Review on Finis Reusable Swim Diaper For Babies And Toddlers by Patricia Wilson

Based on a lot of reviews stating these ran small I went up a size and bought 4t for my 31lb almost 3 year old who is in between size 5 and 6 diapers. He is quite tall for his age. They are actually a bit big on him and 3t probably would have fit perfect but these should continue to fit throughout the winter if we still need to use them. So I would say if your child is in size 5 diapers as around 30lb the 3t size would fit just fine.