Cheap flights from St. Louis to Montreal from $175

The cheapest month to fly to Montreal from St. Louis is in August. Flight prices, which tend to average around $457, are often lower during this time because this is during the off-season. If you are unable to visit Montreal during the month of August, then departing from St. Louis during the month February is also very affordable. Most momondo users find prices during this month for around $506.

The cheapest day to depart from St. Louis to Montreal is on a Tuesday when prices can be found for as low as $959. Flights from St. Louis to Montreal on a Friday will generally be more expensive and average around $1,198. Keep in mind that these prices on both days could fluctuate depending on the season and the demand.

Our most recent data shows that the best time of day to fly to Montreal is in the morning. Flights from St. Louis to Montreal during this time can be as low as $997. At noon is when there is more demand to fly to Montreal, so prices are often more expensive at around $1,105 per ticket.

Fly from Lambert-St Louis to Montreal Pierre Elliott Trudeau Intl for the best Lambert-St Louis - Montreal flight prices

There are 4 cabin classes available to choose from on St. Louis to Montreal flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

You could potentially save up to 1% on your flight if you consider stops on a St. Louis to Montreal flight.

Detroit (DTW) was the most common stop: 50% of momondo users choosing 1-stop flights on this route connected there.

Flights via Toronto (YYZ) offer the lowest average round-trip price of $668.

Flights connecting via Detroit (DTW) have the shortest average one-way travel time: 4h 25m.

Detroit (DTW) has the shortest average layover time for this route: 1h 02m.

As of August 2026, 2 flights take off from St. Louis and land in Montreal each day. The most common flight departure time for this route is 12:00PM, with 100% of daily flights taking off in the afternoon.

As of August 2026, 14 flights take off from St. Louis and land in Montreal each week. The most common flight departure day for this route is Mon, with 14% of weekly flights taking off on this day.