Mine are a 10 to 10 1/2 which seem about right. I\'ve worm them once on kelp rocks etc, and to be honest they feel more like wellies than boots as your foot moves about inside them due to the thermal sock. They do grip quite well though, are easy to walk in and are warm...But having just checked them for faults I\'ve found that one of the eyelets is faulty and some of the material just above the rubber has come away from the stitching. Might just be a dodgy pair but they are going back! Hope the replacements are better.