If you don't land in Barcelona until the afternoon, you definitely need to plan an overnight stay before the first day of walking.  We recommend the Pension Ecozentric in Barcelona for this purpose.. This recently modernised guesthouse is very centrally located and very close to the train station towards Portbou.

The hotel and accommodation offer in Barcelona is quite expensive all year round, the Pension Ecozentric offers a very good price-performance ratio in our view.