I ordered a 9 1/2 M.  The top part of my foot would not fit under the straps.  My foot fit perfectly left to right so I don't think a Wide would have helped. I do have a lot of trouble finding shoes that fit me correctly and this one is a shame because it really looked like I would be able to wear them to and from work (subways and buses) instead of my clunky sneakers. Material-wise they reminded me of Crocs.  I would like to try the wide to see if that helps, or maybe even a size 10 but I can't keep shipping back and forth paying the shipping costs so I'll try to find in the store.