fast train from Rome to Venice

Purchasing on the day of travel, you'll pay the full "Flexi" fare on italotreno.it and the full "Base" fare on trenitalia.com

Both Flexi and Base are displayed in advance together with the discounted fares. You can't pay more, but if your plans are set you can pay a lot less.

Do I go on line to Italotreno.it or Trenitalia?

Your choice. Which company has the cheapest tickets? And a departure hour that best suits your needs? As you can see the time of travel is almost the same, but Trenitalia has more runs per day. Italo is often cheaper.

does this mean the extra persons in our group?

Sorry, I don't understand what you mean. eXtra seems just one of the 4 fares listed under that column. Click the small, grey " i " next to each fare name to read the T&C.

I see that Trenitalia is now charging you E2 to choose a specific seat!
You have to have a reserved seat on the high speed trains, but now it looks as if you'll just be given any old random reserved seat if you don't pay the E2.

It looks like Italo has a better price for that day at E29.90.

Remember with buying the advance cheaper tickets, you are locked into that specific train and time.

as if you'll just be given any old random reserved seat if you don't pay the E2.

I am not sure to understand what an "old random reserved" seat is, but you won't. You'll be given 2 (or more) available seats in the same car. As close as possible, to make conductors' job easier.
For the same reason, Before Covid, they tried to fill all the seats in each car. Today I don't know.

Thanks everyone for the fast and helpful reply's. I can do this! It seem the .italo witl be the way to go being 29.90 euro for May10th.

I already purchased Trenitalia tickets for May 29. I opted to pay for a refundable ticket so I can change it for another available train if necessary. We prefer to pick our seats too so it helps to do it in advance. I have done the Rome to Venice train and it was fine but there are other options to consider. In the past, not sure about in today's climate, we have hired a private taxi to take to FCO where we flew easyJet to VCE. If you're only taking a day trip I would encourage this as you are able to get to Venice earlier and without delay. Back in 2018 our train from Rome was stopped on the tracks in Tuscany for over an hour each way. I have found that easyJet flights are typically on time and not crowded very early in the morning. My daughter and I took an easyJet from Paris to Milan back in 2019 and our morning flight had about 20 people on board. Overall I prefer trains for domestic travel in Italy but there are circumstances where a plane can work better for the schedule. Good luck with whatever you decide.

Just to mention, the easyJet website states this when searching flights from FCO> VCE:
"Sorry, we don't fly directly from Rome Fiumicino to Venice Marco Polo"

https://www.easyjet.com/en/routemap

Maybe they did some years back but apparently not anymore.
Nope, train is the way to go, IMHO; no need to deal with the airports.
Jo, I'm guessing you aren't trying to do a trip from Rome and back the same day?

I agree the train will be best in our case. I've been to Italy many times, this is going to be a slow pace trip, just spending time with a dear friend. The easier the better for her physical condition. Flying into Naples and taking the direct bus to Sorrento for 6 nights, then bus to Rome for another 6 nights. We're flying out of Venice because the ticket was the best price at the time So the fast train to Venice, having 3 nts, the last being near the airport for a morning shuttle to airport. Thanks for the advice, its not too early to buy the train ticket....just making sure nothing changes.

If you will have a smart phone with you, download the appropriate app (Italo or Trenitalia), makes life easier, even to purchase tickets for other journeys, manage your tickets, etc.

Paul, the app sounds helpful, I better get with it, I'm more of a hard copy gal... Thanks for all the advice everyone. My friend is counting on me.

Kathy- thanks for the clarification on easyJet. ITA Airlines is currently operating that route and it continues to be an option for certain itineraries.
Thanks again!

We purchased our tickets in advance for our April travels. I signed up for the newsletter with Italo and keep getting discounts our tickets were 40% off so I highly recommend that we paid the extra $ to buy our seats as well. Since we got such a good discount it was worth it for me.