Here some basics:
For Croatia, see: http://www.cronatur.com/
In Ohrid in MK t
There is a nude resort (only one in Montenegro) on an island of Ada Bojana on Albanian border, south of Ulcinj/Ulqin. They may take non-package holiday guests if not fully booked and you can also accommodate nearby and go to their beach if not want to live there. Contact them to know more. Here some local page about the place: http://www.ada-bojana.ulcinj365.com/
I know nude beach next to Sutomore but haven't been there for years (in
90's it was nice, but very few tourists back then) and recent Czech critics was
There also is near Herceg Novi this place http://www.full-monte.com/ but it is not at the seaside.
Jaz beach near Budva used to be OK but I heard it is not nude any more.
Njivice next to Herceg Novi has a hotel Riviera with its own beach, part
of which is nude beach. It is comfy and nice, also not far from Full
Monte campsite if you opt to stay there. Though hotel beach, it at least
used to be accessible to non-guests, too.
For Macedonia/Ohrid, traditionally nothing but some remote spots were OK for nude sunbathing. There some other developments, though: