If you want to travel the 203 miles (327 km) from Venice to Pisa, your best option will be to take a high-speed train to Florence and then transfer to another train to Pisa. You could also drive, or hire a private driver. Driving will give you the option to explore a few regions of Italy along the way.
With a few more days, you could even consider this 6-day itinerary to see Venice and Florence before visiting Pisa.
Duration: 3.5 hours
From Venezia Santa Lucia station you can catch the Italian National Railway system, Trenitalia, or its competitor, Italo, for the 2.5-hour ride to Firenze Santa Maria Novella Station and then transfer to a regional train for the 1-hour ride to Pisa. You can show the conductor your ticket on your smartphone, for convenience.
Trains run about every 30 minutes to one hour depending on the time of day and year and will leave from Venice until around 7 pm during peak seasons. Because you are transferring in Florence, you could always spend a day exploring the Renaissance city before making your way to Pisa.
By Rental Car or Private Transfer
Duration: 3.5 hours, more with stops
If you start your road trip from Venezia Santa Lucia train station or Marco Polo airport, you'll have several rental car companies to choose from. It is possible to rent an automatic transmission car in Italy, however, manuals are more prevalent, and will be less expensive to hire. You’ll also want to factor in the cost of gas (prices are by liters, not gallons) for your road trip.
Being in a car will give you a chance to stop as many times as you want as you make your way to Pisa, as you pass through the regions of Veneto, Emilia-Romagna, and Tuscany. Traveling on the A13 autostrada, you could make detours to some of Italy's best-loved cities, for a few hours, or a few days. You might stop in Bologna, which is full of culinary delights. In Lucca, you can explore a quaint Tuscan town where you can walk along its medieval fortification walls.
Hiring a private driver is another option, making it easier for you to enjoy your time without having to navigate.