Passengers, citizens from visa exempted countries, wishing to entry Canada as visitors will be asked to present at check-in a return ticket to their country of origin or an onward ticket to another country within a maximum period of 6 months.
This is a mandatory requirement without which you may have your boarding denied.
Residents and/or passengers with Canadian nationality;
Passengers traveling with visa authorizing their stay beyond 6 months.
For more information please contact the nearest Canadian Embassy of your local of residence.