The cruises you can take without a passport, and when you still need one

• U.S. citizens can travel on certain "closed-loop" cruises without a passport.
• Closed-loop cruises are voyages that begin and end at the same U.S. port.
• Travelers without a passport will need other proof of citizenship, such as a birth certificate and government-issued photo ID.

There are some items that are staples of any cruise vacation packing lists, from sunscreen to swimsuits to a passport.

You may not need that last one, though. 

In some cases, passengers can embark without a passport – even on a cruise that visits other countries. That means guests who don’t have one – or who waited a little too long to renew – can set sail anyway.

“Travelers don't necessarily need a passport for all cruises,” said Sally French, NerdWallet Travel Expert and co-host of the “Smart Travel” podcast. “U.S. citizens can sail on certain ‘closed-loop’ cruises without a passport.”

However, it might still be worth bringing one. Here’s what travelers should know.

What is a closed-loop cruise?

Closed-loop cruises are those that start and end at the same U.S. port and sail in the Western Hemisphere, according to Customs and Border Protection. “For instance, if you board a cruise ship at Fort Lauderdale, Florida, and after visiting at least one foreign port of call, such as Bermuda, or Cancun, and return to Fort Lauderdale, you have taken a closed loop cruise,” the agency’s website said.

In place of a passport, U.S. citizens can leave and re-enter the country with other proof of citizenship. Those include Enhanced Driver’s Licenses or a birth certificate and – if they are 16 and up – a government-issued photo ID. The birth certificate must also be issued by the government. 

“An U.S. citizen under the age of 16 will be able to present either an original, notarized or certified copy of his or her birth certificate, a Consular Report of Birth Abroad issued by Department of State, (DOS) and/or Certificate of Naturalization issued by U.S. Citizenship and Immigration Services (USCIS),” CBP added.

American travelers also generally don’t need a passport for domestic river cruises.

Should I bring a passport on a closed-loop cruise?

Maybe. 

French noted that policies can vary by destination and cruise line. Regent Seven Seas Cruises, for example, requires all guests to carry a passport regardless of a voyage’s ports, according to its website.

Traveling without a passport can also complicate the embarkation process, leaving guests stuck in extra lines.

“I had a friend who forgot her passport for a closed-loop cruise, but she did have her driver's license and birth certificate with her,” French said in an email. “However, she was adopted, and her legal name was different from the name on her birth certificate. What should have been a simple check-in turned into a stressful ordeal at the port. She ultimately made it onto the ship, but not without a lot of anxiety and scrambling to provide additional documentation.”

Passengers will also need a passport if they need to fly home from abroad due to a medical emergency or to meet the ship at its next stop after missing an all-aboard time. The State Department “strongly” encourages cruise guests to have a passport book even if they are permitted to sail without one, per its website.

“The peace of mind alone makes getting a passport worthwhile, even if it's technically optional for your specific cruise,” French said.

Nathan Diller is a consumer travel reporter for USA TODAY based in Nashville. You can reach him at [email protected].