We will be visiting Rome for just a few days. One day i planned to dedicate to colosseum and “walking tour” sights, and the other to the Vatican. We are there on Saturday and Sunday, so I was thinking that Vatican made more sense on a Sunday. Mass at St. Peter’s seems like an amazing experience! An comments on sunday mass at St. Peter’s? Do we need reservations or tickets? Are the museums and other sights (bell tower, etc) open as usual?
Saint Peter's basilica is free, but there is a security line that nobody can skip.
The only other area of the Vatican tourists can enter is the Vatican Museums (that includes the Sistine chapel). Being a Museum owned&managed by the Roman Catholic church it's closed 3 Sundays a month.
Tickets can be purchased in advance on the official site.
There are no "skip the line tickets". All tickets purchased in advance will let you skip the tickets line.