Leonardo da Vinci–Fiumicino Airport: For Trastevere, skip the Leonardo Express to Termini: it is faster only if Termini is your destination. Take the FL1 regional train, direction Roma Tiburtina/Fara Sabina, directly to Roma Trastevere (about 27–35 minutes; roughly €8). From Trastevere station, use tram 8, bus H, or a short taxi for the old quarter. A fixed-fare airport taxi is sensible only with luggage or 2–4 people; confirm the official fixed fare before leaving the rank.
Ciampino International Airport: There is no rail station at the terminal. The least fiddly budget route is Trenitalia’s Ciampino AirLink: bus to Ciampino rail station plus train to Termini, about 40 minutes and roughly €3, then bus H or a taxi into Trastevere. For a late arrival or a group, use the official taxi rank rather than a pre-booked airport shuttle; Trastevere is within the central fixed-fare zone, but confirm the posted fare before departure.
Roma Termini: Termini is not convenient for Trastevere, despite being Rome’s main station. Take bus H toward Dei Capasso; it runs through the neighbourhood and normally takes 25–40 minutes in traffic on a standard city ticket. A taxi is often worth the extra cost with bags, but take one from the official rank, not an unsolicited driver.
Roma Tiburtina: Take an FL1 regional train toward Fiumicino Aeroporto and get off at Roma Trastevere, typically 35–45 minutes. This is much cleaner than crossing central Rome by metro and bus; check the departure board because not every regional service has the same stopping pattern.