For all months except August (when the Vatican offices are closed), tickets are required for Papal Masses. TICKETS ARE ALWAYS FREE.
There are different types of tickets available depending on whether you are a dignitary, bishop, abbot, religious superior, priest, lay person, etc. Different types of attendees may be seated in different areas to assist with logistics.
If you need less than 6 tickets then you can simply ask the Swiss Guards for some. They have a stash of tickets explicitly for pilgrims who ask for them without a reservation. The Swiss Guard stationed at the Bronze Door (just to the left of the metal detectors of St Peters and then first right) have some to give out, as do the Swiss Guard at Porta Anna.
However, please note that the Swiss Guard will only have tickets for the Papal Mass the day before the event. Tickets will be given out from 3pm until 7pm the day before the scheduled Audience, and from 7am on the day.
For groups greater than 6, or if you wish to reserve your tickets in advance, you have 3 options.
For those attending events that are likely to be very popular, such as Midnight Mass or the Easter Mass, then you should attempt to reserve your tickets between 2 and 6 months before the Mass is scheduled to take place. The smaller the number of tickets requested the higher the chance of having your request granted so we suggest don't book extra tickets unnecessarily.
Tickets DO NOT necessarily guarantee entrance or a seat. When the church / square is full access will be denied even with your ticket. Only your arrival time with a ticket will guarantee your access so come early.
TICKETS FOR THE PAPAL MASS ARE ALWAYS FREE.