Background: I studied abroad in Siena 11 years ago and am attempting to give my sister advice who will be visiting in July. I had advised her to take the bus from Florence to Siena and back (staying two nights) and when I was there you could not purchase tickets online. I see now you may be able to for Tiemme (not sure it would work for the Sena buses - if those still run, too). In my memory you would just go to the tabacchi beforehand and buy a generic bus ticket that you would validate on either bus company (I think it was TraIn and Sita when I was there) when you got on board, but perhaps my memory is wrong. Is she ok to wait until she arrives in Firenze for the ticket to Siena (and then in Siena buy the one back to Florence) or will they potentially sell out ahead of time now that they are sold in advance? Also, does she have to buy for a specific time or is my memory actually right that it's a general bus ticket that can be used any time once validated? Grazie mille!