When you fly internationally to the United States, you will typically clear customs and immigration after you arrive in the U.S. However, if you are flying non-stop to the U.S. from the following fifteen foreign airports, you will actually preclear customs and immigration before you board your flight to the U.S.:
- Calgary International Airport
- Edmonton International Airport
- Halifax Stanfield International Airport
- Montréal-Pierre Elliott Trudeau International Airport
- Ottawa MacDonald-Cartier International Airport
- Toronto Pearson International Airport
- Vancouver International Airport
- Winnipeg James Armstrong Richardson International Airport
- Queen Beatrix International Airport (Aruba)
- Grand Bahama International Airport (Freeport)
- Lynden Pindling International Airport (Nassau)
- Bermuda International Airport
- Dublin Airport
- Shannon Airport
- Abu Dhabi International Airport
From these airports the same immigration, customs, and agriculture inspections of international air passengers typically performed upon arrival in the U.S. are completed before departure.
The biggest advantage of preclearance is that when you arrive in the U.S. your flight is treated as a domestic flight, which means shorter connections are possible and you will usually be able to leave the airport faster in case you are arriving into your final destination.
On the flip side, the biggest downsides of preclearance are that you are forced to arrive a little earlier at your departing airport and that you might not be able to access all the airline lounges you would have otherwise been able to access. Another downside if you have Global Entry and are flying to the U.S. from Freeport and Bermuda, is that apparently neither airport has Global Entry kiosks yet. All other airport mentioned above have Global Entry kiosks, so you are still able to enjoy your GE privileges even if preclearing.
The Department of Homeland Security has already announced its intentions to expand preclearance to the following airports:
- Brussels Airport
- Punta Cana International Airport
- Narita International Airport
- Amsterdam Airport Schiphol
- Oslo Airport, Gardermoen
- Adolfo Suárez Madrid-Barajas Airport
- Stockholm Arlanda Airport
- Istanbul Ataturk Airport
- London Heathrow Airport
- Manchester Airport
Even though I have Global Entry, which means that I rarely spend any significant time going through customs and immigration, I like the concept of preclearance. Anything that will help me get home faster after a long international flight and/or expand my connecting options is OK in my books. The key is for DHS to manage preclearance efficiently and staff the program appropriately, which is apparently where they have failed in some locations.