No test, or vaccine certificate, are required by Montreal-Trudeau Airport when travelling internationally. It is important that travelers make sure to check the requirements of the country they are visiting.
We recommend that you contact your airline to find out more about their regulations, as well as the authorities at your final destination.
You can consult The International Air Transport Association (IATA) website for more information: https://www.iatatravelcentre.com/world.php