UPF sun shirts versus cotton
The Stitched Sailor crew · 2026-08-11 · 5 min read
This comes up on nearly every crew order, usually as which one is better. Neither is. They solve different problems, and most boats end up with both, because the shirt you want at eleven in the morning offshore is not the shirt you want at the dock bar afterwards.
Cotton is the comfortable one, and it takes a screen print with a depth performance fabric cannot match. A heavyweight combed cotton tee feels like something rather than nothing, softens with washing, and looks right off the boat. What it will not do is dry. Once cotton is wet, from spray or sweat or a swim, it stays wet, holds heat and gets heavy.
A UPF 50+ sun shirt is a tool. Long sleeves, a knit that moves air, moisture wicking, and a rating that means the fabric stops about 98% of the UV that would otherwise reach the skin under it. It does not wash off at noon the way sunscreen does and does not need reapplying with greasy hands. On a long day in open water that is not a comfort preference, it is the difference between finishing the day well and finishing it burnt.
They are decorated differently, and this matters more than most mates expect. Cotton is screen printed, so the ink sits on the surface, which is where that slight raised feel comes from. Performance knits are sublimated, so the artwork is dyed into the fibre. On a sun shirt that is the correct choice: a screen print on a technical knit traps heat where the ink sits and will eventually crack at the shoulder where a pack or a harness rubs. Sublimated artwork cannot crack or peel, because nothing is sitting on top to come away.
The practical answer for most crews is sun shirts for whoever is outside all day and cotton tees for everybody, because the tee is what gets worn afterwards and what gets reordered. Both carry the same approved drawing, so a set built across the two still matches.
If you want the close-cut version for boards or under a vest, the rash guard is the same UPF fabric in a slimmer cut. It runs small on purpose, so take the next size up.