Ticket buying availability seems to be difficult to determine, at least as far as I can tell from looking at random dates on the official Vatican Museums Website, and various ticket types. You may need to just check the official Website - often. As of right now, you can still get in a few days in June - with a catch. And while basic tickets are sold out for August 11, and available for August 12 and 13, they’re not even being offered yet for August 16 exactly 2 months from today.
I’ve spent a good amount of time yesterday and today trying to determine which tickets to get for our upcoming September visit, and when to order them. I wonder whether third-party tour organizers, and there appear to be several these days, might be snatching up a lot of tickets, as soon as they go for sale, to resell to their own customers? Rick Steves’ guidebook even mentions Hawkers swarming the Vatican with tickets for sale as a last resort to get in, plus tickets for sale at the Vatican TI in St. Peter’s Square, as well as a private pilgrimage tour company located nearby.
Currently the Museums offer a Prime Experience option, a VIP option, and breakfast and Happy Hour (!) also offered, with options to be there before the museums open to the public or after they’re closed, and private or group guides, in addition to audio guides, but those all appear to be offered on a different schedule from the €21 “regular” online timed-entry (aka skip the line) tickets.
As of a few hours ago (on June 15), there were still tickets available for the next day, June 16. But those were only for Spanish-language 2-hour tours at 2:30 PM. I see that even those are now sold out, as are most days in the next few weeks. Randomly checking another upcoming date, June 28, while the €21 entrances are sold out (like most dates in the next 2 months), you can still reserve an entry on June 28, but only with a tour in German, and only at 10:30am, for an additional €13, resulting in a €34 ticket. That includes earphones to hear your guide, with 24 other people in your group. I wonder, are people allowed to wander away from the group, forego the earphones, and just consider the €34 entry as the only available way to get in that day?
Fast forward to August. As for 2 months from now, August 14 & 15 the museums will be closed for the holiday. But exactly 2 months from today, August 16, they’re scheduled to be open. While the official Website is accepting purchases of tickets for the other admission options, the basic €21 tickets are still “Not Bookable,” according to the official Website. Check the Website frequently, and once the right tickets for you are available, but then immediately, before someone else snatches them up.
Nearby in the Rome area, the Borghese Gallery is a similar situation - tickets available only through July 31, and it’s been that way for several weeks. At some point, August and September reservations will be available, and will likely sell out very quickly.
Last, I wonder how many Vatican Museums visitors nowadays are interested in seeing anything other than the Sistine Chapel? Maybe it’s like the Louvre in Paris - lots of people seem to be there only to see the Mona Lisa, snap a selfie, and then get out of the museum!