I bought 3 pairs of this shoe, one for me I wear a women's size 9.5/euro 40.5 1 for my teenage daughter a women's size 9/39.5 and one for my 10yr old kids size 5. I ordered a men's 7.5 7.0 and 4.0 which on the shoe says it's a 40, 39 and 35 so a half size smaller than expected a full size for the mans 4 because a 35 is a womens 4, so order atleast a half size up. The material is a bit scratchy barefoot so need to wear a sock which you then loose a bit of the sheer effect of the shoe.