Preclearance, also commonly known as pre-flight inspection, is offered by US Customs and Border Protection (CBP) at select locations around the world and allows US-bound passengers to undertake all immigration, customs, and agricultural inspections prior to boarding the flight outside the US.

How is preclearance different than the “normal” post-flight inspection upon arrival in the US?
A preclearance inspection is essentially the same inspection that travelers would undergo at a US port of entry. The only difference is that it is conducted outside the US. The advantage is that preclearance provides for domestic-style arrivals at US airports. Generally no additional immigration/customs forms will need to be completed upon arrival in the US.

Where are preclearance sites located?
There are many preclearance locations all around the world in such countries as Canada, Bahamas, Bermuda, Aruba, Ireland, and the United Arab Emirates (and possibly one day in the UK). These locations are based on agreements between the US and the host country, which allows CBP to staff officers at host airports and facilitate the customs and immigration process for passengers prior to arrival in the US.

What can I expect at a preclearance site?
This will vary slightly by location, but generally foreign nationals should do the following:

After checking in and going through airport security, go to the terminal where US Preclearance is located;
Fill out a CBP declaration form;
Present the CBP form with a passport, boarding pass, and visa (if applicable) along with supporting documentation (as necessary) to an inspecting CBP officer. The officer will ask a few questions and take fingerprints and a photo. If everything is in order, the officer will “admit” the traveler and provide an admission stamp in the passport.
Sometimes, if the CBP officer is not able to come to an immediate decision regarding admissibility to the US, travelers may be sent to a secondary inspection area for further questioning and/or documentation verification. I previously discussed secondary inspection in my post on deferred inspections.
After inspection, go through another security checkpoint—this time using US Transportation Security Administration (TSA) standards; and
Find departure gate!

I had the pleasure of personally experiencing US preclearance (albeit as an American citizen) when traveling back to the US from Aruba. While I had to ensure to arrive at the airport in Aruba well ahead of my flight, the process was generally stress free, and allowed a smoother and more efficient arrival upon landing back in the US, where wait times can sometimes be long and frustrating. Note that it’s very important to leave plenty of time for the preclearance process ahead of flight departure time. To help give travelers an idea of how much time they need to plan to spend going through preclearance at the airport, CBP has recently begun publishing helpful statistics on wait times based on day of the week and time of day at select airports, so far including Abu Dhabi, Toronto, and Vancouver.

For further guidance, US Preclearance in Dublin Airport, one of the largest preclearance sites, made a helpful video.

What are the advantages of using preclearance?
There are several advantages to using preclearance, but the two main advantages are 1) saving time; and 2) confirming foreign nationals’ admissibility to the US prior to boarding a flight to the US.

First, by using preclearance, travelers can save time upon arrival in the US. This is helpful for travelers who want to catch a connecting flight in the US or walk out of the airport quickly upon arrival to the US. This is especially true for foreign nationals who would normally encounter an extended delay upon arrival to the US due to a referral to secondary inspection.

A referral to secondary inspection can be routine in certain circumstances for verification of immigration status (e.g., foreign nationals who enter the US on advance parole with a pending adjustment of status or foreign nationals who processed their Green Cards at a US Embassy/Consulate abroad and are entering the US for the first time). Foreign nationals who know they will be put into secondary inspection can plan ahead to save time upon their arrival in the US by going through preclearance prior to boarding their flight (while, of course, allowing enough time for preclearance at the airport of departure).

Second, foreign nationals can receive a decision on their admissibility to the US prior to taking a flight to the US. This is especially important for foreign nationals who fear they may be referred to secondary inspection because their admissibility to the US is in question. While some referrals to secondary inspection are routine (see above), in other scenarios it can be cause for concern (e.g., foreign nationals attempting to enter the US on the Visa Waiver Program after spending a significant amount of time in the US, or foreign nationals who have previously been refused entry).

Being deemed admissible to the US through preclearance provides a valuable peace of mind for foreign nationals about to embark on a long flight to the US. Being deemed inadmissible through preclearance, however disappointing, saves foreign nationals from expending the time, money, and hassle of flying to the US only to be denied entry and then be required to fly back abroad. When admissibility to the US is in question, foreign nationals should consult with an experienced immigration attorney prior to entering the US, whether through preclearance or post-flight inspection.

Another circumstance where it can be advantageous to use preclearance is where foreign nationals are applying for non-immigrant status directly at the US port of entry (e.g., Canadian nationals applying for TN status). This will allow foreign nationals to receive approval prior to flying to the US, providing many of the same benefits described above.

It is important to note that while generally no additional immigration forms/inspections will be required upon arrival in the US, CBP does reserve the right to re-inspect travelers.

Tips From The Source
Earlier this year I had the pleasure of hearing Officer William Murray, Supervisor Gail Munson, and Dublin Area Port Director Guillermo Carattini speak via teleconference at the Rome District Chapter of the American Immigration Lawyers Association (AILA) conference in Athens, Greece. During this teleconference, the officers gave a few general tips and warnings about preclearance:

Preclearance is a great option for those who have Global Entry. Open to US citizens, lawful permanent residents (i.e. Green Card holders), Dutch citizens, South Korean citizens, and Mexican citizens (Canadian citizens and residents may enjoy Global Entry benefits through membership in the NEXUS program), Global Entry is a CBP program that allows certain travelers quick passage through immigration inspections and customs. Global Entry kiosks are available in many CBP preclearance facilities (including Shannon and Dublin airports), which allows many travelers to zip right through preclearance!
All foreign nationals who wish to enter the US on the Visa Waiver Program must have a valid Electronic System for Travel Authorization (ESTA) whether being inspected in preclearance or post-flight inspection. In addition, often, when a family of foreign nationals is going to the US for vacation on the Visa Waiver Program, frequently only one adult in the group has a valid ESTA because they assume it covers the whole family. This is not the case and causes a long delay in preclearance because each family member needs to complete and receive an approved ESTA in order to complete inspection. This can be prevented by completing the ESTA online for each family member at least seventy-two hours in advance of the flight to the US.
Foreign nationals with a criminal history should carry their final court disposition with them when traveling for easy accessibility in case any questions arise. Foreign nationals who anticipate any potential issue with their admission to the US should, again, consult with an experienced immigration attorney prior to entry to the US and also have their attorney’s name and phone number handy in case any questions arise during inspection.

Having operated preclearance offices beyond its borders since 1952, these operations have been highly successful and have expanded over the years. In Fiscal Year 2012, CBP officers and agriculture specialists precleared 15.6 million travelers destined to the US. Since that time, the US has continued to improve and expand its preclearance locations around the world. Bon voyage!