Cruises are a popular way to travel and there are many options to choose from. Whether it's a tropical beach vacation, a river trip in Europe or a glacier cruise in Alaska, there's something enjoyable about kicking back on a ship, exploring a handful of ports and taking it easy for a few days.

The Caribbean is one of the most popular cruise destinations for U.S. travelers. But before you book a trip, knowing which travel documents are required and whether you need a passport is essential. For some destinations, you may not.

Do I need a passport for a Caribbean cruise?

In short, whether you need a passport depends on the cruise, including the start and end points, the ports you'll visit and your plans at those destinations.

More often than not, the answer is no. U.S. citizens don't need a passport if the cruise starts and ends in the same U.S. city. This is known as a "closed-loop" cruise.

That said, some may require a passport if you want to disembark at ports in any Caribbean destination. And if you're starting and ending your cruise at different ports within the U.S. — or flying in to or out of a Caribbean country — you will need a passport.

However, while many cruise lines may not require passengers to bring their passports, plenty recommend it, as does the U.S. Department of State. It can come in handy if you need an emergency medical evacuation or the ship has to schedule an emergency docking at a different port that's not on your itinerary.

So if you already have a passport, pack it anyway. However, it doesn't hurt to apply for one if you don't have one yet and have the time and funds.

What documents do I need if I don't have a passport?

If you choose not to carry a passport on a Caribbean cruise, here are the other documents accepted by the U.S. Customs and Border Protection for U.S. citizens traveling by sea for leisure purposes:

Passport Card.

Enhanced Driver's License.

Trusted Traveler Program card (NEXUS, SENTRI or FAST).

Form I-872 American Indian Card or Enhanced Tribal Card.

U.S. and Canadian citizens under 16 (or under 19 if traveling with a school, religious group or other youth groups) only need to present a birth certificate or another proof of citizenship.

On closed-loop cruises, a birth certificate and government-issued photo ID are all that's required.

Check with your cruise line before departure to see what documents are needed instead of a passport. Many require a state-issued ID and an original birth certificate if you don't have a passport.

While not related to an ID, it's also a good idea to consider purchasing travel or cruise-specific insurance before departing.

What Caribbean destinations don't require a passport?

If you're headed to one or more Caribbean countries on the list below on a closed-loop cruise, you aren't required to have a passport as a U.S. citizen.

Caribbean countries that don't require a U.S. passport for closed-loop cruises

Anguilla.

Antigua and Barbuda.

Aruba.

Bahamas.

Bermuda.

British Virgin Islands.

Cayman Islands.

Dominica.

Dominican Republic.

Grenada.

Jamaica.

Montserrat.

Netherlands Antilles.

St. Kitts and Nevis.

St. Lucia.

St. Vincent and the Grenadines.

Turks and Caicos.

However, other Caribbean countries may require a valid passport for closed-loop cruises if you plan to disembark, so verify this before your trip and ensure you travel with all necessary documentation.

How to obtain or renew a U.S. passport

Since it can be a good idea to pack your passport — even if it's not required — here's some vital information to keep in mind before traveling:

Apply for your passport at least a few months before your trip if you don't already have one. An application will take many weeks to process even if you pay for expedited service.

If you already have a passport, ensure it's valid for at least six months beyond your scheduled cruise and has at least two blank pages.

Check to see if you need visas for any scheduled ports of call, even if you don't plan to get off the ship.

You can renew a passport online or by mail, but you must apply in person at an approved location if this is a new passport.

Passport for a Caribbean cruise recapped

Do you need a passport to cruise to the Caribbean? While the answer is no in many cases, it's a good idea to bring it along, just in case.

It's accepted as legal identification, negates the need to bring multiple forms of ID and provides peace of mind if the worst should happen — such as flying home unexpectedly or docking elsewhere during your trip.

So, if you have the option, pack your passport and enjoy your cruise.