best way to get from Florence airport to Siena by public transport?

Ronny,

When you arrive at FLR, take a Cab to Firenze SMN rail station. They have a fixed rate (can't remember the exact amount but it may be about €20). There's also a Shuttle, but after a long flight I don't usually like to bother with that.

From Firenze SMN you can easily take a train to Siena or you can walk to the nearby Bus depot and travel by bus. Either train or bus is a bit more than an hour. The advantage of the Bus is that you'll be dropped in the main part of Siena, rather than the bottom of the hill where the rail station is located. If you travel by train, you'll need to take a Cab or Bus up to the town.

Thank you Ken!

Does anyone know the bus schedule link for times of buses. My husband and I will be traveling to pisa from sienna. We will be traveling on a Sunday and I've read the bus schedule is reduced on Sunday's. Any suggestions or advice for best travel in late September.