We may send fewer letters than we used to in our everyday lives, but when we're on holiday it's still nice to send a postcard or a letter home.
Like many of the Italian public services, Italy's postal system is a source of despair among Italians and visitors alike: everybody in Rome seems to have stories of post arriving late or packages disappearing altogether.
In our experience, things aren't always that bad: regular letters and postcards do seem to arrive most of the time. Just don't send anything valuable.
Post Offices in Rome
The post offices in Rome, and Italy in general, are there mostly for paying bills, sending packages, and running basic bank account services. There are many post offices around the city, but if you're here on holiday, you shouldn't need to visit one: strangely enough, Italian post offices aren't actually a great place to buy stamps. They regularly run out of stock of any but the most common stamps, and even these are sometimes in short supply. Instead, get your stamps at a tobacconist (see below).
Where to actually buy stamps & post letters
Stamps for postcards and small letters are sold in tobacconists, wherever you see a sign with a big white 'T'.
The equivalent to airmail in Italy is now called Postamail Internazionale (which replaces the old Posta Prioritaria). As of July 2016, sending a postcard (up to 20g) by Postamail Internazionale to Europe cost €1, €2.20 to most of the rest of the word, and €2.90 to Oceania. (This is roughly the same as the last set of prices for posta prioritaria.) Prices rise sharply from there: see the full tariff at the Italian postal service's website poste.it (in Italian).
There is also a new service called, confusingly, Postapriority Internazionale, which offers faster delivery times, and tracking as far as the international sorting office. Prices for this start at €3.50 for a 50g letter within Europe. See full prices for Postapriority Internazionale here.
Italian postboxes are red, and fixed onto the wall near most tobacconists. They have two slots: one is for Rome and the area around the city; the other is for national and international post.
Fermoposta (Italian for poste restante)
One service that many Italian post offices do provide is poste restante, known in Italy as fermoposta. If you need to have something delivered to you, you can get it send to a post office for you to collect. There's information about fermoposta at poste.it (in Italian). Websites go out of date, so double-check with your chosen post office before getting anything sent there, as you're unlikely to be able to retrieve anything that's been sent to the wrong place.
You'll need to collect your post within 30 days, or it will be returned to sender. Don't forget to take ID with you.
The Vatican post office & special stamps
If you happen to be in the area around the Vatican City, or plan to go there during your trip, one alternative to the Italian postal system is to use the Vatican post office.
Prices for stamps at the Vatican are the same as the Italian system, but they have a reputation for being faster and more reliable. They also use their own stamp designs, which are a novelty and sometimes quite collectable.
Opening hours for the Vatican post office are on their website vaticanstate.va (in Italian, though most of the site is in English). Sadly, the Vatican's own fermoposta service is only available to residents of the Holy See, so while God will happily deliver your postcards, he won't look after your incoming mail for you.