Quick answer: UPF 30 blocks about 96.7% of UV radiation, while UPF 50 blocks about 98%. For long days and open-water exposure, UPF 50 or 50+ is the stronger default; always check the rating stated on the individual product.
If you've stood in front of a rack of fishing shirts wondering whether it's worth paying more for "UPF 50+" over a plain UPF 30 tag, here's the short answer: UPF 30 lets roughly 65% more UV radiation reach your skin than UPF 50 does. That sounds like a small gap on paper, but on the water — where sun exposure is constant and reflective off the surface — it adds up fast.
What UPF Actually Measures
UPF stands for Ultraviolet Protection Factor. Unlike SPF (which only blocks UVB rays unless labeled "broad spectrum"), UPF fabric ratings account for both UVA and UVB radiation — the two types of rays responsible for sunburn, premature skin aging, and long-term skin damage.
The math behind the rating is simple: divide 100 by the UPF number to get the percentage of UV that gets through the fabric.
- UPF 30 blocks 96.7% of UV rays — about 3.3% still reaches your skin
- UPF 50 blocks 98% of UV rays — about 2% still reaches your skin
- UPF 50+ blocks more than 98%, sometimes up to 99%
The Skin Cancer Foundation only awards its Seal of Recommendation to fabrics rated UPF 50 or higher — UPF 30 doesn't meet that bar, even though it's still labeled "very good" protection.
UPF 30 vs. UPF 50+: Which One Do You Actually Need?
UPF 30 makes sense if: you're fishing for an hour or two in the early morning or evening, fish mostly in shaded spots (docks, tree-lined banks), or layer a shirt over sunscreen as backup protection rather than your primary defense.
UPF 50+ is the better call if: you're on the water for full-day trips, fish in open water with strong sun reflection, have fair skin or a personal/family history of skin cancer, or you fish tournaments where you can't just head back inside when the sun gets intense. If any of that sounds like you, it's worth defaulting to 50+ every time — the cost difference between a UPF 30 and UPF 50+ shirt is usually small, but the protection gap compounds over a full season on the water.
Don't Forget: Fit and Coverage Matter Too
A high UPF rating only protects the skin the fabric actually covers. A hooded, long-sleeve shirt with a UPF 50 rating will protect your neck, ears, and forearms in a way a UPF 50 short-sleeve tee simply can't. If you're prone to sunburn on your neck or the backs of your hands, prioritize coverage first, then rating.
What to Look for on TideForge
Every shirt in our Men's UPF Sun Protection Fishing Shirts and Women's Fishing Shirts & Apparel collections is built for full-day wear on the water, not just a walk to the mailbox. A few good starting points depending on how you fish:
- Men's Marlin Groove L/S UV Fishing Shirt — long sleeves for maximum arm coverage on open water
- Men's Sail Fishing L/S UV Fishing Shirt — a solid everyday long-sleeve option
Fishing with kids? Sunburn risk is even more important to manage early — check out our Kids' Fishing Apparel collection for sized-down UPF gear built for the same conditions.
The Bottom Line
UPF 30 isn't a bad choice, but if you're spending real hours on the water, UPF 50+ is the safer default — the extra protection costs you almost nothing and covers you on the days you stay out longer than planned. Match the rating to how you actually fish, prioritize coverage on your most sun-exposed spots, and you'll spend a lot less time thinking about sunburn and a lot more time thinking about the next bite.
Fishing saltwater specifically? Sun isn't the only thing your gear has to survive out there — see our guide on what salt spray actually does to your gear for how to keep everything lasting past one season.
Not sure whether your trip counts as inshore or offshore? See our guide on Inshore vs Offshore Fishing for how gear priorities — including sun protection — shift between the two.
Outfitting the whole family? Our parent's guide to UPF gear for kids covers what to look for on the water, including what pediatric guidelines actually recommend.
Packing for a coastal trip? Our Coastal Fishing Trip Packing Checklist covers exactly what to bring, sun protection included.