The network is divided into three concentric zones; all Zagreb's tram routes operate entirely within the central zone, so you'll only enter the outer two zones if making an out-of-town excursion by suburban bus.
Regular bus and tram services run from about 4.30am to 11.20pm, after which night trams come into operation. Night services operate different routes from their daytime counterparts (although they use the same stops), and run at irregular intervals (usually every 40-50min), so knowing when and Tickets are brought from ZET kiosks at major tram stops and terminuses, tobacco (duhan) kiosks, some newspaper kiosks or by cell phone. There's a flat fare per journey: single-zone tickets are 8 kn from kiosks, 10 Kn from cell phone. All kiosks
62 also sell day tickets (dnevne karte), which can be used for unlimited travel within a single zone and are valid until 4am the following morning. All tickets are validated by punching them in the machines once on board.