• From El Prat Airport, you get the AeroBus blue service, which goes from Terminal 1 and Terminal 2. It's under €6 to Catalunya Square and it'll only take 30 minutes. From there get on the Metro L3 line and head to Diagonal station.
• From Nord Bus Station, catch the number 39 bus. Get out in Rossello-Bruc then walk one block and you'll be at the Barcelona hostel.