As these are very flexible the sizes are forgiving. They are meant to be worn comfortably skin tight, so if you are in between 2 sizes, order down a size. The idea is that by having them fit skin tight, they will keep the sand out of unwanted places! These are first quality, brand new shorts and will be a lifesaver for any surfers or body boarders out there. Stop the problem before it starts and wear a pair of these when participating in all water sports!