After 10.25 p.m. or 22.25 its best not to take the train from the Airport due to the extensive building work which takes place at that time. The Mon Bus is the best option which now leaves between Terminal B & C. Or you could take a taxi, which costs approximately EUR 50.
Also, after 22.25 trains do not stop at Paseo de Gracia returning to Sitges. You have to go to Plaza de Catalunya.
View Gay Sitges Guide’s Getting Here Section for further information.