Olbia to Cagliari trains might be a good value for money solution: travelling in Italy by train is often rather cheap and faster than taking a bus indeed Trains leave from Olbia and arrive at Cagliari every about 2 hours on average. If travelling with Trenitalia, you need to know the Olbia to Cagliari train schedule: the first train leaves at 05:53, while the last ride is at 18:52. A Olbia to Cagliari train cost about 18.00 €. But how long is the train ride from Olbia to Cagliari? Your journey takes about 4 hours on average. Trenitalia offers 2 direct trains between these two cities. Thanks to Trenitalia, offers, you can save on your trip from Olbia to Cagliari and find low cost tickets starting from 18 €!