QUOTE=FireFlyer;9799876]Yes, that's plenty of time for SLC. You will find lots of posts here about short SLC connect times. I routinely connect there with connections as brief as 30 minutes with no problem at all. Early morning flights are better, because the inevitable delays of the day haven't had the chance to set in yet.

42 minutes shouldn't be any problem at all.[/QUOTE]




QUESTION IS -------- Will OP clear US customs & immigration in Calgary OR at SLC ?

While this is a connecting flight, OP is in the unique position of
departing Canada, transiting US territory for a connection to Mexico...

my suggestion would be the at least BE PREPARED just in case of a misconnect.

These days flights WILL NOT wait at the gate for last minute passengers.

Good Luck and Safe travel. Mexico is NOT the ideal place for U.S. and Canadians to visit anymore with kidnappings, muggings rape and other crimes, including murder in these "tourist-trap fire-trap resort towns". Better off to head to the Carribean where they have a better sense of right and wrong and where it's a lot SAFER.