By train: There seem to be two viable train connections taking 2:30 to Volterra. They require a change in Cecina. See trenitalia.com/cms/v/index.j...
By car: Take the highway A12-E80 south direction Rome until Cecina and then exit to Volterra. 166 km, about 2 hours to drive.
By bus: There probably are busses, but as La Spezia is in a different region from Volterra (Ligura - Toscana) it is hard to figure out which busses to take. That might be easier once you are in Spezia.
Hope this answers your question.
Be the first to rate this answer!