My friends who have houses on Sifnos remind me that bars come and go with amazing rapidity; many don't last an entire season. I'm not listing phone numbers because phones simply are not answered. The main street of Apollonia vibrates to the sound of music from virtually wall-to-wall bars all summer. Of these, the Argo Bar has been around for years; it plays European and American pop music with some Greek tunes thrown in.
In Kamares, there's another longtime survivor: the picturesque Old Captain's Bar. For classical music, the Cultural Society of Sifnos sometimes schedules summer concerts in Artemonas.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.