travelling to Rome, Italy

With only 7 days (how many nights?) you can only visit Rome and Venice. If you can, fly to Venice and fly back from Rome with an open jaw ticket. If you can’t change your flight, take the train from the Rome airport and go straight to Venice after landing in Rome (4.5 hour journey). Spend 3 nights in Venice. Then take the train back to Rome and spend the last 3 or 4 nights in Rome before returning back home. By going to Venice upon landing you save one hotel change.

We most likely will take train. Do we need to stay in Florence also .Or we can go from Venice to Florence or Milan.How much time do we need to see those cilties.
Thanks

Can you give us your actual arrival date in Rome and actual departure date home? Just checking that you really do have 7 sightseeing days. And what country are you flying from, and what month?

It may be a little tiring for the kids but how about taking the Freccia train from Rome to Venice? It's about a 4 hour ride but the train is very comfortable (maybe the kids could nap?). After a few days in Venice, then head to Rome for the balance of your vacation days. The kids might enjoy Rome more than Venice. I would think your return flight is in the morning from FCO. Maybe have your hotel make the arrangements for a car service (same price as taxi).
Honestly, I don't think you have enough time to do another city besides Venice and Rome. Count the number of days and nights that you are actually in Italy - not flying across the Atlantic in either direction.

Two days in Rome means three nights and does not include Vatican City which the kids wouldn’t enjoy. Last Jul I traveled with a seven-and five year old and the seven year old wanted to spend time at the beach but then again we were in GR.
Are you locked into flying in and out of Rome? If you can change it, it would be best to fly in and out of Venice and Rome. Most people prefer flying into Venice to avoid the hefty water taxi ride to the airport early morning. The other alternative is taking a direct bus from Piazzale Roma to Marco Polo airport but that works if flying out of Venice late morning.
Why Florence with kids? Florence is a museum city. Kids are not into 11th century fine arts and Michelangelo’s David, although they will stop and look; furthermore, you don’t have time. You need to return to IT to explore Tuscany without the kids.

You don't need to stay anywhere unless you and your kids are interested in staying there. You are on holiday.

What you should really do, in my opinion, is looking for the cities you have mentioned on a map of Italy that shows the high speed railway lines: https://images.app.goo.gl/s99wJenfEmK2hFkg6

Thanks every one .We are arriving on 6/21 at 7.30 am and leaving on 6/28th . From the same air port. FCO airport. I want to creat a smooth travel plan with kids without exhaustion.
AN

That is 7 NIGHTS which is 6.5 days. That half day hardly counts due to jet lag.

I’d stay in Rome for the whole time

Other option ( since you want Venice)
Is to head to Venice immediately upon arrival
Venice 3
Train back to Rome 4

Each location change with that plan will consume more than a half day -and traveling another 4 hours by train after an overnight flight MIGHT be a disaster with the kids

That is 7 nights on the ground.
I reiterate that if you want to include Venice in your trip it is best that you should go to Venice upon landing by train.

The journey from the Fiumicino Airport station to Venice Santa Lucia (right on the grand canal) is less than 5 hours and there are at least two trains every hour until past 6pm. With a 7:30am landing you can easily be in Venice by 2pm. Nearly all trains require you to change at Roma Termini or Roma Tiburtina, Rome’s main stations. There are a couple of trains that go from the Rome Airport to Venice without requiring a change, but the first one is in the early afternoon so you would need to wait too long at the airport since you land early. I know that you will be tired after a long flight, but once you take the Leonardo Express train from the airport to the main station, and you get on the high speed Frecciarossa train to Venice, you have 4 hours at your disposal between Rome and Venice where you can sleep on the train if you want. Trains are very comfortable, they aren’t like airplanes.

With only 7 nights I don’t think you have time for Florence.Florence also deserves 3 nights like Venice. Florence is exactly half way between Rome and Venice. The high speed train between Rome and Venice also stops in Florence and Bologna along the way.

You could do 2 nights in Florence, 2 in Venice, and 3 in Rome (in this order, or Venice first then the others), but you would shortchange all 3 cities, and with small kids all those hotel changes and packing and repacking each time would be very stressful and time consuming.

Unless you can change flight to open jaw, i.e. fly into Venice and out of Rome or vice versa, I would also recommend just staying all 7 nights in Rome. There are so many things you could do to fill in a week in Rome. You could take an easy day trip to Ostio Antica, which your kids may like. If you go to Venice for a stay and back, you will lose a whole day of your limited 6.5 days to just sitting on the train (8 hours round trip). Rome is pretty hot in June. Your kids, especially the 5 year old, may need to go back to the hotel to rest during the day, so your vacation days will probably be short. I doubt there will be very many 10 km walking 3 attraction days for you and the kids. You need to make the best of your time and energy and not waste them by packing, unpacking, checking in and out and sitting on a train, which is pretty boring.

Listen to Roberto. He has given you a good plan, not too rushed. Taking the train form Rome to Venice on arrival means anyone who needs a nap can take it on the train. There is food available on the train, too, or grab sandwiches before you board. Two cities in a week is plenty, especially with 3 kids.

Alternate recommendation is to enjoy Rome the whole time and not worry about what you missed. Embrace the chance to go to the zoo in a foreign country, ride bikes in the park, act like locals for a day doing things you might like to do at home. It's not all about art and ruins.

Thanks.
How soon we should buy city card or train card .Or we can purchase it at the train station. What are our options. Any site links will be appreciated. Similarly for the city attractions.
Thanks
AN

If you haven’t already I suggest you pick up RS Italy guide book
You can also get a Kindle version and begin researching right away

You need to settle your itinerary first then make your list of what YOU want to visit
Once you’ve done that we can give you specific advice on booking tickets and entries
You have plenty of time til a June trip

I think 7 days is too long for Rome, I'd add at least one of Florence or Venice. I spent 4 nights in Rome and by the 3rd night I was ready to go to a different place. I get restless easily, always wanting to explore new things.

Roberto did have a good plan. June is going to be hot, so be sure and book rooms with AC. I think the kids would enjoy Florence, probably more so than Venice. There is a lot to do in Florence. What are the ages of the other 2 children?

I'm doubtful about the value of a sightseeing card when you have three children, with one as young as five. How many covered attractions will you really get to? Won't the kids be more interested in active pursuits and gelato?

I agree with some of the other responses. Staying in Rome the entire time would probably be best. Depending on flight times, you're likely to have no more than 6 days on the ground. We have done day trips from Rome (Venice, Florence, Naples) in the past but our youngest child was 12. While in Rome you could take some shorter side trips to Ostia or Tivoli. Commit to returning one day and your itinerary building will get a lot easier. Good luck!

I want to create a smooth travel plan with kids without exhaustion.

To do that you need to limit yourself to no more than two locations, doing Rome at the end if you choose to go to the 2nd destination.