It's important to have all your personal and travel documents safe and secure when you cruise. How you choose to organize your plane tickets, passports, identification cards and cruise documents is up to you. What's important is that you have backups for all of these items. Before you leave, make two sets of photocopies of the following:
Once you have your copies, split them up into two separate Ziploc bags to make sure they stay dry. Put one set in your carry-on bag and leave the other at home with a trustworthy friend or relative. This way, you have a backup with you and one that can be sent to you if your documents get lost. Save all of your cruise receipts and keep them in the plastic bag. Compare your final charges against the receipts to make sure all the charges are legit.