The NCL policy for Casinos are as follows: You have to be 18 years old or older (and have a valid ID) to gamble or be in the casino. No winnings will be paid to anyone or bets in violation of the age rule. In addition, you cannot take drinks or glassware out of the casino. You cannot bring cigars/pipes into the casino, but cigarette smoking is permitted. Slot winnings in excess of $1200 are subject to W2-G tax withholding.
The Carnival Cruises Casnio Policy states that you must be 18 and over to play in the casino. You can use your "Sail and Sign" card to buy coins and chips, and a handling charge of 3% will be added to all transactions.