Originally Posted by YXUhomebase

unfortunately you have to go through security a second time at any Canadian airport when you land from USA and have a domestic connection.

The rule is set because in theory you have to pick up your checked bags when going through customs and in theory could transfer an items from checked to carry on.

It is frustrating - actually YVR in my opinion is the absolute worse.
Especially when you go through security in one airport fine and then in another they have to pull all your stuff out - same bag!

There is a domestic Nexus line in T1 at pearson but never have found it really worth it - it is on third floor. Second floor security is often faster.

I have done it in 20 min. from getting off plane, through Nexus Canadian customs, exiting baggage (no checked bags) then up stairs and through security and to domestic gate. But might be harder to do it faster than that!