Most cruise lines operate on a cashless basis. This means that when you get a drink at the bar, buy photos or snacks in the theater, you will present the crew member with your room key, which will also act as your room charge card onboard. Any onboard credits that you may have received from the cruise line or your travel agent will be on your onboard account when you arrive onboard. This will act as a credit against anything you charge back to your room.
Exceptions to the cashless system would be the gift shops (many times you can just use a charge card there), the casinos (though you can also charge back to your room a set amount per day) and gratuities for room service, shore excursion drivers and operators.
If you are sharing your cabin with someone and you will each be paying separately for your onboard charges, you can each use your own credit card. This can be handled when you do online check in, sometimes at the port or at Guest Services once onboard. You can also pay with cash or travelers check. You will be given a credit limit and when you reach that limit, you will have to go to Guest Services or the Purser’s desk to apply more money to your account.
I recommend if you have multiple credit cards on your account that you make certain when you are being charged onboard that you present your card to the crew member. If not, the lead guest in the room will be charged more often than the correct person. We’ve seen that happen a couple times before. It is easy to get it straightened out, but that’s not what you want to be doing on vacation.
On some cruise lines, you can review your charges on screen on your stateroom TV. On others, you will need to go to the Guest Services to get a copy of the bill if you want to review it during the cruise.
If you have children in your room, you can put restrictions on their cards so they don’t charge for anything and everything onboard. In most cases you can only turn the charging privileges on or off. This is how Disney handles charging. Some cruise lines however, may allow you to put a spending limit on their card.