My toddler has sensitive skin and this cotton jersey tee hasn't irritated him once, even after a full day of running around. It's thin and breathable enough for hot afternoons but has held up through several washes already.
Bought this for our beach trip and it held up through sand, sunscreen, and two ice cream cones — still looks new after a wash. The fine jersey cotton is breathable enough that my daughter didn't overheat running around in the sun.