The size 6.5 put my toe right against the front of the shoe, so I ordered a 7. The 7 doesn't allow much additional room at the toe, and is way way looser around the rest of my foot and ankle area - so loose I wouldn't be able to keep it on in the water. Overall seems like a great shoe, but I will have to go with the one that's slightly too small so it stays on my foot. Kind of weird that the shoe is looser around the ankle as it sizes up, but not much longer. I don't like that at all.