hair out from under the skirt, since trapped hair breaks the seal.
- Wear the strap snug, not tight, so the skirt rests evenly on your face.
- If you wear glasses or contacts, read our guide to scuba diving with glasses or contact lenses before you choose a mask.
If you do not own a mask yet, our homepage rental list includes a mask, snorkel and fin set. Rates are on our Water Sports page with current course prices. A wetsuit is the other piece of comfort gear to think about, and our guide to wetsuit thickness for warm water diving explains what to pack.
Clearing a fogged or flooded mask underwater
Sometimes fog creeps in anyway. The fix is to let a little water in, swish it across the lens and clear it out. That is the standard mask clearing skill, and PADI’s how to clear your mask guide breaks it into short steps.
- Let the mask fill slowly. Close your eyes if you wear contact lenses.
- Press the top of the mask frame with your index fingers to seal it.
- Look up and exhale through your nose.
- If water remains, exhale again and check the seal for trapped hair.
Practice it in shallow water until it feels routine. A diver who can calmly clear a mask treats fog as a small chore, not a reason to end the dive. If you are starting from scratch, our guide to learning to dive on Ambergris Caye explains the courses where you build these skills.
Learning with Elbert
White Sands Dive Shop is a 5 Star PADI Dive Facility on the beach in San Pedro, owned and operated by Elbert Greer, PADI IDC Staff Instructor. We offer daily diving, SCUBA instruction and snorkeling for new and experienced divers.
One student, Vivake K. Bhalla, wrote: “Elbert Greer was an outstanding instructor with a lot of experience and useful tips.” You can read more in our letters from students Elbert has taught.
How to stop mask fogging: your questions answered
Why does my new mask fog so badly?
New masks are often the worst. PADI recommends cleaning the inside of the lenses with non-whitening toothpaste, rinsing without touching the glass, and repeating once or twice if the mask still fogs.
Does spit really work as mask defog?
Yes. PADI says spit is free and many divers find it works better than products they buy. Spit on the lens, swish it around and rinse once.
Can I use baby shampoo to defog my mask?
PADI suggests diluting a few drops of baby shampoo in water in a spray bottle and using it like a commercial defog. It notes baby shampoo is gentle, biodegradable and needs very little product.
What do I do if my mask fogs during a dive?
Let a little water into the mask, swish it across the lens, then seal the top of the frame with your fingers, look up and exhale through your nose to clear it.
Does breathing through my nose cause fog?
PADI says exhaling through your nose is a common cause of mask fog. Breathing through your mouth takes practice but helps keep the lens clear.
Questions before your dive trip?
Not sure whether to bring your own mask or rent one when you arrive? Email Elbert at elbertgreer@fastmail.fm or phone 011 (501) 226 2405. Tell us your dates and experience, and we will help you plan your dives and snorkel trips.