While changing planes at YUL this week, I found that the exchange rates to obtain Canadian dollars using a US-origin ATM card were significantly worse inside the secure area of YUL. Three separate ATMs quoted costs of 81 cents US to buy 1 Canadian dollar + a $CDN 2.95 exchange charge (plus the $US1.50 my credit union charges for international transactions). After arrival at my final destination (Quebec), I used the same ATM card at a Scotia Bank ATM in the baggage claim area, and received Canadian dollars at a rate of 75 cents US to buy 1 Canadian dollar, including what ever exchange fee Scotia Bank charged for using their ATM. So buying 100 Canadian dollars inside YUL amounts to a fee of approximately $US9 when you include the exchange charge. I asked at the exchange bureau---they quoted the same rate of 81 cents per US dollar, but a $5.95 exchange fee. So wait until you get out of the secure area of the airport to obtain Canadian dollars.