I've owned Reef sandals for the past few years - probably 8-10 pair or so.  I love these sandals, however, the inconsistent sizing between styles can be frustrating when buying these online.  I wear a 13 in some styles, a 12 in some styles, and even as small as an 11 in other styles.  If you've never purchased this particular style before, I would recommend buying them in a retail store so you can try them on first.