The Vatican and Colosseum in 2 days.

Yes! Absolutely. You should buy tickets in advance to avoid a VERY long ticket line. You do that here:

http://www.coopculture.it/en/the-colosseum.cfm

General-admission tickets (€14,00 for adults) do not have reserved time slots so you can just skip the ticket line (but not the security check queue) whenever you can get there. I'd say anywhere between 1.5 -2 hours should be enough.

Ordinarily I might recommend doing the Vatican Museums during their seasonal late openings on Friday nights but not on arrival day when you're apt to be wiped out early. You need to be rested and wide awake for that one! The Colosseum - because it's outside - is a better choice in your situation.

The Vatican is crowded all the time aside from low season, it seems. If you really want to see at least the Sistine without a mob, book the early-entry tour with Walks of Italy or The Roman Guy: two resources that pop up frequently on the forum.

https://theromanguy.com/tours/Rome/Sistine-Chapel-Vatican-Tour

https://www.walksofitaly.com/vatican-tours/pristine-sistine-chapel-tour

Yes they're expensive but posters speak very highly of them. Both ALSO include St Peter's Basilica so a good way to kill two birds.

Otherwise, unless you're REALLY into art/antiquities I'd book one of the tours offered by the Vatican. They're fine, and will steer you to the highlights of the vast, 4-mile collection:

http://www.museivaticani.va/content/museivaticani/en/visita-i-musei/scegli-la-visita/visitatori-singoli.html

They offer a 3-hour combo tour of the museums and the basilica as well. In all cases, tours with any company which end up in St Peter's allow you to wander the basilica at your leisure when your tour is over.

I'm not sure how you could spend more than a couple hours tops at the Colosseum, it was fantastic but that was more than enough time for us! Went in the early evening on a Wednesday and it was nearly empty! Loved it!

Vatican you could spend days in but depends on what you like, for sure reserve tickets. Lines are crazy, you can skip them!

Pantheon was very cool, but only spent 30 minutes or so there.

We were at the Colosseum last year on Oct. 16 and the lines were very long. It was crowded inside so buy whatever access or tour that will make it an easier time for you.

Kirsten,

I'm not sure you'll be able to do a site such as the Colosseum on the day of arrival. I'm making the assumption that you're coming in on an international long-haul flight arriving FCO at 0900 (if I'm wrong, please forgive me). Even with perfect timing and carry-on luggage, I would be surprised if you can get to Termini by 1030-1100. Then there's the trip to the hotel (30 minute walk or 15 minute taxi ride after standing in the taxi queue for 15-30 minutes) and such. If you're traveling from north America, by the time you get to the hotel and drop of the luggage, your body clock will tell you it's 6:00am the day after you departed and that you've been up all night. The Colosseum is a pretty strenuous tour with lots of standing in queue (even with a reserved entrance time) and walking/stairs.

My suggestion would be to drop the bags off and then hit the major outdoor sights in the centro storico. You're hotel is within easy walking distance of the Pantheon, Trivi Fountain, Spanish Steps, Piazza del Popolo/Borghese Gardens, Piazza Navona and Campo de' Fiori. Hitting those sites should be a good jetlag mitigation strategy and a tune-up for the remainder of your Rome sightseeing. BTW - I would hit Campo de' Fiori first so you can catch the market before it wraps up for the day...

Even if you hit the major piazze during the day, hit them again in the evening - their personalities totally change. Also, you must go back to Piazza San Pietro in the late evening - it's absolutely stunning without the croweds!

The Colosseum has an elevator but that's the only thing that would make your visit less strenuous.

Thing is, if they don't do it on arrival day, it doesn't sound like they can do it at all? Friday (arrival day) and Sat. may be the only 2 days (actually 1.5 days) they have, and I wouldn't personally do the Vatican and the Colosseum on the same day unless there was no other option.

Maybe it's me but I don't recall the Colosseum being strenuous at all. We did it at the end a sightseeing day that included walking from Prati, the Capitoline Museums, Forum and Palatine. Sure, we were good and ready for a beer and a sit-down when all was said and done but managed the Colosseum just fine.

If you are pressed for time, and many may have another opinion...go to see the Colosseum but do not enter....I visited it in late Sept. early Oct. 2016 and honestly, without taking the under ground tour which seems to thrill people, you could get bored in about 10 minutes.

..the line was about 1 hour long..that time of year...due to everyone having to throw out their WATER and bags must be screened even if you prepurchased tickets..
I recommend going up to the neighborhood above the train station, just take escalator or elevator I think to highest part of metro station ( ask anyone when you are there) and sit in a cafe and enjoy the view of the thing...it is more amazing to me from the outside than inside! You will have the view over ther entire Palintine Hill as well This can take 1/2 to hour depending on whether or not you walk around it or how many photos you take. Then take your time at the Vatican which is far more interesting.

...go to see the Colosseum but do not enter....I visited it in late
Sept. early Oct. 2016 and honestly, without taking the under ground
tour which seems to thrill people, you could get bored in about 10
minutes.

JJ, sorry but I have to disagree with this. Most people do NOT get "bored in about 10 minutes." It's well worth seeing the interior even if one doesn't do the underground. My favorite in Rome? No, but neither would I suggest that someone go sit in a cafe and just look at the outside. A little reading in advance is helpful; just a couple of places to start:

http://www.bbc.co.uk/history/ancient/romans/colosseum_01.shtml

http://www.smithsonianmag.com/history/secrets-of-the-colosseum-75827047/

This is a suggestion board...I gave my opinion about a short trip to Rome, given the lines etc. and person's desire to see other things.Trying to pack in too much and feeling under pressure to tick off sights can put people on such tight schedules that they don't even stop to smell the roses.

Yes, it is a suggestion board and it's great to have a range of opinions My response may have sounded more harsh than intended so I'm very sorry if you took offense; you are absolutely entitled to your weigh-in!

I will admit, though, that yours is the first post I've even seen which has suggested that the interior should be skipped because a visitor might be "bored". It's just not a word I've seen applied to that particular attraction, either inside or out, unless a tourist is not interested in its history at all.