What type of fabric to use when making boardshorts?

Does anyone know what type of fabric and where to buy in order to make boardshorts/swim trunks for boys/men?  I would like to make my husband and son bathing suits for this summer like the ones you see in the stores, but where on earth do you buy the fabric from?  I've searched the web and finding nothing really.  I found one fabric only from the fabric fairy for boardshorts, but it is just a beach scene.  I'd like to find some solids.  Thanks for any suggestions.

There are nylons [mostly] and poly's.  RCT Fabrics [www.fabricline.com] is an excellent resource, and if you call there, you can talk to Annette, who manages the store and is very helpful and knowledgeable for all activewear fabric [and sewing].

I recently made beach shorts from a stretch nylon that I bought there -- I made pairs for the whole family, actually [capri's for me, shorts for the kids and my husband].  I haven't posted them all yet, but I did post this one, so you get a feel for the type of fabric:  https://twitter.com/johnnymangoseed/status/222851030331834373/photo/1

It is one of the great liberations of sewing, for me, because I haven't seen long board shorts [let alone with stretch and an adjustable waistband!] for sale for girls, and these are great for the beach and the lawn.  I am so grateful for sewing!

Good luck, and enjoy!
Pamela