GYB Travel highly recommends you carry a Passport Book for any and all international travel (including closed loop cruises). Passports need to be valid for 6 months after your return date. For more information about Passport applications, click HERE.
To learn if the country you will be visiting requires a visa or to learn of the latest travel warnings about that country, The Department of State travel website can help you find the answer you need.
The TSA website is another great source when traveling by air. Here you can find information about applying for the TSA Precheck program, latest information about carry-on regulations and some tips to make your trip through security go smooth.