We are off to Kos too in mid september staying in Kos Old Town, we found this page on the web about nudist beaches in Kos.
http://www.capnbarefoot.info/dodecanese:kos
Hi guys. We've not been to the beach before but it has good write ups for nudists, and that's Tigaki. We're out there 11/21st September. Can't wait!! xx