If one preclears U.S. Customs/Immigration in YYC, when the flight arrives in the U.S., is it necessary to exit and go through a security checkpoint once again before going to your connecting flight? U.S. arrival city is DFW, if that makes a difference.

As long as you don't have to exit the secure zone to change terminals -- nope, no new security. It's treated as a domestic flight.

-W

Thanks for the reply. I guess I was basing my concern on my experience with preclearing in DUB on flight to ORD. ALL pax have to exit ORD's Terminal 5, Concourse M and take a train to the other terminals for connecting flights, so the preclear doesn't help as much as it does at other airports.

If you pre-cleared US Immigrations and Customs at DUB you should have arrived into a domestic gate, unless you were on a carrier that uses ORD T5 (Aer Lingus ?).

I've pre-cleared at YYC several times and have always arrived into a domestic gate upon landing in the US (on AA @ DFW and DL @ SLC).

SDF

This was about 2 years ago and the carrier was AA. AFAIK, all AA flights from Europe/Asia arrive at ORD's T5 and you have to exit and use the train to get to the other terminals where you go through security again. I didn't take a survey, but there were many (all?) carriers using T5 for arriving foreign flights (maybe not from Canada?). In fact I had heard that part of the reason having to go through security again was that some of the pax flying through DUB, LHR, whatever, might have originated in some third world dump not having security as thorough as this country's (yeah, I know, but that's a can of worms I don't want to open in this thread ).

The answer has little to do with YYC. You'd best find someone that knows DFW well. But in general, a pre-screened flight arrives as a normal domestic flight would. So unless you are changing terminal etc it shouldn't be required.

You used to clear US immigration at DUB but not customs. Customs clearance came when you arrived in the US. I understand its both now so maybe that's changed.

You are correct. This applies to both Shannon and Dublin Airports, so when you arrive in the USA in UA (CO) you arrive as a domestic flight into EWR. It is great as you do not have to go through TSA abuse if you are connecting. Irish security is way more professional than the TSA.

All of DFW is connected airside by a train system, so unless your inbound flight gets routed through an international arrivals hall (which is shouldn't, since you're precleared), you should exit the aircraft into the the terminal airside and you can change terminals as needed.

Note if you check bags at a pre clearance airport, then even though your bags will be automatically loaded onto your connecting flight, the tsa will repeat the same inspection that catsa did in Canada. So on a tight connection, your bags are likely to misconnect. E.g. One hour connection YYC, den, cos won't work for bags.

That bag rescanning problem is soon disappearing, if it hasn't already. The US and Canadian governments signed a pact a few weeks ago and one of the issues that was agreed was that bags from one of the countries didn't need to be rescanned in the other country. The TSA and CATSA are conferring with each other and accepting each other's scanning practices as being adequate in their own country.

I recently flew YQR-ORD-MCO and my baggage tags had maple leaves along the edge, so I'm not sure if that means they weren't rescreened, but I had to go through US Customs as YQR does not have US preclearance.

I've flown YYZ-MCO, YYC-JFK, and YVR-DEN and in all three cases I arrived at a domestic terminal. If I had connecting flights (and I did in DEN) I could just wander to my gate.