florence to pisa with eurail global pass

For all of Italy:

If your train is a Regionale or Regionale Veloce, you do not need a reservation. You can just hop on with your pass.

If your train is an Intercity or a Freccia (FrecciaRossa, FrecciaArgento, etc), you need to buy a a reservation before getting on the train.

Looking at the schedule, it seems the trains between Florence SMN and Pisa Centrale stations are Regionale, but it never hurts to check the specific train you are taking, so you don't get a fine.

In addition to the comprehensive primer given by Harold above, if your train is an Italo Treno (nationwide super fast train) or a Circumvesuviana (slow commuter train to Pompeii), anything operated by TreNord (commuter trains around Lake Como and Milan) or Leonardo Express (train between Rome's main airport FCO and Roma Termini station) you will need to buy a ticket. None of those private or local train companies will accept your Eurailpass, Global or any other kind. Same is true with a number of private rail companies in the southeast of Italy.

barry,

As the others have mentioned, the answer will depend on what type of train you're riding on. The majority of trains on that route are Regionale so you can just use your Railpass. However, if you were riding on a Freccia or InterCity train which requires compulsory seat reservations, you MUST have a reservation in addition to your pass, or you'll risk hefty fines which will be collected on the spot!

Using a Railpass for that route will probably not be cost effective, as the daily cost of the pass will exceed that of the cheap tickets.

Just buy your tickets for the regional train at the Florence train station to Pisa , about a 45 minute ride into the center of town , then it's about a 20 minute walk through the town to the leaning tower, stop at one of the many cafes for a gelato or drink along the way or they probably have some type of shuttle if you needed