Before outdoor physical activities, children should drink water freely, and definitely shouldn't go outside already thirsty.
Clothing should be lightweight and cover as much of their skin as possible.
All exposed skin should be covered with a safe sunscreen of at least 30 SPF that protects against UVA and UVB rays (be sure to avoid harmful sunscreens and don't forget to reapply!).
Eyes should be covered with a pair of sunglasses that provide 100 percent UV protection.