You will need your passport and receipts for any duty-free goods you have bought, in case you get stopped at customs. Normally, the ship will have been cleared by the local immigration authorities, but you may still be required to show a passport to officials when you disembark.
If you have already checked in for your flight and feel happier with a paper boarding pass, you can print this out in the ship’s internet center. If you’ve parked your car at the port, make sure you have the receipt and know where it is.
You will also need your SeaPass key card to leave the ship for one last time.