If you come by public transport:

BUS: 17, 22, 58, 73, 75, 60, 196

Underground: L7 Avinguda Tibidabo

More info about public transport timetables and maps at http://www.tmb.net/en_US/home.jsp

Itineraries
From Campus del Mar by Bus and Underground
From Campus del Mar by Underground

From NH Rallye by Bus and Underground
From NH Rallye by Underground

From Penyafort-Montserrat by Bus
From Penyafort-Montserrat by Underground

From Residencia Torre Girona by Bus
From Residencia Torre Girona by Underground

From Residencia de Investigadores by Underground

Banne