The reviews did not even remotely prepare me for how small these shoes would fit.  I am a 9.5-10 in women's shoes, and can wear a size 9 in sandals.  I assumed that a 9.5 would fit okay without socks in a water shoe, even though the reviews said they ran a bit small, since most of my sandals are size 9.  I got these 9.5 shoes out of the box and they immediately looked extremely tiny.  I forced my foot into it (it was not easy) and found that it fit more like an 8 or 8.5.  I have never seen a shoe this undersized before.  I don't even think a 10 would have fit...I probably would have to order a 10.5 or 11.  Since my vacation starts before an exchange could happen, I'll just use sandals I currently have for the water.  Oh well.  You'll have to order a minimum of a whole size up on this one, likely a size and a half.  I'm not sure what Vasque's reasoning was behind sizing shoes this small, even though they are meant to be barefoot water shoes.  It was my first experience with this brand, and I'm not impressed.  I'll stick with Keen and Merrell.