You know that moment. You've clocked in at the pool, warmed up, and you're two lengths into your first 400m set when bam your goggles turn into frosted bathroom windows. You can barely see the black line, let alone the pace clock. You stop, wipe them with your thumb (which does nothing), and spend the rest of the session squinting through the blur or stopping every 100m to rinse them out.
Sound familiar?
I've been there more times than I care to admit. I swim with my club three to five times a week, and goggle fog has derailed more intervals than I'd like to count. The annoying part? You're not doing anything wrong. Fogging is just physics meeting wear-and-tear but the good news is, there are fixes that actually last beyond one session.
Let me walk you through why it happens and, more importantly, what you can do about it.
Why Do Swimming Goggles Fog Up?
Here's the short version: fog is condensation. When warm, moist air inside your goggles meets the cooler surface of the lens, tiny water droplets form and that's your fog.
As club swimmers, we create the perfect storm for this:
- Instant fog on the push-off: The second you dive in, your goggles are cooler than your face and breath. Boom condensation.
- Mid-set fogging: As your body heats up during hard intervals, the humidity inside the goggles rises. More warmth + more moisture = more fog.
- Fog creeping back after a few weeks: Even "anti-fog" goggles aren't magic. The factory coating wears down over time, especially if you've been touching the inside of the lenses or storing them incorrectly.
- Taking them on and off between sets: Every time you lift your goggles onto your forehead or pull them off to chat, you're letting in warm air and transferring oils from your skin and hair. This can contribute to fogging because it interferes with how evenly water spreads across the lens.
The science is simple, but the frustration is real. The trick is knowing how to work with your goggles, not against them.
How to stop swimming goggles fogging (the fixes that last)
Let's break this into two camps: what to do every time (to protect what you've got) and what to do when fog returns (to bring them back to life).
How to protect the anti-fog coating on goggles
Most decent goggles including all of Maru's training and racing lines come with an anti-fog coating applied at the factory. It's a thin hydrophilic layer that helps water spread evenly instead of beading into droplets. The problem? It's fragile.
Here's how to make it last:
Don't rub or wipe the inside lenses. I know it's tempting when you're mid-set and desperate to see, but your fingers (and towels) strip that coating faster than anything else. Even a gentle rub does damage over time.
Rinse gently after every swim. Use cool or fresh water, and let it flow over the lenses don't scrub. This washes away chlorine, sweat, and oils that degrade the coating.
Shake them dry, don't wipe. A quick flick gets rid of most of the water without touching the lens.
Store them properly. Use a case or pouch, and make sure the inside lenses aren't pressed against anything rough. I've seen too many good pairs of goggles scratched to death at the bottom of a kit bag.
Do this every session, and your anti-fog coating will last.
What is the best anti-fog for swimming goggles?
Eventually, even with perfect care, the factory coating fades. When that happens, you've got two solid options:
Use a proper goggle anti-fog spray or gel. These products are designed to refresh that hydrophilic layer. Apply a small amount to the inside lens, spread it gently with your fingertip, let it sit for a few seconds, then rinse lightly. Reapply every few swims or whenever you notice fog creeping back.
The baby shampoo method (DIY classic). This one's been passed down through generations of swimmers for a reason. Put a tiny drop of no-tears baby shampoo on each lens, smear it around gently, let it sit for 20–30 seconds, then rinse lightly with cool water. It works because baby shampoo contains mild surfactants that reduce surface tension and help prevent fogging. Just don't overdo the rinsing you want a thin film left behind.
A quick safety note: avoid harsh chemicals, household cleaners, or toothpaste. Toothpaste is abrasive and will scratch your lenses, which makes fogging worse, not better.
How to stop goggles fogging before you swim
Here's a quick trick I picked up years ago: before you put your goggles on, give them a quick dunk or rinse in the pool water. This brings the lens temperature closer to the water temperature and reduces that initial condensation shock when you dive in.
It's especially helpful in winter or if your pool runs cold. Takes five seconds, saves you a foggy first 200m.
