Transportation from Civitavecchia to Cinque Terre (Riomaggiore)

You can book the train from Civitivecchia to La Spezia in advance on the Trenitalia website...same with your return from La Spezia to Rome. The train to & from Riomaggiore and La Spezia is a local train...just buy your ticket at the station.

1. You can take the train from Civit... to Riomaggiore -- about 4 hours, one change in La Spezia. Lots of options. See trenitalia.com. There is a train station in Civit. Actually two - one at the port.I would buy the ticket that day since you do not know exactly when you will get off the ship or to the station. The ship will get you to the port entrance and a bus will take you to the train station. The station will be a zoo especially if more than one ship in port but hard to avoid. It is about a mile walk to the port station. Taxis will not take you since they want the bigger fare of going to Rome or elsewhere. However, you might try for a taxi to the other train station. We have only taken the train from the port back to Rome. The other Civit train station would be far less crowded.

2. I would give serious consideration to returning home from Milan. Save time and money. You are closer to Milan than Rome when in Riomaggiore. Either way you will need to spend the night before in either Milan or Rome prior to departure. From Riomaggiore you would need to return to Rome via La Spezia and then take the Leonard Express train to the airport. You might want to look on a map to see where everything is and to organize your thinking.

3. If returning to Rome you could save money by purchase a discount ticket to Rome today. That locks you into a fixed schedule since the discount tickets cannot be changed or refunded. But since your are in Riomaggiore on your own, you have control of your time. For that run the Super economy ticket is about 20E compared to the Base fare of about 55 E. Considerable savings but no flexibility. Use it or lose it.

Use the website Rome to Rio to explore different routes and the website Man In seat 61 to get in depth explanation of trains etc.

I have walked between the port and the Civitavecchia rail station, but you don't want to do that without a single, easily rolling bag. It's over half a mile. The cruise may offer a $$ transfer to the train station, and there may be a shuttle bus from the cruise terminal (?), as well as the regular city bus, which is, naturally, very crowded. I think it's worth a taxi, but you have to decide. Most people on this newsboard can do two weeks with a roll-aboard suitcase.

As it happened, our small ship did not use a "cruise terminal", so we had to take a pier-to-port-transit-circle bus run by the port, to the edge of the port. We could not walk (not permitted) to the port transit circle.

Almost certainly, you will have to train to Rome Termini station, to get the special airport train, a bit of backtracking. That's just how it is.

Do some study at this website:
https://italiatren.com/en

You're likely to have to change at La Spezia for a very local train to Riomaggiore. It looks like 3 hours. Since you're not sure what time you'll get to the station, you don't really want a ticket for a specific train. Or you could pick the fastest routing after 9:30AM (?), and be pretty sure of making it.

https://www.ricksteves.com/travel-tips/transportation/trains

Directions from the port to the train station.

https://civitavecchia.portmobility.it/en/civitavecchia-train-station

I'll just echo Frank about spending the night before your flight to the U.S. nearer the airport, either Rome (Fiumicino) or Milan (Malpensa), depending on which one you choose. Both are some distance outside of the cities. You don't want to be in the Cinque Terre; it's too far away. Should there be some sort of strike or other transport snag, you'll want to be where multiple types of transport are available.

No, there are no ferries from Civitavecchia to the CT.
I'll also encourage you to travel as lightly as possible. The CT is not a fun place to have to manage large/heavy luggage. Where are you staying in Riomaggiore? When is this trip?

We will be disembarking on September 17 and returning to the US on September 21.We have reservations at the Best Western at the airport in Rome for the night of the 20th. This is where we are staying in Cinque Terre
Address
Salita Castello, 194, Riomaggiore, Liguria 19017, Italy
Hopefully we will be able to walk from the train station!

Good to hear that you already booked near the airport for pre-flight nite! :O)

About your accommodation in Riomaggiore, does this look like the place? If so, these reviews are old BUT the location and descriptions of what it took to get there won't have changed.

https://www.tripadvisor.com/LocationPhotoDirectLink-g187821-d1557420-i132500674-La_Scogliera-Riomaggiore_Cinque_Terre_Italian_Riviera_Liguria.html

https://www.tripadvisor.com/LocationPhotoDirectLink-g187821-d1557420-i39591845-La_Scogliera-Riomaggiore_Cinque_Terre_Italian_Riviera_Liguria.html

Is the name of the accommodation La Scogliera, and do you have website link?

This is the place we are staying:

Double Room "Dora" Amazing Sea View

It's an airbnb.
Hopefully, we can easily get there from the train.

Thanks for all the great info!