The cathedral's own practical page, read on October 10, 2026, says time slots are generally released two days before, the day before and on the day itself, so there is nothing to book months ahead. It also warns that some agencies and guides resell these free slots at a price and that such tickets are worthless and will not get you in; use only the cathedral's site or app. Without a slot you may wait a long time at busy hours.
The cathedral is open Monday to Friday from 7:50 a.m. to 7:00 p.m., later on Thursday, and on Saturday and Sunday from 8:15 a.m. to 7:30 p.m., with last entry 30 minutes before closing. Mass is at 8:00 a.m., noon and 6:00 p.m. on weekdays; at 8:30 a.m. and noon on Saturday, with the anticipated Sunday Mass at 6:00 p.m.; and on Sunday at 8:30 a.m., 10:00 a.m. (Gregorian chant), 11:30 a.m. and 6:00 p.m. Confessions are heard Monday to Saturday from 10:00 a.m. to noon and 2:00 to 6:00 p.m., and on Sunday from 4:00 to 6:00 p.m.
Good to know before you go: for a pilgrim the calmest way in is to come for Mass and stay to pray afterward. Two things are separate from the free visit. The treasury charges an entry fee and keeps its own hours (9:30 a.m. to 6:00 p.m. Monday to Saturday, to 8:30 p.m. on Thursday, and 1:00 to 5:00 p.m. on Sunday), and the towers are booked only through the towers' own official website. The cathedral says the interior and the treasury are accessible to wheelchair users.