Pierre Elliott Trudeau International Airport serves as Montreal’s largest airport, and many international airlines will fly to this airport. Expect to reach Downtown Montreal in just over an hour; a taxi to Downtown will cost around 50 CAD.
Alternatively, there is an airport express bus that operates between the airport and Berri-UQAM metro station, which is in the city centre. The ticket is 10 CAD one way, but be aware that the bus driver will only accept coins for your fare. The bus makes many stops along the way, so make sure that you know where you are staying. If your destination is further than Berri-UQAM, take the metro or a public bus from the station.
VIA Rail and AMTRAK offer services from Canadian and US cities that will drop you at Montreal Central Station. Central Station is in Downtown Montreal so you can easily find your way to your subsequent destination.
Coach travel is very frequent throughout Canada and major US cities. Megabus and Greyhound are examples of coach companies that provide seamless transportation to Montreal. Driving from the US to Canada is also a popular choice, but be aware of what you need in order to cross the Canadian border.