From the Princess website...."Guests are also prohibited from bringing water, sodas and other non-alcoholic beverages on board that are packaged in bottles. A small quantity of non-alcoholic beverages (i.e., sparkling water, sodas, juice, milk) packaged in cans or cartons may be brought on board on embarkation day, only if carried on in Guests’ hand luggage (not in checked luggage). A small quantity is considered a maximum of 12 sealed, unopened cans/cartons of 12 ounces each or less per person."