There are taxes on casino winnings. All U.S. citizens must report casino winnings to the IRS regardless of where the winnings occur. If you win $1,200 or more or win a table game with odds of 300-to-1, the cruise line will issue a W-2G form. A copy of the form is sent to the IRS and another to the winner. Additionally, some cruise ship casinos will provide the option to have the taxes deducted from your winnings. Or, you can take the total amount and pay the taxes on your own.