The entire area served by Prague Integrated Transport (PID) lines is divided into zones. The assignment of individual stops to particular zones determines the price of a journey between these stops. In Prague there are zones P, 0 and B. Outside Prague (in “Region”) are tariff zones numbered from 1 above.
If you only travel within Prague, than all zones can be considered equal and one can use tickets for Prague, regardless of the zone assignment.
The zone assignment of stops in Prague is important only when travelling between Prague and Region, ie. when using suburban lines 301 to 399 or train lines that go from/to Prague. On these lines, all stops in Prague belong into zones 0 and B, while on urban lines (metro, trams, urban buses 100-299, funicular, ferries) all stops are placed into double-zone P. This means that zone P overlaps with the zones 0 and B at those stops that are served by both urban and suburban lines. For instance – metro station Zličín belongs into zone P, while for suburban lines the same stop is in zone B. Train lines are the only lines that cross all zones from P in the center, through 0 and B to 1, 2, 3, …
When you buy a ticket for suburban travelling, the ticket has limit on time and on number of zones. These are the only limitations, otherwise the ticket is fully transferable. When you travel, all zones that you go through are calculated, even though the line does not stop in that zone. The zones are adjacent in this order: P, 0, B, 1, 2, 3, 4, 5, …, or …, 5, 4, 3, 2, 1, B, 0, P. For instance, if you go by a suburban line from zone 3 to zone B, where you change to an urban line and continue to the city, you always need to have a ticket for at least 7 zones (3, 2, 1, B, 0 and P, which is calculated as two individual zones).
The assignment of stops into individual zones can differ from line to line. It is determined by the timetable of the individual line.
The PID zones are illustrated on the following picture.