I purchased two of these sun hats for my daughters, ages 3 and 5, and they're absolutely perfect. I purchased both in the size XL (my girls are above average size, so a L might work for another 3-5 year old). The adjustable drawstring makes these hats fit both my girls, with room to grow and without slipping off their heads, so I don't need to worry about their hats coming off when they're actively playing outside. The cherry on top is how adorable they are.
Packaging is environmentally friendly, included a sweet note from the seller, and shipping was incredibly fast. Overall, this has been the best purchase of my summer :)