Booking a taxi to Barcelona airport versus the rank
The official rank at El Prat is well run and usually moves quickly. It backs up at predictable moments: mid-morning arrival banks, Sunday evenings, and whenever several long-haul flights land together. Booking ahead removes that risk entirely and fixes your driver in advance, at the same metered fare.
The El Prat airport supplement
Every taxi journey starting or ending at El Prat carries a fixed airport supplement set by the AMB, and journeys starting at the airport have a minimum fare. Both are built into the estimate you see before booking, so there is no surprise on the meter.
Cruise passengers and the port
For passengers connecting to a cruise, the run between El Prat and the Moll Adossat cruise terminal has its own fixed closed price set by the AMB, rather than running on the meter. Enter the cruise terminal as your destination and the estimate switches to that fixed price automatically.