Does spitting in goggles stop fogging? (myths vs facts)
"Spit works, right?"
Sort of. Saliva has mild surfactants (like baby shampoo), so it can reduce fogging in a pinch. But it's inconsistent, not particularly hygienic, and definitely not a long-term plan. If you're in the middle of a session and desperate, fine but it's not a substitute for proper care or re-treatment.
"Toothpaste cleans the lens and stops fog."
No. Toothpaste is an abrasive. It scratches the lens surface, which creates more texture for water droplets to cling to. You'll end up with worse fogging and a pair of goggles that look like they've been through a cheese grater.
"Scrubbing makes them clearer."
Opposite. Scrubbing destroys the anti-fog coating. The clearer you think you're making them, the foggier they'll be next time.
Best anti-fog swimming goggles for training (when it’s time to replace)
I've tested a fair few goggles over the years, and one thing I appreciate about Maru's range is that anti-fog coatings come standard across their adult training and racing lines. You're not paying extra for a feature that should just be there.
Here's where specific models shine if fogging (and the conditions that cause it) are your main headache:
- Outdoors or bright pools? The Groove Polarized Mirror Anti-Fog goggles are polarised and mirrored, which helps with glare while keeping fog at bay even when temperatures shift.
- Everyday club training with a reliable, comfortable seal? The Magna Anti-Fog or Swift Anti-Fog with UV protection goggles are solid all-rounders.
- Like a low-profile racing feel but still need anti-fog reliability mid-set? The Pulse Mirror or Sonic Mirror goggles offer that streamlined fit with mirrored lenses and anti-fog coatings that hold up through hard intervals.
These aren't magic. They'll still fog if you rub the lenses or don't rinse them. But if you follow the care steps above, they'll give you clear vision session after session.
Anti-fog goggle routine for every swim
Here's the habit that'll save you more frustration than anything else:
- Before you swim: Quick rinse or dunk in pool water to pre-condition the lenses.
- During your swim: Resist the urge to wipe or rub the inside lenses, even if they fog a bit.
- After you swim: Rinse gently with fresh water. Shake dry.
- Store them properly: Case or pouch, lenses protected.
- When fog returns: Re-treat with anti-fog spray or baby shampoo method.
That's it. Twenty seconds of habit, months of clear swimming.
Swimming goggles fogging FAQs
Why do my goggles fog up immediately when I dive in?
That's the temperature difference between your warm face and the cooler lens. Pre-conditioning your goggles with a quick dunk in the pool water before putting them on helps reduce this initial shock.
How long does the factory anti-fog coating last?
It varies, but with proper care, no rubbing, gentle rinsing and proper storage you can get several months out of it. Without care, it can wear off in weeks.
Can I use toothpaste to clean my goggles?
No. Toothpaste is abrasive and will scratch the lens, making fogging worse. Stick to gentle rinsing with water or a proper goggle cleaner.
Does baby shampoo really work as an anti-fog solution?
Yes. Baby shampoo contains mild surfactants that help prevent water droplets from beading up. Use a tiny amount, spread gently, let it sit briefly, and rinse lightly. It's a reliable DIY method used by swimmers for years.
Why do my goggles fog more during hard intervals?
As your body heats up and your breathing intensifies, you create more warmth and humidity inside the goggles. That warm, moist air hits the cooler lens surface and condenses into fog.
Do anti-fog sprays actually work?
Yes, when used correctly. They refresh the hydrophilic coating that prevents fogging. Apply a small amount, spread gently, let it sit, then rinse lightly. Reapply every few swims or as needed.
See You in the Pool
Goggle fog is one of those things that can make a good session feel like a slog but it doesn't have to. With a bit of care, the right re-treatment when needed, and goggles that are built to handle real training (like Maru's anti-fog range), you can spend less time squinting and more time hitting your splits.
And if all else fails? At least you know it's not you it's just physics.
Swim well,
Written by Alex Carter - club lap swimmer and poolside coach who’s tested more goggles than they can count.
