Question About St.Peter's Basilica

I'm not sure if this is what you are referring to but when I was there last year I found an area in the Basilica on the right hand side which is a private chapel like area. There is a guard there who will let you in and you can sit and take mass. As it is on the side it doesn't affect the flow of tourists in and out and no parts are off limits.

I think they actually do more than 5. We were there early in the morning...between 7:30 and 8:30 and there were 3 or 4 services going then. There are many side chapels. The services were in different languages and did not affect us as tourists except it made the experience even more awesome as we heard prayers and hymns in different languages as we walked through.

I found this information on "Trip Advisor" for you.
Mass is held at the following times at one of the chapels inside St. Peter's:
M-Sa: 9a, 10a, 11a, 12n, 5p
Sun: 9a, 10:30a, 11:30a, 12:10p, 1p, 4p, 5:30p
The mass will be in Italian. Hope this helps in your planning.
I saw a mass in one of the side chapels in Sept. They had a candle burning outside of the chapel, a person outside seeing that you were quiet and respectful if you went in. Hope this helps you. It does not conflict with the tourists in the rest of the Basilica.

Thanks for all of the info. I was asking about the masses so I could plan for a full and uninterrupted tour of St. Peter’s. I didn’t want to hear an announcement to exit the church in the middle of my dome climb. Services in the side chapels wouldn’t seem to pose any problems.

The masses take place in the side chapels not in the main Basilica. It will not affect tourists trying to visit the Church.

What is occuring in the side chapel with guard is Eucharistic adoration, not Mass.

For the late afternoon Mass (the largest Mass on weekdays), the area around the Altar of the Chair (under the dove window) is closed off for the liturgy, although the rest of the Basilica is open.