We purchased these when my son was 15 months old and was measured a 6, I thought since these should last until he measures a 7 they would be great with the insert for a while and then a while longer without. I purchased the same size fo Pediped sandles in the same purchase, and they were too big for my son for a month, so either the sandles ran really big or these ran really small. Both were part of the Flex line... Not for us, he couldn't wear them with the insert at all they just run too small for that. They are a great quality shoe and I would purchase again, but just know that they run small. I'm giving 4 stars because of the quality of the shoe!