I often see posts in travel Facebook groups that ask about tight connections and whether they will have to go through “customs” on the connection. I think there’s a general confusion about the two step process for entering a country which consists of immigration then customs. I’m going to try and explain this from a traveler’s perspective.

Immigration is the thing you need to be most concerned with when it comes to traveling internationally or returning to the US. It is the process of how you enter or exit a country either through an interaction with an immigration officer or an automated passport check.

Customs is concerned with what items you are bringing into a country. It almost always involves walking through an exit after baggage claim with “Nothing to Declare.”

For example, when you have a connecting flight on one itinerary (one single ticket) from the US to an international destination, you will almost always go through immigration at your final point of arrival. In other words, if you fly Atlanta-Paris-Barcelona, you will go through immigration at Barcelona. The same applies if you have a New York-Doha-Maldives itinerary. However, if you have a domestic flight to reach your final destination, you will likely go through immigration at the international arrival point. For example, last year I flew JFK-London-Manchester and went through the automated immigration checkpoint at Heathrow before being allowed to board my flight to Manchester. When I arrived in Manchester, I was on a domestic flight and just walked out of the airport exit without anyone checking my passport. In most cases, even if you have a domestic connection at the end of your trip, you can check your bags all the way through and collect them at your final destination.

Even if you don’t have to go through immigration on your connection, you will likely still have to go through transit security. Usually, this is a separate security area just for transit passengers and is fairly quick. In some cases, if you switch terminals (like I did recently in Heathrow and Haneda), you will just go through the regular security checkpoint, so be sure to have enough transit time for this.

Flying back to the US is different. If you have a domestic (or international) flight after you touch down in the US, even if its on the same itinerary, you will have to go through immigration, collect your checked bags, walk through customs and then essentially behave as if you are starting your travels again (check-in, check bags, go through security, etc.). Most US airports have a decent process for this, but some may require a terminal change or other speed bumps along the way (JFK, Chicago O’Hare and Miami come to mind), so again make sure you have enough transit time in your itinerary.

If you are returning from overseas with a connection prior to your US-bound flight, you may have to go through a passport check at your connection point which essentially serves as exit immigration. For example, Rome-Paris-Atlanta will require a passport check in Paris even though it’s just a connection point. It’s likely that the destination country is requiring these countries and regions to have a final check before allowing people to board their international flight.

Another potential wrinkle when flying back to the US is preclearance. Many overseas airports now have US Immigration and Customs facilities onsite to allow your US-bound flight to operate like a domestic flight. This includes most major Canadian airports, many Caribbean airports, Dubai, Dublin, Abu Dhabi and others. Personally, I don’t love this as Global Entry allows us to speed through entry on arrival in the US anyway and limiting us to the preclearance terminal in the departure airport often eliminates interesting lounge options. However, for most travelers, it’s a great benefit as they do not have to wait in a long immigration line at their US destination.

When you travel abroad, it’s important to verify the entry or transit requirements. Before you fly anywhere internationally, you should verify whether you will need a visa to enter your final destination (or anywhere else you might visit on your trip while overseas). If you hold multiple passports, you also should check whether one of them might allow you to enter without a visa. For example, on our recent trip to Vietnam, I was able to enter visa-free for up to 15 days with my British passport, even though I used my US passport to enter Singapore and Cambodia on the same trip. Not only did that save the visa fee, but it also limited potential issues with visa processing or making mistakes on the online form.

Many countries now have e-visas that allow you to apply and receive your visa electronically prior to your trip. Be careful of time limits when you apply. For example, you might only be able to receive a 90 day window to use your visa so don’t apply 120 days before your trip. But don’t apply too late and sweat over getting it approved in time. I usually find that 2-3 weeks before the trip is a good window in case of any issues.

Some countries still allow you to get a visa on arrival, which means making sure you have the right amount of cash (if they don’t take a credit card) and getting in the right line when you arrive. Sometimes there’s a choice of e-visa or visa on arrival. Even if, in some cases, the e-visa costs a bit more than a visa on arrival, I prefer to pay that extra amount for peace of mind and skipping the line when we arrive.

So, when people ask “do I have to go through customs when I connect in Paris?” they are asking the wrong question. What they really mean is “do I have to go through immigration when I connect in Paris?” and the answer is no, but you still need time to go through security and potentially to switch terminals. Make sure you understand the difference between immigration and customs and make sure you understand the transit process wherever you are connecting before you go.

If you have questions about this post, let me know in the comments or send me an email at emptynestermiles@gmail.com. If you are thinking about opening a new credit card, please use one of my links.