What size is recommended for a men's size 9 1/2?
CRAIG K If you are looking for a full foot fin (like a slipper) that does not require wet suit boots, then typically a size 9-11 fin would work. However, just as with women's clothes, and some men's, different manfacturers same sizes vary a little so you might find it is too loose in which case you can wear a thin air of socks or try the next size smaller fin. If you are looking for open heel fins to wear with wet suit boots, a 9 1/2 men's would be about the beginning of a large. If it is for a woman, I would go with a medium open heel fin.
SHELLEY G I think that would be a large.