Rome

You'll get very good and accurate information from informed cruisers if you ask your question at Cruise Critic .com.

But it certainly won't take 3 hours to get into Rome. Maybe half that.

Your best bet might be to rent a car and driver who will pick you up at the ship and take you to Rome and drive you to various sites. Check out romecabs.com. it won’t be cheap but you will see something of Rome in relative comfort. Do you know what you want to see? In the short time available you won’t have time for museums, the colosseum might be a drive-by, but at least you will get a taste of the city.

The trains take between 50 mins - 1.5 hours but of course you need to allow time to get from the ship to the station, and that depends on where you are moored - if you are at the far end of the wharf you will have a long treck.

Also might be worth doing a ship’s excursion.....

I haven't been on a cruise to Italy but I've been on cruise ships. How long it takes to get off the ship depends partly on how many passengers are on the ship. If it's several thousands, it can take up to an hour. Priority goes to priority passengers (those in the best cabins and those who are frequent cruisers) and often to those on the ship's tours. After that, it's everyone else who has lined up. If you are among the first in line, you'll have a long wait, but still be off the boat before a lot of other passgeners.

This is precisely why we are doing our ship’s port excursion for Rome. If you look at the excursion descriptions, it should tell you how long it takes. For example, mine cites a 90-min bus ride each way to/from Civitivecchia. We leave at 7:15 and get back at 6:15. So that will be 8 hours of touring, 3 hours of bus riding. As a PP said the cruise line will give priority to those with a cruise line tour and let them off the ship first. Most importantly to me, they will hold the ship for us if we are late. I’ve heard horror stories about the Rome to port traffic and even Rick in his Med cruises book says ship excursions to Rome are a decent strategy.

On our first cruise to Europe 20 years ago, we cruised on a mid size Century ship and here's what we learned:

1. Ship excursions were first off - so you definitely had more time in Rome if you took their tours.
2. We opted for a "travel only" tour - see if this is still an option. The bus took us in to Rome and picked us back up at a certain time.
3. We were on our own which was awesome, but we didn't have to worry about traffic making us miss the ship.
4. We did hit traffic in to Rome, so our total drive time was 2 hours.
5. It did not take us an hour to disembark ! But we didn't have 4000 passengers either.

Marie, We've actually cruised in and out of "Rome".

Rome is actually some distance from the port. So far as excursions, you can do it cheaper on your own and many have done so and will advise you to do the same. If you take an excursion offered by the cruise line you will pay more. But they will wait for you if the excursion is late returning. That is not the case if you are just off on your own. Several times our ship excursions in various locations were late getting back but the ship waited. On several occasions on different cruises we have seen people left who were literally running down the pier after the ship was moving away. I guess a good rule of thumb is that if you are going to be staying close to the port and can hoof it back if you have to, then doing it yourself is ok, but if you plan to go far afield (to Rome itself) that's a different deal altogether. Going to Rome from the port will only afford you a once over lightly experience. I don't mean to put a damper on your plans, just want to give you the benefit of our experiences.