Rome is a destination that rewards (and to some extent requires) advance trip planning.
Some popular attractions limit the number of visitors per day, so it's important to purchase tickets in advance as they can sell out.
Here's a list of tickets to book in advance:
Underground tour of the Colosseum
This tour visits the underground areas of the Colosseum where the gladiators waited to enter the arena, and where the animals and props were kept. Start checking for tickets here as soon as you know your dates in Rome--two months in advance is not too early. Tickets seem to become available in an unpredictable way--keep checking the site for updates.
The Vatican Necropolis, also known as the Scavi tour at St Peter’s
This tour, led by the Vatican Excavations Office, goes below St. Peter’s Basilica to visit the tomb of Saint Peter. Reserve your place by email here as soon as you know your dates (at least a month in advance). The reservation process requires you to list the dates you are available and the office will reply (generally within a few hours) with your assigned date and time, if space is available. Providing a number of date and tour language options, and having a small group size will increase your chance of getting a ticket.
Alternatively, you can join combine your Vatican tour with the Gardens and Sistine Chapel.
The papal audience is 90 minutes of prayers, readings and blessings with the Pope on Wednesday mornings in St. Peter’s Square (in good weather) or the Pope Paul VI Audience Hall near St Peter's (sometimes in December, January, and August). Tickets are not required for the August audiences. For free tickets at other times of the year, contact St Patrick's American Community in Rome 2 to 3 weeks in advance--this page also lists the dates on which there are no audiences. If you get tickets, arrive early (around 7am, the gates open between 7:30am and 8:30am) as seating is on a first-come basis.
If you miss out on tickets: There is standing room at the back of St. Peter’s Square for those without tickets--just keep in mind that your view may be poor or obstructed. There is another chance to see Pope Francis at the Sunday Angelus at noon in St. Peter’s Square. The Angelus is a 15-20 minute service that the Pope delivers from his apartment window. No tickets are required but, again, seating is on a first-come basis so arrive early.
One of my favourite galleries and often overlooked by first-time visitors to Rome, the Borghese houses an outstanding collection of paintings, sculpture and antiquities from the 15th to 18th centuries including "Daphne and Apollo" by Bernini and "Sacred and Profane Love" by Titian. Tickets are sold for a particular date and time and each visit is limited to 2 hours, after which you will be ushered out of the gallery. Arrive early as all bags must be checked and this process takes a while--you don't want to cut into your visit time. Book online (here) a couple weeks in advance--tickets can sometimes be available up to the last minute but there are also weeks when they sell out days in advance.
Now housing the French Embassy, the Palazzo Farnese contains the famous Farnese gallery with its fresco cycle depicting the loves of the gods by artist Annibale Carracci. Tickets should be booked online (here) at least a week in advance.
The Colosseum and the Vatican Museums are two attractions that don't require you to buy tickets in advance, but you may be able to reduce your time in line if you do: Short lines for sights in Rome, Italy
Tip: book your accommodation in Rome in advance as hotels can fill up quickly, particularly during high season! Read our Rome Accommodation Guide if you're looking for somewhere to stay while in Rome! We've also covered the top things to do in our Rome Activity Guide.
Travel Tip shared by Girl At Play