Visa-exempt foreign nationals are expected to have an Electronic Travel Authorization (eTA) to fly to or transit through Canada. Exceptions include U.S. citizens, and travelers with a valid Canadian visa. Canadian citizens, including dual citizens, and Canadian permanent residents cannot apply for aneTA.
Note: Until September 29, 2016, travelers who do not have an eTA can board their flight, as long as they have appropriate travel documents, such as a valid passport. During this leniency period, border services officers can let travelers arriving without an eTA into the country, as long as they meet the other requirements to enter Canada. Find answers to your questions about the leniency period.