Until the 1970s, the port of Kythnos had no permanent inhabitants but, with the growth of tourism, it urbanized and, during summer, it's apparently quite lively. (Unfortunately, we haven't visited Kythnos yet...)
Merichas
Kythnos is served from Piraeus (Western Cyclades lines) and from Lavrio via Kea (Tzia).
CONTACT ADDRESS
No info available, sorry.
(You may find a contact on the website mentioned below.)