Originally Posted by
dibby
If you`re a US citizen, there`s often a much shorter line in the US preclearance area specifically for US citizens and green card holders. I haven`t done preclearance in T3 lately, but it used to be there, and there is one in T1. Be certain to ask the uniformed personnel directing passengers when you enter the preclearance area. That can save a lot of time.
No longer is there a separate line (at least not in T3 in May 2008). But it only took 15 min (and that was with the line completely full, snaking back to the duty free shop). The concern with INT-US transfers at YYZ is with the Canadian immigration time (and the sometimes slow baggage reclaim process) and not with the US pre-clearance time (though that will disrupt tight schedules).