Trieste is served by the Ronchi dei Legionari Airport. Airlines that connect to Trieste include Alitalia, Ryanair, Lufthansa, JAT, AirDolomiti, Belleair.
Visitors can reach the ICTP campus either using Bus Line E51 (Airport Bus E51) or a taxi.
- From airport to ICTP by bus: The bus stops are outside the airport terminal building. Bus E51 (see schedule download at right) runs from the airport to Trieste and has a stop at Grignano (pronounced greenah'no) close to the ICTP campus and the Adriatico Guesthouse. The Adriatico Guesthouse is downhill from the bus stop and the other buildings are uphill. To reach the guesthouse, turn right down the small road "Via Junker"; the road eventually turns into a series of steps leading to the water's edge. The Adriatico Guesthouse is on the right. Check the campus map for exact directions. At the airport, bus tickets can be purchased at the Agenzia Turismo FVG on the ground floor or from the automatic machine at the arrivals hall. The current cost of bus tickets is: Airport-Grignano: Euro 3.25. Airport-Trieste Railway Station: Euro 4.00.
- From airport to ICTP by taxi: Taxis can be hailed outside the airport. To reach the Adriatico Guesthouse, provide the address: Via Grignano 9, Trieste; to reach the Galileo Guesthouse: Via Beirut 7, Trieste; to reach the Leonardo Da Vinci Building: Main Building, Strada Costiera 11, Trieste. The cost of a taxi from Ronchi Airport to the ICTP is around Euro 55, plus a small surcharge for each piece of luggage. The cost from Trieste Air Terminal (near central railway station) to the ICTP is approx. Euro 15. Please note that if, at the end of stay, a taxi is hired from a Guest House to the airport, the meter usually starts in Trieste city (from where the taxi is called) and stops at the airport. Thus, the cost is somewhat higher than the incoming journey.
- From Venice Marco Polo airport: Visitors can reach ICTP from Venice Marco Polo airport by bus and train (look at the trenitalia Website for train schedules). The Mestre-Venezia airport buses take approximately half an hour from the airport to the train station Venezia Mestre, where passengers switch to trains that run direct to Trieste. Train tickets must be validated at the validating machines before boarding trains; fines for carrying non-validated tickets are high.