I wear woman's 8.5 and the 39 fit well, but with no room to spare. I adore these sandals, especially with the removable strap, but sadly need to return them, as another reviewer stated, the pretty flowers on the footbed irritate my feet after. I have the lower version of this shoe, but wear them with socks instead of sneakers in warmer months. The shoe is great in all ways, cushion, width, adjustable straps, with exception of footbed irritation (but my feet are super sensitive, so I doubt this would bother others). And they are waterproof!