San Juan is a strange beast. Last time I went you could buy liquor in the terminal and carry it on "as long as the Carnival folks didn't see it". I questioned this and was told that the security personnel doing the carry on screening were San Juan port employees and not Carnival employees... so the did not look for liquor. I suppose this was the land of Rum's response to the cruise lines banning of carry on alcohol. I am sure their sales dropped when people could no longer take it back to the ship and enjoy it AND the airlines stopped letting you bring it on the plane. As far as if that situation has changed, I can't tell you. I would wait until I got there and ask the liquor store personal what the status is. If they say its still as I describe above, then you can choose what you wish to do. I would not expect you to be able to get it past Carnival security in checked bags.
yes, you can carry on your luggage if you want.. but I would not advise it if you get there before 2 PM. Most of the time the cabins are not accessible until then and you would be dragging ALL of your luggage around the ship with you.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007