Vatican City and Colosseum

In order to climb up St Peter’s dome, you need to go through St Peter cathedral security check.
At the entrance to the basilica, after the security check, look right. There is a sign that directs you to the far right of the portico (past the Holy Door) and to the kiosk for the elevator.
This is where you purchase the tickets to St Peter’s dome. Note that the Basilica entrance is on the right side of the colonnade.*

The ticket to the Dome is a separate purchase from the Museum admission.

Trying to do the Colosseum and Vatican in one day is a monumental task.

Looking at your other posts its unclear just how long you will be in Italy and just how much and how many places you are trying to go. Are you sure you are not trying to do too much in too short of a visit?

I'm seeing such mixed posts on seeing the Vatican City and Colosseum
on our own purchasing skip the line tickets and downloading audio
guides.

Kathy, that's because travelers have different preferences for how they want to handle their sightseeing. Methods they choose can depend on different factors, such as time, budget, traveling with infants or young children, limited mobility, etc. Some folks like to move at their own speed with a guidebook or audioguide and others prefer guided tours. There's no wrong answer as long as it works for YOU.

Sightseeing independently with an audioguide or book is a good solution for the budget traveler and/or people like me who like to choose how long or not to spend on the various bits of an attraction. People strapped for time, however, might choose a tour to handle the tickets, provide instruction on where to meet and other necessary details, and a human guide to answer their questions along the way. There are also tours of different time lengths and depth of info dives, if that makes sense? The tourist with a deep interest in art might choose a tour that's very academic versus someone who might be overwhelmed with THAT amount of detail. :O)

But booking a tour or advance, timed-entry tickets for both the Colosseum and Vatican Museums is really essential for the time of year you'll be going. In fact, ALL advance tickets for the Colosseum are now timed-entry: the days of the pre-purchased "ordinary" ticket that allowed entry on any day/hour are a thing of the past. "Skip the line" also means just ticket lines: both of these attractions have security checkpoints that NO visitor can avoid, and can be long at the Colosseum.

Accessing St. Peter's directly from the Vatican Museums/Sistine via the interior shortcut - which eliminates having to go the long route outside and standing in another security-check queue - is only assured with a booked tour. Some independent tourists have reported being able to slide through that door but others have not so it's up to the whim of the guards on any given day.

One more little detail: the main routes through museums and the Sistine are epically crowded during high and shoulder seasons. A fair amount of posters have purchased "Early entrance" tours which get them into the Sistine and through some parts of the museums before the general public is allowed in. Most of them end up inside the basilica. They are a bit pricey but I don't believe I've ever heard anyone here say that they weren't worth every cent! We can recommend some good companies if interested.

So, it comes down to you: what kind of time you'll have; how comfortable you are making your own arrangements; how much your budget can handle; your sightseeing style; ages and abilities of your traveling companions; etc. What can you tell us that might be helpful?

the only tours I felt we really really needed guides for in Rome was the Vatican and the Colosseum and Roman Forum and I am so glad we did.

Kathy,

We just got back and because of an Italian holiday and a Sunday -- and our own travel schedule, we had to do the Colosseum and the Vatican on the same day. It was a long day, but not horrible. If you can do one each day, though, that's optimal. There were six of us - me and my wife, our three adult children and our daughter's beloved. Each person in the group commented how terrific the live guide for the Colosseum was.

I recommend a tour guide for the Colosseum for two reasons... It's a sprawling site if you see the arena, Palatine Hill and the Forum - and all are worth the singular effort. Our guide - besides being very informative - was also a very able navigator who skipped us through the lines at the arena and then guided us ably through the entire site. The second reason I recommend a guide is that you get immediate response to answers you may have.

We did the Colosseum in the morning - the tour met at, I think, 9:30 across from the Colosseum. And the Vatican in the afternoon. Our skip-the-line tickets were for 14:30.

If you do that, I recommend what we did... Have lunch right across the street from the Colosseum at one of a couple of touristy places. It wasn't our most memorable meal, but they move people through. The food was good enough, and we were ready for the Vatican. THEN take a cab from there to the Vatican. While you could walk, you'll be doing enough of that for the day. The cab gets you to the right spot (if you are also skipping the Vatican lines -- and I HEARTILY recommend that by buying tickets in advance) so you don't wander around wondering for the right place to be.

We used audio guides for the Vatican. Why? It enabled each of us to go at our own pace, and take time at the things that interested us without being obligated to the group. With the throngs, we absolutely got split up - all five of us. But each wound up enjoying the tour. Our oldest son found his way to the dome - and paid the extra euros for it when he was at the entrance to the dome, as I understand him. He was very, very pleased to have had that experience. Our youngest son passed entirely on St. Peter's and headed for beers. He was also very pleased.

Interestingly, our youngest sat through the audioguide's info about the Sistine Chapel, and then through Rick's audio tour. He liked Rick's way better - but enjoyed the Sistine Chapel, it seems, more than any of us others...

Speaking of St Peter's, Rick's guidebook suggests tagging along with a tour group to get the "secret" route to St. Peter's. When we were there in June, the guard at the exit to the Sistine Chapel was sending people over to the secret route... "Go to St. Peter's that way!" He practically admonished anyone who thought about leaving sooner. So, other than the fact that we waded through the Vatican Museums and the Chapel to get to St. Peter's, it was easy-peasy.

Have fun!