This is a great question. Our first explanation would be based on length, and whether you would like a liner. We have 4 lengths of shorts, and lined/unlined:
Sextant Trunk: 6” inseam (our shortest)
Bayberry Trunk: 7” inseam (lined)
Anchor Trunk: 8” inseam (lined)
One Short: 8” inseam (lined AND unlined option)
Nautilus Boardshort: 8” inseam (unlined)
Rockaway Boardshort: 9”inseam (unlined)
Once you have an idea for length and liner - we suggest going to the product pages where you can find a description of the shorts, their suggested uses, and their fits. Of course, if you have any questions whatsoever, we are more than happy to assist you with fit/sizing/description questions at info@fairharborclothing.com