Day trip from Rome to Florence

This is not worth it; the stations are crowded.

Why not just stay in Rome?
Even with your 6 pm departure it’s a risk I would not take, stuff happens.
You’ll hardly have more than a few hours in Florence-exactly what to you intend to see and do?

I wouldn't do this unless I was without kids and only had a carry on bag. Even then there would be very little of Florence that could be experienced in that one afternoon and evening. With a later afternoon flight, and needing to be at FCO 3 hours before the flight, you would have to be on the train from Florence at least 7 or 8 hours before your flight. Many sites are closed Mondays.

I should add: We will stay in Rome for 3 nights before the cruise, so I thought Florence would be worth a visit.

So you basically have just 2.5 days in Rome at start of trip?
That’s nowhere near enough time!
I’d see more of Rome on this final day
Assuming you will have visited Colosseum etc already
Maybe a ride out to Ostia Antica would be fun for kids? Visit Capuchin crypt? Take a food tour?

No, really not a great plan trying to see Florence. I would skip the Vatican during your pre-cruise days and see the Borghese Gallery instead (closed Mondays). It’s fabulous. Then you’ll disembark Sunday. By the time you get your bags, ground transportation, you’d be lucky to get to your hotel in Rome by noon. Have lunch, the day at leisure. Book a first entry tour of the Sistine Chapel the next morning. See the Sistine Chapel without the crowds (really quite different) the Vatican Museum, St. Peter’s. Back to your hotel, have lunch, get your bags and head for FCO. Taxi’s are cheap so use them.

Excellent idea Alan

And agree- Borghese is a must do
Spend some time in the park there afterwards

I'm going to buck the trend here and say going to Florence for a night is doable. If your ship docks early, you could train to Florence and arrive midday. Why not just take your luggage with you and save the time checking and retrieving it? I'm guessing a 6pm flight from FCO isn't international, so you may only need to be at the airport about 2 hours before departure. That means you could leave Florence around 1pm and still comfortably get to the airport. Is this an ideal plan?. No, but it is doable if you really want to see just the minimal highlights of Florence. Note that even if there's a rail strike, many high-speed trains between Florence and Rome will be running and the Leonardo Express always runs during strikes.

Another reason this is a bad idea is that Termini is the wrong direction from Civitavecchia. That train takes about an hour, depending on the local stops. And they might not be the first group off the ship. And they might have to wait to fit on the bus to the train station in Civi.

The penalty for missing the plane on Monday is pretty severe. Do you feel lucky about the 3PM check-in? What month of the year will this be? I would not spend my departure night that far from the airport, even in a country with a less ... er ... Latin reputation for promptness. (In fairness, my Frecciarossa trips have been impressively professional. But I've had delays and failed air conditioning on trains between Venice and Florence.)

The only plus is that the Florence train station is well-situated for some attractions, and has decent hotels nearby.

I realize that I have more disposable income than many other people, but is this your only chance to set foot in Florence in your entire lifetime? There is more than one day to see in Florence, and some of the attractions, like David and the Uffizi can have miserable crowds. Is there lead time to buy discount Frecciarossa tickets, or enough time to get timed Uffizi tickets or (for that matter) Borghese tickets?

with kids in tow?

how many and ages ????

Does the 6PM flight go to another Schengen country? If so, 2 hours before flight generally would be OK. Anywhere else, less than 3 hrs ahead is taking a risk most here would choose to avoid.

If you want to spend the night somewhere not in Rome, perhaps Orvieto? Or stay in Fiumicino or Ostia and have a 'beach' day.

If the kids are less than teens, I think you are setting yourself up for an experience that is more exhausting than enjoyable.

On the positive side, everyone should be so worn out, all will be asleep before the plane reaches cruise altitude.

To answer your question "Too ambitious? ", I would say 'yes' Looks like a lot of work to have dinner and breakfast in Florence

My $0.02

The flight is back to the US, and the kids are not teens yet. So I guess it's too ambitious a journey.

They read stories about renaissance and are fascinated by the idea of Florence. We'll try to make it in a future trip then.

Thanks everyone! Alan: your plan sounds perfect!

If you have time during your pre-cruise days: https://www.palazzovalentini.it/domus-romane/index-en.html. This is a short walk from the Colosseum right near Trajans Column (there is a connection, but I won’t spoil it). It’s a multimedia presentation of an archeological find. For much if it you are walking on an acrylic floor looking down. You need to book in advance, be sure it’s the English tour. We’ve seen all of Rome, several visits. This was a highlight of our last trip and we wished our kids were with us to see it.

Thank you, Alan!

Alan's comment triggered another idea. You could take a day trip to Florence during one of your pre-cruise days in Rome and then spend the day after the cruise seeing your remaining sights of interest in Rome. There are multiple high-speed trains per hour between Florence and Rome, so you could return whenever the children start to get tired. A day trip also solves the luggage storage issue.

NO, Florence takes days to see well. Also, lodging in Florence is relatively inexpensive compared to Rome. Stay at least one night.

We liked the Hotel Balesteri, it is on the Arno at a central location.

I'm not sure about the train from Civi to Termini, but the family and I did a day trip to Florence from Rome and had a wonderful time. My kids were 9 and 12. We took a 7:30am train to Florence and returned on the 8:00pm. We could have taken a later train but I had prebooked the tix. We had more than enough time to see what we had planned to see. Sure there was more but there always is. You just have to pick what's important to you.
We never stored anything at Termini, but we did store bags at the Naples train station and that turned out fine.
Not sure when you are going. We went in May and it was busy but manageable.

We are going in mid-June. Another option is to have half of the family staying in Rome while the other half heading for Florence, luggage free, and coming back to Rome in the evening.