When you fly into the United States and connect to another flight, you clear US immigration and customs at the first US airport you land at, not at your final destination. There you go through passport control, collect your checked bags in most cases, pass customs, drop the bags at a re-check belt, and usually go through TSA security again before your domestic flight. The main exception is preclearance: if you cleared US border checks at one of 16 airports abroad before boarding, you land like a domestic passenger and walk straight to your connection.
Why the first US airport
US Customs and Border Protection (CBP) inspects every traveler at the first port of entry into the country. Your connecting flight is a domestic flight, and domestic terminals have no border officers. So if you fly Rome to Charlotte to Denver, Charlotte is where you show your passport and where your bags are inspected, even though Denver is on your ticket.
What happens, step by step
- Passport control. Follow the signs for arrivals and immigration. US citizens and permanent residents have their own lines, and Global Entry members and Mobile Passport Control users have dedicated lanes. Most airports now use facial comparison to match you to your passport.
- Baggage claim. Collect your checked bags, even if they were tagged through to your final airport. Bags that are not collected do not get to your final destination.
- Customs. Declare food, plant and animal products, goods you are bringing in and large amounts of currency. You answer the declaration questions at a kiosk, in an app or to the officer, depending on the airport; the paper form 6059B still exists for those who need it.
- Bag re-check. Right after customs, look for your airline's connecting-bag drop. You leave the bag there; you do not check in again.
- TSA security. At most airports you go through security again, because you were screened abroad, not by TSA. US liquid rules apply here, so pack duty-free bottles into your suitcase before you re-check it. For duty-free liquids, TSA's only exception is a sealed, tamper-evident bag bought within 48 hours, with the receipt.
- Find your gate. Your connection may leave from a different terminal, so check the departure screens.
The exception for some bags: remote baggage screening
CBP has started a program called International Remote Baggage Screening. Officers review the X-ray images of checked bags taken at the foreign airport before the plane lands, so passengers on that flight can go to their connection without re-checking bags unless CBP refers a bag for inspection. It began with American Airlines' Sydney to Los Angeles flight in April 2025, and CBP said it would expand to other routes and airlines. You still clear immigration and customs yourself. Your airline will tell you if your flight is part of it; otherwise assume you collect your bags.
The big exception: preclearance
CBP has officers at 16 airports in six countries: Dublin and Shannon in Ireland, Aruba, Bermuda, Abu Dhabi, Nassau in the Bahamas, and Calgary, Toronto Pearson, Billy Bishop Toronto, Edmonton, Halifax, Montreal, Ottawa, Vancouver, Victoria and Winnipeg in Canada. If you fly from one of them, you clear immigration, customs and security there. On arrival in the US you skip CBP and TSA and go straight to your connection or the exit. CBP notes this lets travelers accept tighter connections in the US. Our US preclearance guide covers how to plan around it.
Speed it up: Global Entry and Mobile Passport Control
- Mobile Passport Control (MPC) is a free CBP app with no application or background check. You scan your passport once, then up to four hours before landing you take a selfie and answer the arrival questions, including your customs declaration. A group of up to 12 people can submit together. CBP lists it at 37 US international airports and 15 preclearance locations, for US citizens, permanent residents, Canadian visitors and returning ESTA travelers. You still speak to an officer, but in a shorter line.
- Global Entry is CBP's trusted traveler program. It needs an application, a background check and an interview, and a membership fee applies; check the current amount on cbp.gov. Members use their own lane and often skip the officer conversation. It also includes TSA PreCheck, which helps on the security step after customs. See our Global Entry vs TSA PreCheck comparison.
Neither speeds up baggage claim or the bag re-check, which is often where the time goes.
How much connection time you need
Airlines publish a minimum connection time for each airport, and an international-to-domestic connection always has a longer minimum than a domestic one because of the border steps. If your connecting flights are on one ticket, the airline will only sell you a connection that meets its minimum, and if you miss it because the first flight was late, the airline rebooks you. With separate tickets, you are on your own.
The minimum is the shortest time the airline thinks is possible, not a comfortable one. Allow more time when you arrive at a busy hub at peak hours, when you need to change terminals, or when you travel with children or a lot of luggage. Our layover guide goes through how long to allow, and our missed connection guide covers what to do if it goes wrong.
Common questions at the first airport
- Do I clear customs again at my final airport? No. Once you clear at the first US airport, the rest of the trip is domestic.
- What if my international flight stops in the US and continues on the same plane? You still clear at the first US stop, usually with your bags, and then board again.
- What should I declare? Fruit, meat, plants, seeds and soil, anything from a farm visit, goods over your duty-free exemption and currency above CBP's reporting threshold. If you are unsure, declare it: an item you declare that is not allowed is simply taken away, while an undeclared one can bring a penalty.
