See our St. Peter's Dome guide for what the climb itself involves — it's physically demanding, so factor that in regardless of how you book it.

What changes when it's bundled: the dome typically comes last, after the Basilica portion of the tour — the guide doesn't climb with you, since it's self-paced once inside. Confirm before booking whether the ticket is pre-arranged or something the group queues for separately; listings that look identical sometimes handle this differently.