Pisa Train Station - Luggage

There is luggage storage at Pisa Centrale, but check for hours of operation. I haven't used the deposito baggagli at Pisa Centrale but I have at many other Italian train stations and nothing has ever gone missing.

We were there two years ago and yes, there is luggage storage in a storeroom with an attendant. Station hours then were 0600-2200. I think there was a 3 euro charge for each bag. The luggage storeroom was at the far east end of the train station. When you come up from the train tunnel, which runs under the platforms, face the station with the tracks behind you. The storeroom is to your far right. If you are going to the leaning tower then you can catch a bus right out front of the station at the piazza. Remember to have your leaning tower tickets ahead of time.
Have a great trip!

yes, you MUST have advance tickets to go up the tower, and there is mandatory storage there for your purse or backpack. if you want to do the baptistery or cathedral......you can get a ticket in advance....but get to keep your purse

We routinely use these bag storage offices for packed clothes and souvenirs, without issue. I would plan to carry electronics or other valuables with you as much as possible (or leave them at home). In some stations (such as Roma Termini), staff have required me to have a lock on my bag (which I always do), so that they could not easily be accused of opening it.

Just to add a little further to Steven's comment.

The signs for the luggage will read “deposito bagagli"
When you get off the train, the deposito bagagli is to the right at the far end of Platform #1, close to the police office.