I love these undies for my potty training toddler. They are thick enough that if she just leaks a little, like when she doesn't quite make it to the potty in time, it doesn't leak through to her pants. However, she still feels wet and knows she's had an accident-unlike a pull-up. They are super soft and she loves the cute designs. They fit perfectly and she wears a size 5 diaper for reference.