The easiest way to reach Terrassa is on the FGC (Ferrocarrils de la Generalitat de Catalunya) suburban train line S1 from Plaça Catalunya in central Barcelona. Trains run every 10 minutes or so during the day, take about 50 minutes, and arrive at Terrassa Rambla station in the heart of the city. A second route via Sabadell is operated by Rodalies (line R4) and uses Estació del Nord; it is slightly less frequent.
By car, Terrassa is just off the C-58 motorway, about 30 minutes from Barcelona depending on traffic. Parking in the city centre is restricted; use one of the underground car parks. The closest airport is Barcelona-El Prat, about an hour by car or train via Plaça Catalunya.