Apple Pay is now available in Canada to customers of BMO (MasterCard, Interac), TD (Visa, Interac), Scotiabank (Visa, Amex, Interac) which are joining CIBC, Canadian Tire and RBC Credit which launched the service last month.
Apple Pay also extends to purchasing physical goods within apps or purchasing items from the Apple Store, while American Express is currently live and that won't change, support for all of the rest of the banks above will is also going live.
Launching payments within apps (all credit-card only; Interac support for in-app coming at a later date across these issuing banks)
Various Canadian apps have updated to be able to integrate Apple Pay for in-app purchases. For Apple Pay to work, users need an iPhone 6/6S, iPhone SE or an Apple Watch since these are the models that feature a secure enclave to enable the safe and secure transactions.
Source: Apple