These sandals were long enough for my almost-3 yr old boy who wears a size 8 in other shoes. But the were not wide enough. His feet are still a little bit chubby--like baby feet--and so I could barely get these sandals on him and then the immediately cut into the sides of his foot leaving a mark and looking very uncomfortable. I ordered up a size, and the 9 is working well for him.
It's possible that with an older child you could "break in" the 8 and it would have worked. I just can't really gauge my 2 yr old's level of comfort or discomfort well enough to try that. --so that is why I opted to just go up a size.
Other than the width issue, I love these sandals. Cute style, classic little boy, love that they can go in and out of water, and they seem comfy. My son asked to wear them today after wearing them for the first time all day yesterday. I bought a similar pair for my 4 yr old daughter as well.