This card is your room key so you must keep it on you at all times unless you want to get locked out of your room. Depending on the colour and the class listed on it, it will also determine if you are able to go into certain areas at certain times or do certain activities. The information on the front also determines what type of drink package you have included (or not included) so this is your life line on the ship.
When you are at the pier doing check in, this is when they connect your Sea Pass to the credit card that you are wanting them to charge at the end of the cruise. If you want to change the form of payment or pay in cash / traveller checks then you will heave to head down to the Guest Relations Desk where you will be given a form to fill out. They will then update your information and take your payments if you are going them right then and there. Side note: the printing on the card does rub off and the cards do demagnetize often so you will probably be back here. The first time we went down it was because the wrong drink package was on our card, hubby was down there every two days as his phone or pants would demagnetize it but I only had to go down to get my card reactivated once.
Since you are using a card that is not a credit card, pricing can add up fast without thinking about it (everything is charged in US and there are 18% gratuities added to all alcohol) so it is good to keep an eye on your bill. Your room TV allows you to pull up account information so you can go through it and call down to Guest Relations if there is anything that needs to be adjusted. Side note: if you have not pre-paid for your tips you can adjust the daily amount you are charged so if you feel that you are drinking a lot and want to reduce the overall tips you are paying that day then you can. Just keep in mind that these tips are shared between food outlets, your room cleaning staff, and pretty much everyone else you come in contact with day-to-day.
On the last day of the cruise, just like a hotel, a statement is supposed to be delivered to you so you know what you are being charged for. We didn't get one of these though but as we were not going to pay in cash nor change our card so we didn't have to worry about anything and just left the ship.
