a very popular destination for cruises in the mediterranean, my son has use and quite happy with it.
Out of Barcelona to the islands and even Rome ,Italy
you have in English all if not most questions you may have on the cruise port there at the contact link below
important to know the T3 PORTBUS shuttle takes cruise passengers from Plaza de Colón in central Barcelona to terminals A, B, C and D (Palacruceros) on the Adossat wharf.
and an even clearer site from unofficial sources but very well explained (better than I anyway) is here
a leading site on cruises here
and from Barcelona tourism board a full pdf file information on the cruise port here
finally a ferry booking site in Spanish but can be in many languages
We picked up a cross Atlantic cruise ship at the harbor. It was a 17 day cruise, and a few stops along the way; like Mallorca, Malaga, Canary Is, and Freeport Bahamas. This may be the way to go home once, but no more. Beside getting something replicating the Legionares Flu, we put up with very obese people, and a number of scooter chairs they get around the ship in.
The ship was new and could hold 4,000 passengers plus crew, but they did not expand the ship facilities very much, if at all, so the whole ship was more cramped than when there would be 2,000 passengers on board.