During a dive, fogging can be very annoying and can actually make you miss a dive. Would not you be upset to hear your partner claiming he or she has seen a manta ray while you were in the dark ? To avoid this, follow the guide:
What should you do to avoid fogging on a new mask ?
- During 24 hours, dip your mask into a mix of water and dishwashing liquid. Then rinse with warm water.
- Apply toothpaste during a full night and then rinse with hot water.
- Gently heat the inside of the glasses with a lighter ensuring, of course, not to damage the mask.
How to avoid fogging just before diving ?
Anticipate! Before each dive, on the dry and clean lenses of the mask, you can apply it is of course possible to combine them:
- Some anti-fog product in liquid, gel or spray.
- Apply saliva on the mask’s lenses when it is dry.
- Liquid dishwashing.
- Toothpaste

What to do in case of fogging during a dive ?
First tip is pretty simple and accessible to certified diver. After making sure of good buoyancy, let some sea water fill your mask and then, empty it by expelling with your nose. This will solve your problem this time but fog may quickly return.
Second tip, if you have any doubt or problem about one of your masks, you should take with you a second spare mask and store it neatly in a pocket of your BCD. If fogging constantly reappears and exasperates you, just change mask.
Final tip is only recommended for highly experienced divers. After stabilizing your buoyancy, you can remove your mask and lick the lense of your mask. Repeat if you think you did not covered the entire surface. Once completed, you can put your mask on and the fog should not appear again during your dive. Avoid exhaling through the nose should also prevents fogging .
What is fog ?
Fogging is the result of condensation of water vapor on a cold surface with respect to humid environment. In a mask, exhaled air from the diver or the air, in contact with the skin, is hot and humid while the lenses of the mask are directly in contact with the cold water. The conditions are really favorable for the water vapor suspended in the condensed air in the mask to create mist on the glass .
The passage of water from gas to liquid, appears under the from of tiny droplets which are deposited on the mask glass. Employing an anti-fog product, saliva or other tricks see below allows the creation of a uniform film of water impermeable to droplets.