Please bear in mind that generally the only taxis in Barcelona transported to 4 people, including children. If traveling over 4 is advisable to book their own transportation from the Barcelona airport private.

You can take your taxi at Barcelona Airport right in front of each terminal. Taxis operated by queue. Generally queues are fast but there can be delays during peak hours.

The approximate rates from the Barcelona airport on weekdays (Monday to Friday from 07.00 to 21.00) are: Plaza Spain, € 14.90; to Plaza Catalunya € 17.20; Sagrada Familia to € 20.60.

Prices approximate Saturdays, holidays and nights (from 21.00 to 7.00): Plaza Spain € 17.80; Plaça Catalunya € 20.60; Sagrada Familia to € 24.50.

These rates include the supplement to the airport. The supplement baggage is € 0.90 for each. The amount payable is indicated on the meter, and you may want to call the bill.

If you need more information about taxis at Barcelona Airport
http://barcelona.airport-shuttle.com