How to Choose a Rash Guard: My Expert Tips for Snorkelers

Why Good Coverage Matters

Long sleeves are a must.

I’ve never understood short-sleeved rash guards—they leave your arms totally exposed, which defeats the purpose of full sun protection.

During our two-week snorkeling trip in French Polynesia, we were in the water every day, and long sleeves were a lifesaver.

If you rely solely on your favorite reef-safe sunscreen, you will likely feel your skin baking in little spots you missed. A long-sleeved rash guard? Problem solved.

Got a snorkeling trip coming up?

Don’t miss my post featuring my favorite sun shirts and swim leggings (yes, swim leggings—your legs need protection too!).

Why UPF50+ Matters

Most people are familiar with SPF for sunscreen, but UPF (Ultraviolet Protection Factor) measures a fabric’s ability to block UVA and UVB rays.

While all clothing provides some protection, not all fabrics are created equal. Light, loose weaves and natural fibers like cotton provide minimal coverage. For example, a white cotton T-shirt has a UPF rating of about 7—not great for long days in the sun.

I won’t bother with anything less than UPF 30+, and ideally, I go for 50+.

A rating of 50 blocks about 98% of harmful UV rays.

During our 11-site snorkel tour in St. John, I was grateful for that extra protection.

When you’re spending the day snorkeling, constantly reapplying sunscreen can be a hassle. And while sunscreen is important, studies show people often don’t apply enough or forget to reapply altogether.

A reliable UPF-rated rash guard offers peace of mind and keeps your skin protected without the extra effort.

Why Fabric Matters

Dense, synthetic fabrics like polyester and nylon offer the best UV protection.

These fabrics dry quickly, which is a lifesaver when you’re snorkeling multiple spots—like the time we explored 2-3 sites a day in Bonaire back-to-back.

Early in my snorkeling days, I made the rookie mistake of wearing lightweight shirts—and I paid for it with a painful sunburn. 

Lesson learned—polyester and nylon from here on out.

Why Color Matters

Don’t underestimate the power of a good color choice!

Darker or brighter shades absorb more UV rays, giving you better protection.

My Coolibar rash guard (in Baja Blue as seen above) has been my go-to for years, and it’s held up beautifully across multiple snorkeling trips.

Bonus: the vibrant colors make it easy for my husband to spot me in the water.

Why Fit Matters

A snug (but not skin-tight) — that’s the sweet spot.

Clothing that’s stretched too tightly can reduce UPF effectiveness.

But don’t go too loose, otherwise you’ll drag through the water.

I’m a big fan of Tuga rash guards—they’re fitted without feeling restrictive. I like to think of them as my “just right” Goldilocks fit.

A great rash guard isn’t just about sun protection—it’s about staying comfortable, confident, and worry-free so you can focus on those incredible underwater views.

And yes, you can find one that’s both functional and stylish.

After exploring some of the world’s most stunning snorkel spots—from the crystal-clear waters of Moorea to the colorful reefs in the Maldives—I’ve learned firsthand that the right rash guard can make a huge difference.

It’s saved my skin (literally) more times than I can count.

Choose one that fits well (not too snug and not too loose), offers solid UPF protection, and dries quickly, and you’ll be set for hours of carefree snorkeling.

Hope this guide helped!

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