There is a very good train service between Rome and Rome's Cruise Port, Civitavecchia. The core service is broadly a twice hourly service on commuter style trains taking around 70 to 80 minutes to travel the full route.
By train - travel time approximately 2 hours. Take the FR1 suburban train (not the Leonardo Express) from FCO towards Rome and get off at the Trastevere station, where you can change to a local train to Civitavecchia. Reverse if going in the opposite direction.
You can though use the two stations visited by the Civitavecchia Express as a jumping point into the rest of Rome, civitavecchia train through walking, taxi, bus or metro.
Important: If you're going out https://letsgoincruises.com/adventure/dream-adventure-trips.php your own be sure to allow plenty of time to get back to the civitavecchia train These numbers are active every day civitavecchia train 6.
The few taxis present in civitavecchia train do not transfer to the train station in Civitavecchia.
How to get Civitavecchia Port from Rome and from Airport. letsgoincruises.com
From here you can civitavecchia train train link of the free civitavecchia train that run regularly and that will take you to your terminal or departure quay.
With the station building behind you, turn left at the back of the square down the Via Innocenzo, a one-way street with here traffic including the buses coming towards you. Departs from Airport civitavecchia train 11:30 am arrives at port by 12:30 pm.