Originally Posted by
xliioper
Yes, you must go through customs pre-clearance at YVR in order to get to pre-clearance area for Canada-US flights. There's no short-cuts for transit passengers.
Ok that's what I thought. I've flown out of YVR to the states many times, and also flown out of SEA many times, but never YVR --> SEA (and connecting in SEA to an international flight). Wasn't sure if transit passengers in SEA would be peeled off somehow.
Originally Posted by
flyerCO
Of course you go through US immigration. You're entering the US.
I've flown through Heathrow many times connecting on to the EU, and in this situation you do not go through UK immigration simply because you've landed in the UK.