I booked a flight out of the Girona airport instead of the Barcelona airport. What is the best way to get from the cruise ship port in Barcelona to the Girona airport?
Your best bet is probably the bus service from Barcelona's North bus station (Estacio d'Autobusos Nord). Make sure you aim for the right one....there's a similar bus that goes to Girona city center as well, so make sure you're on the bus for the Girona airport. It's run by a private company, Sagales, but it coordinates with Ryanair and other discount airline departures and arrivals. You can check the latest schedule here. Check it just before you leave to get the latest info. The bus trip usually takes about 1 1/4 to 1 1/2 hours.
The best way would be to take a cab from the port to the bus station...probably about 20 Euro.
But you could also take the shuttle bus to the port entrance, find the Drassanes metro station just off the Christopher Columbus, take the Metro two stops to Placa Catalunya, then transfer to the L1 metro line (direction Fondo). Take that two stops to Arc de Triomf stop, and walk from there....maybe about 10 minutes to the bus station.
For the site of the bus station, go to maps.google.com and copy and paste in the following coordinates (41.394329, 2.182905). the Arc de Triomf metro station is down and to the left (to the southwest.) For taxi purposes, the bus station is a #80 Carrer d'Ali Bei.