The nearest airport is Rijeka airport (timetable of arrivals, timetable of departures), located on the island of Krk, approximately 40 kilometers from Opatija. In connection with arrival of each scheduled flight at the Rijeka airport, there is an airport bus which leaves shortly after the arrival and drives to Opatija. The travel time from the airport to Opatija is 45 minutes, and the price is around 10€.
In vicinity there are also Pula (100 km), Trieste (110 km), Ljubljana (130 km), Zagreb (180 km) and Venice (220 km) airports.
The easiest way from Pula airport to Opatija is to get the airport shuttle bus to Pula and pick up a bus for Opatija. From Pula to Opatija there are plenty of buses troughout the year, the travel time is about 2 hours. Other possibility is to take a train to Rijeka. For more info please visit Pula info web page.
Trieste, Ljubljana, Zagreb and Venice airports are connected by bus and train to Rijeka, and from Rijeka there are frequent buses (bus line no. 32) to Opatija. The main bus station is located a few hundred metres directly east from train station. For more than one person, taking a taxi might be less expensive than taking a bus.
From Trieste to Rijeka there are several buses a day on this route, with a journey time of two to two and a half hours. The services are run by Croatian bus company Autotrans – you can find timetables on their site or on the Trieste Bus Station website.
Buses depart from the main bus station in Trieste, situated at Piazza della Liberta 11 (next to the main railway station).
To Rijeka one can also go by train, but that involves getting from Gorizia Central to Nova Gorica (best take a taxi). However, Nova Gorica is an intersting station, as the border between Italy and Slovenia runs right through the middle of the square in front of the terminal building. See http://www.bahn.de for schedules.
In case of arrival to the Venice airport, one can go by train from Venice to Trieste in roughly two hours.
From Ljubljana to Rijeka there are two train connections a day. Please visit http://www.bahn.de for schedules.
From Zagreb to Opatija there are frequent buses, and one can also travel by train. Information about the bus connection can be found here, and see http://www.bahn.de for train schedules.