How to Choose and Fit a Snorkel or Dive Mask (Pro Instructor Tips)
If your snorkel or dive mask keeps leaking, fogging up, or making you feel claustrophobic — you’re not alone.
As A professional scuba instructor (PADI MSDT & SSI OWSI), I’ve seen hundreds of students struggle with masks during their first ocean experience. The good news? Most mask problems are easy to fix with a few simple techniques.
In this guide, I’ll walk you through how to:
Fit a snorkel or dive mask properly Stop leaks (even with facial hair!) Prevent fogging Understand strap positioning Decide between full-face vs traditional masks
Whether you’re snorkelling for the first time or preparing for your open water course, these tips will make your time in the water way more comfortable — and way more fun.
Full Face Mask vs Traditional Dive Mask — Which is Better?
Full-face masks look appealing for beginners…
But we don’t recommend them for the BEST experience, and here’s why:
| Full-Face Mask | Traditional Mask |
|---|---|
| Easy breathing through nose or mouth | Requires mouth breathing only |
| Can feel safer for nervous first-timers | Best for freediving + learning real skills for progress to scuba diving |
| Limited sizing (S/M/L) = poor fit | Many sizes & styles = better seal |
| Harder to clear if flooded | Easy to clear water |
Instructor takeaway:
Most guests who try both choose a traditional mask once they’re taught how to wear it properly — and feel way less claustrophobic.
Step 1: Proper Mask Fit Test
Place the mask on your face without using the strap
Remove hair from the mask skirt (the soft rubber edge around the edge of the mask) — smooth seal everywhere
Gently inhale through your nose and hold your breath
Let go of the mask
If the mask sticks to your face without falling, the fit is correct. If it falls off it means it’s got a leak and likely too big of ill-fitting, try a different size or style until you get one that creates a full vacuum when you inhale.
Pro Tip: If you have a moustache, apply Vaseline to the moustache line or if it’s stubble, try a clean shave for a better seal.
Step 2: Don’t Overtighten the Strap
If your mask is leaving marks like you’ve just finished wrestling an octopus — it’s too tight.
A properly fitted mask needs very little pressure.
In water, the gentle upward force naturally seals it.
Over-tightening can actually cause:
Seal warping Mask leaks Face pressure headaches “Mask face” indent lines Strap misalignment
Step 3: Strap Position
This is a big one most beginners get wrong.
Correct strap placement:
On the crown of your head Above the ears Not too high or too low
Wrong strap position = mask will slide, leak, and push snorkel underwater.
If your snorkel suddenly starts letting in water — your strap probably shifted.
Tip for long hair: Tie it back firmly so the strap doesn’t slip.
Step 4: Why Your Mask Leaks During Snorkeling
Even if you fitted it perfectly at the beach, once your hair loosens in the water, the strap moves slightly, the seal breaks, and suddenly — leaks and saltwater moustaches.
Solution: Re-adjust strap mid-snorkel Avoid over-tightening Smooth hair away from mask skirt
Anti-Fogging: How to Stop Mask Fog
New masks need prep.
Best method:
Use white toothpaste (non-gel)
Scrub the inside of the lens (with your finger or a medium/soft toothbrush)
Leave overnight
Rinse before use
On snorkel or dive day — use proper mask defog or baby shampoo
Rinse fully but gently (don’t rub with fingers)
Never use harsh abrasive cleaners on tempered glass masks unless trained.
Final Tips from Your Dive Pros
Practice calm, slow breathing Rinse mask with fresh water post-use Avoid touching inside of the lens Store away from sunlight Buy a mask that fits your face, not just looks “cute in photos”
Need more dive guidance?
We’re Aaron & Cassie — full-time ocean creators & professional dive instructors.
We share real, honest insight into diving in Asia and beyond.
YouTube: Aaron & Cassie
Instagram: @aaronandcassie
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