My usual size in Fly London or any other European-sized shoe is 38, as I'm a 7.5M in US size. This sandal runs too short for me, with my heel slightly overhanging the back edge. Not a good look, and not comfortable. Rather than run the risk of a larger size being to big, and not wanting the hassle of returning them to the seller in the UK, I kept them and sold them to someone with a slightly smaller foot.