There is an almost constant (and usually heated) discussion on social media on the need for passports when cruising, and most of the discussions are incorrect or wildly misleading. I have read them with amusement trending towards horror, because it is such a simple concept and most people miss one or both parts.

Here is the simple explanation from a non-lawyer: when someone enters the US (or any foreign country, for that matter), the visitor needs to prove two things to the local Immigration authorities – his or her citizenship and his or her identity. The document that almost always provides these two proofs is a passport, issued by the country where you are a citizen.

For a closed-loop cruise [only], the US State Department allows US citizens to prove identity with a drivers license and prove citizenship with an official birth certificate. This is why many of the loudest people on social media scream, “ALL YOU NEED IS A BIRTH CERTIFICATE FOR A CRUISE!” That is simply not correct. You also need a drivers license or State ID (not everyone has a drivers license.) Also, there are a multitude of cruises available that are not closed-loop. Finally, some cruise lines require passports (because it’s easier for them) and some foreign countries require passports.

Remember, a “birth certificate” is a birth certificate with a raised seal, issued by a government authority, not just a memento the hospital gave your Mom. A birth certificate can prove US citizenship. However, it cannot prove identity because there isn’t a photo.

A drivers license or some other State-issued photo ID will prove identity.

You need both documents because you have to prove your citizenship and identity. The names on the documents need to match. So, some people who change their names (marriage, for example) might also need the document that shows the name change.

A passport proves both citizenship and identity with one document and it’s a Federal document not a State.

The final piece of the puzzle is that the “birth certificate and drivers license” option works on a closed-loop cruise where none of the countries in the itinerary require a passport to enter. Not all cruises are closed-loop. Some countries (Canada) require passports no matter what. (Canada also looks at criminal records.)

As a side note – you enter the country when the ship enters its territorial waters (24 miles offshore or so, depending on laws and treaties), so “I’m just staying on the ship” is not a defense. If you’re on a ship in a Canadian port, you’re in Canada.

A closed-loop cruise departs from one port, wanders around and returns to the same port. So, if you’re sailing from Miami to Barcelona, you need a passport. Also, closed-loop requires that you depart and arrive on the same ship. If you miss the ship because you were at the bar or someone gets injured and stays behind for treatment, then you suddenly need a passport. (Air travel requires passports.)

The reality is that a passport allows you to cross borders on a cruise ship, a train, a bus or a plane (or any other conveyance.) Your birth certificate and drivers license works on a closed-loop cruise as long as there aren’t any problems.

The usual issue against passports is that “they’re so expensive!” A new passport for an adult is under $200 and is good for ten years. That’s $20 per year. The people complaining about prices are also paying $1000 per week for unlimited drinks. Priorities.

Bottom line: If all you are ever going to do is take closed-loop cruises from a port within driving distance of your home, and you are sure nothing will ever go wrong, then, technically, all you need is a birth certificate (citizenship) and a drivers license (identity.)

If you ever think you might venture out in the world beyond places that are a day’s sailing away from a US port or you have to fly to Mexico for a wedding or you want to have a contingency plan for emergencies, or you might just spring for that Transatlantic cruise someday, get a passport.

Here’s the US State Department’s information on cruise travel – see the rest of the site for generic travel information:

I’ve often considered the unspoken parts of the entire international travel issue, and I think what most people don’t realize is how much (I assume) the cruise lines do behind the scenes.

Think of the usual international travel scenario – I have to fly to Germany for a business meeting. When I leave the US, nobody cares – they just do security checks to make sure I’m not armed. The airline verifies that the name of the ticket matches my ID. The airline will also verify that I have documents that will allow me to deplane at the destination. However, when I land in Germany, German immigration wants to know who I am and where I came from – and that’s what a passport provides. When I come home, the Germans want to know I’m not armed, and not much else. When I arrive in the US, it’s the same thing – who are you and where do you come from? I show my passport, and I’m in. (Next, customs wants to know what I’m bringing home so they can charge duty, but that’s another discussion.)

When you are on a cruise, the cruise line provides governments with a manifest – a list of all the cruise passengers onboard – before they arrive in the country. They check everyone off the ship (you scan your key card and your photo displays for the security guards.) This creates a list of all the people who disembarked. When you get back on the ship, you scan your key card again, your photo comes up, and you are crossed off the disembarkation list.

Ship security knows at any time how many people left the ship and how many are still away. Since most port calls are a eight to ten hours or less, my assumption is that if a ship provides a list of passengers before arrival, and can tell immigration that everyone that disembarked returned to the ship before it sailed, the foreign country will take the money and run.

That’s the fundamental difference between cruising and travel. Many cruises are about visiting places, not delivering you to the places. So, everybody knows when you’re going to leave and it’s a really short time after you arrived.

When I got off the plane in Germany, that was one of the first questions asked – “When are you leaving?” It’s a bit rude, but then Immigration can put the date next to my passport number and know when to start looking for me.

With a cruise, they know when I’m leaving – when the ship sails. If I’m not on the ship when it sails, the ship will tell Immigration (and their port agent) to start looking for me.

If I’m not on the ship when it sails, I really need a passport.

In summary, a passport always works. A birth certificate and drivers license works in some very limited circumstances, for some limited cruises.