There is no simple bus connection between Pisa and Siena.
Map
Where can you go by bus from Pisa?
Tap a place on the map or in the list: you can see straight away where the bus takes you and how many departures there are per day.
Source: Regione Toscana, public transport timetables (CC BY). Timetables collected for 10/11 (weekday), 07/11 (Saturday) and 08/11 (Sunday). Check the day before on at-bus.it: school buses and summer timetables change.
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