Light-weight cottons or linens. Long-sleeved shirts and long pants because of the skeeters. High-topped sneakers or waterproof light-weight hiking boots, with socks. Cotton cap of some kind, preferably with a netting to cover your face and neck from ...yeah...the skeeters and spider webs.
I actually went to Costa Rica 2 year ago and here s what I brought:some t-shirts, but mostly beatersbermuda shorts,hiking boots, sneakers, flip flopssocks!underwear (i had some that were spandex like- very helpful because they dry fast!)a light pair of pants for nighttimelots and lots of bug spray!!hope this helps!
The native women wear a kind of thong and a bone in their nose. I d go with that.