Brand-new dive masks fog. Not a little, a lot, and no defog seems to help. That’s not you and it’s not your defog. New lenses leave the factory with a thin film from manufacturing, and until it’s gone, condensation beads up on it no matter what you put on the glass. Here’s how to get rid of it before your first dive.
Quick answer
Scrub the inside and outside of the lens with a small amount of plain, non-gel, non-whitening toothpaste or a mask cleaner made for the job. Rub gently with a fingertip for a couple of minutes, rinse thoroughly with fresh water, and repeat two or three times. Then use defog as normal before every dive. Check your mask maker’s instructions first, especially if the lens is tinted, mirrored or coated.
Why new masks fog so badly
Fog is condensation: warm, humid air from your face meets a lens cooled by the water and forms tiny droplets. Defog works by leaving a film that lets those droplets spread into a clear sheet. On a new mask, the factory film on the glass repels water, so the droplets bead up anyway and the defog can’t do its job.
Method 1: Toothpaste (the classic)
- Pick the right toothpaste. Plain white paste. Avoid gels, whitening formulas and anything with visible grit or crystals, which can scratch.
- Apply to a dry lens. A pea-sized amount on the inside of the lens, and another on the outside.
- Rub gently. Use a fingertip in small circles for two or three minutes, covering the whole lens edge to edge. Go easy near the skirt.
- Rinse thoroughly with fresh water until no paste is left in the corners or along the frame.
- Repeat two or three times. Many divers leave the paste on overnight before the final scrub.
Method 2: A dedicated mask scrub
Several dive brands make a pre-cleaner for new masks. It does the same job as toothpaste with less guesswork about abrasives. Follow the directions on the bottle.
What about burning the lens with a lighter?
You’ll see divers “burn” a new mask by running a lighter flame over the inside of the glass until it blackens, then wiping off the soot. It can work on tempered glass, but it’s easy to get wrong. The flame can melt or discolor the silicone skirt, damage lens coatings, or crack the glass if you hold it in one spot. Never try it on a plastic lens. Some mask makers specifically say not to. I don’t teach it to students, and I don’t recommend it. Toothpaste does the job without the risk.
How to tell when the film is gone
After the final rinse and dry, breathe on the inside of the lens. If the fog spreads into an even sheet and clears quickly, you’re there. If it forms blotchy patches that cling to some areas, those spots still have film. Scrub them again.
Tinted, mirrored and coated lenses
Some lenses have coatings for color correction, glare or UV. Abrasive scrubbing can damage them. If your mask has a coated lens, use the cleaning method the manufacturer recommends, and skip toothpaste and flame.
After prep: defog before every dive
Prep is a one-time job. Defog is every dive.
- Start with a clean, dry lens.
- Spray 2–3 pumps of defog on the inside of the lens.
- Wait 30–60 seconds so the film can set.
- Dip once, shake gently, and put it on. Don’t touch the inside of the lens.
If it still fogs after prep, see why your dive mask keeps fogging. For a comparison of defog options, see my instructor’s guide to the best scuba mask defog.
What I use
Defrogger is a spray with two ingredients: purified water and one plant-based cleanser made from coconut and sugar. No alcohol, sulfates, fragrance or dyes. It’s safe on tempered glass lenses and silicone skirts, and a 4 oz bottle lasts about 100 dives.
By Scott Fontecchio, PADI Master Scuba Diver Trainer and SSI Master Instructor with 40+ years and 5,000+ dives, and the maker of Defrogger. More about Scott.