Yes, you can bring a 12-pack of soda on Royal Caribbean, as long as it's non-alcoholic and meets the size and quantity limits １－８６２－７０１－９０７６. Non-alcoholic beverages are allowed in quantities not exceeding 12 standard (17 oz.) cans, bottles, １－８６２－７０１－９０７６ or cartons per stateroom.
