Ask any dive professional what the most annoying piece of dive gear is, and you’ll likely hear one answer: a foggy mask. There’s nothing more frustrating than descending into clear, beautiful water—only to find your visibility ruined by a mask you can’t see through. Everyone has their go-to fix, from burning it with fire to spending big on defog solutions. But let me walk you through the method that consistently works best for me and other dive pros I know. Why New Masks Fog So Much New scuba masks come with a thin coating on the inside of the lenses from the manufacturing process. This film makes them especially prone to fogging until it’s removed. If you skip the prep, no amount of spit or baby shampoo will save your vision underwater. The Fire Method – Popular But Not Perfect Yes, using a lighter to burn the inside of your mask is a thing—and it can work. Carefully passing a flame across the inside of the glass burns off the layer. The problem? You need to do it several times to be fully effective, and if you’re not careful, you can damage the silicone skirt or leave soot on the lens. It’s fast, but not always thorough. The Toothpaste Trick – Dive Pro Approved My preferred method? Good old-fashioned toothpaste. Here’s how I do it: Use non-gel, non-whitening toothpaste—just a plain, mildly abrasive kind. The cheapest Colgate one works great Apply a thin layer to the inside of the mask and let it sit as long as possible. Leave it overnight or even longer for best results. Better yet—pop the mask in the fridge while the toothpaste is on. This helps harden the paste, so when you gently rub it off, it takes a thin layer of that coating with it. Make sure you let the mask come back to ambient temperature before you use it. If you jump straight in with a fridge-cold mask you’re going to have a very foggy dive. After a couple of these overnight sessions, most of the factory coating should be gone—and you’ll notice a huge drop in fogging. Baby Shampoo – Great for Pre-Dive, But Temporary For regular dives, a drop of baby shampoo mixed with water works well as a pre-dive defogger. It’s gentle, effective, and reef-safe. Just remember—it only lasts as long as it stays on the glass. If you flood or clear your mask a few times, the effect fades fast. Pro tip: After a dive, add a little baby shampoo to your mask and leave it on until the next dive. Just give it a quick rinse and you’re ready to go. It’s a great habit that keeps the mask prepped without extra effort. Don’t Soak Your Mask in Water A common mistake: leaving your mask soaking in a rinse bucket or tub. The water is often cooler than the ocean, and that difference in temperature can cause instant condensation when you jump in. Instead, store your mask dry or with just a small rinse and air-dry between dives. Spit Still Works If you’re in a pinch, the classic spit-and-dunk method still does the job—especially if your mask is already well-prepped. Just give it a quick rub and a rinse in seawater right before jumping in. Don’t Over-Rub Your Defog Whether you’re using baby shampoo, commercial defog, or even spit, don’t fully rub it in like you’re cleaning a window. Just spread it around gently, then rinse it a couple of times max. Leaving a thin layer is key—that’s what actually stops the fog from forming. In Summary – A Fog-Free Mask Starts Before the Dive A foggy mask can ruin a dive—but with the right prep, it’s totally avoidable. Here’s your quick checklist: Toothpaste overnight (refrigerated is even better) Avoid soaking in cool water between dives Use baby shampoo pre- and post-dive for maintenance Spit and seawater as a backup method Don’t over-rinse your defog solution At Phoenix Divers Koh Tao, we make sure every student and fun diver gets a clear view of the underwater world—and it starts with a fog-free mask. Trust me, it’s worth the effort. See you underwater!