Q: I will be sailing on a Celebrity Cruise and arriving in Barcelona. I know there are lockers at Barcelona airport, but are there lockers or anything similar at the port where we would be able to store our luggage, while we walk around and see the city prior to having to board the ship?

A: There are no luggage storage facilities at the Cruise Terminals. Previously there were luggage storage facilities at Franca Station but they have closed this service down. Therefore where you leave your luggage now depends on what your plans are. Since you intend to return back to the ship then it is probably best you consider the nearest locker storage facility which is  Locker Barcelona . They are based in the centre of Barcelona 1 block from Placa Catalunya.  

For more information on the Locker Barcelona service see this page:
Locker Barcelona

You also have  Sants Estacio (Barcelona Sants Rail Station) which has a good left luggage facility.   If you are heading to Barcelona Airport after your visit to the town centre then you can also catch the train from Sants Estacio station directly to Barcelona Airport and Vice Versa.

For more information on luggage storage in Barcelona please visit the following pages:

Baggage Storage in Barcelona
Storage of Large Items
Barcelona Transport Station Maps

Map Showing the Locations of Barcelona Sants (Estacio Sants) and Barcelona Nord (bus station) which have luggage storage facilities. These two luggage storage facilities are the closest facilities for storing baggage to the Cruise Terminals.