$143 Cheap Flights from St. Louis (STL) to Montreal (YUL)

View $143 flight on Wed, Oct 29, 2025Opens in a new window

Popular airlines from St. Louis Lambert Intl. Airport (STL) to Montreal–Trudeau Intl. Airport (YUL)

Cheap Flights from St. Louis to Montreal (STL-YUL)

Prices were available within the past 7 days and start at $143 for one-way flights and $348 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

American Airlines
Sat, Sep 20 - Tue, Sep 23
STL
St. Louis
YUL
Montreal
$348 Roundtrip, found 2 days ago
$348
Roundtrip
found 2 days ago
Select American Airlines flight, departing Sat, Sep 20 from St. Louis to Montreal, returning Tue, Sep 23, priced at $348 found 2 days ago
American Airlines
Thu, Oct 16 - Wed, Oct 22
STL
St. Louis
YUL
Montreal
$351 Roundtrip, found 21 hours ago
$351
Roundtrip
found 21 hours ago
Select American Airlines flight, departing Thu, Oct 16 from St. Louis to Montreal, returning Wed, Oct 22, priced at $351 found 21 hours ago
American Airlines
Thu, Oct 23 - Thu, Oct 30
STL
St. Louis
YUL
Montreal
$354 Roundtrip, found 22 hours ago
$354
Roundtrip
found 22 hours ago
Select American Airlines flight, departing Thu, Oct 23 from St. Louis to Montreal, returning Thu, Oct 30, priced at $354 found 22 hours ago
American Airlines
Thu, Oct 16 - Wed, Oct 22
STL
St. Louis
YUL
Montreal
$361 Roundtrip, found 21 hours ago
$361
Roundtrip
found 21 hours ago
Select American Airlines flight, departing Thu, Oct 16 from St. Louis to Montreal, returning Wed, Oct 22, priced at $361 found 21 hours ago
American Airlines
Wed, Sep 17 - Wed, Sep 24
STL
St. Louis
YUL
Montreal
$365 Roundtrip, found 5 days ago
$365
Roundtrip
found 5 days ago
Select American Airlines flight, departing Wed, Sep 17 from St. Louis to Montreal, returning Wed, Sep 24, priced at $365 found 5 days ago
American Airlines
Tue, Sep 16 - Tue, Sep 23
STL
St. Louis
YUL
Montreal
$378 Roundtrip, found 4 days ago
$378
Roundtrip
found 4 days ago
Select American Airlines flight, departing Tue, Sep 16 from St. Louis to Montreal, returning Tue, Sep 23, priced at $378 found 4 days ago
United
Tue, Nov 4 - Tue, Nov 11
STL
St. Louis
YUL
Montreal
$428 Roundtrip, found 1 day ago
$428
Roundtrip
found 1 day ago
Select United flight, departing Tue, Nov 4 from St. Louis to Montreal, returning Tue, Nov 11, priced at $428 found 1 day ago
Delta
Tue, Oct 21 - Tue, Oct 28
STL
St. Louis
YUL
Montreal
$489 Roundtrip, found 3 hours ago
$489
Roundtrip
found 3 hours ago
Select Delta flight, departing Tue, Oct 21 from St. Louis to Montreal, returning Tue, Oct 28, priced at $489 found 3 hours ago
Air Canada
Sun, Sep 28 - Sun, Oct 12
STL
St. Louis
YUL
Montreal
$508 Roundtrip, found 3 days ago
$508
Roundtrip
found 3 days ago
Select Air Canada flight, departing Sun, Sep 28 from St. Louis to Montreal, returning Sun, Oct 12, priced at $508 found 3 days ago
WestJet
Tue, Nov 25 - Sun, Dec 7
STL
St. Louis
YUL
Montreal
$748 Roundtrip, found 4 days ago
$748
Roundtrip
found 4 days ago
Select WestJet flight, departing Tue, Nov 25 from St. Louis to Montreal, returning Sun, Dec 7, priced at $748 found 4 days ago

Find the cheapest month to fly from St. Louis (STL) to Montreal (YUL)

August is typically the cheapest month to fly

From $340 - $936 per traveler.

Graph displaying average flight prices per month

Alternative airports near Montreal

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Pierre Elliott Trudeau Intl. YUL. Cheapest and Closest option available. Average driving time to city center is 17 minutes. Flights from $695
YUL
Pierre Elliott Trudeau Intl.
CheapestClosest
Average driving time to city center17 min
Flights from $695
Flights from St. Louis (STL) to Montreal (YUL)
Origin airport
Lambert-St. Louis Intl.
Destination airport
Pierre Elliott Trudeau Intl.
Airlines serving
Air Canada, American Airlines, Delta, United, WestJet
Roundtrip price
$348
Distance
967 mi
Average flight time
2 hours 30 mins

St. Louis to Montreal Flights

The cheapest times to fly from St. Louis to Montreal

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from St. Louis to Montreal are during the month of September. You can find some of the cheapest flights from St. Louis to Montreal with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from St. Louis to Montreal

Sunday is one of the best days to book for cheap flights from St. Louis to Montreal: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from St. Louis to Montreal

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from St. Louis to Montreal in 2025. You can also book with separate airlines for your outbound and return journeys, from $143 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap St. Louis to Montreal flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your St. Louis to Montreal airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Frequently asked questions

How much does a flight from Lambert-St. Louis Intl. Airport (STL) to Pierre Elliott Trudeau Intl. Airport (YUL) cost?
Cheap return flights from Lambert-St. Louis Intl. Airport (STL) to Pierre Elliott Trudeau Intl. Airport (YUL) start from $636. This information is based on the cheapest price found on Expedia for this return journey departing within the next three months. This airfare is for a Air Canada and United flight leaving STL on August 18 2025 and touching down at YUL. The price was last updated on July 23 2025 and has not changed since.
What is the cheapest month to fly from STL to YUL?
The cheapest flights from STL to YUL are usually during off-peak season, when demand is lower. To save money, avoid flying during public holidays, school breaks and major local events.
What is the cheapest airline that flies from STL to YUL?
With prices starting from $297 for a one-way journey from STL to YUL, Air Canada is currently the cheapest carrier for this route. This fare is based on the lowest price found on Expedia departing within the next three months. The flight takes off from STL on September 10 2025. Prices were last updated on July 23 2025 and have not changed since.
How many flights per day from Lambert-St. Louis Intl. Airport (STL) to Pierre Elliott Trudeau Intl. Airport (YUL)?
You'll need to book a flight with a layover if you're traveling from Lambert-St. Louis Intl. Airport (STL) to Pierre Elliott Trudeau Intl. Airport (YUL). Direct flights don't operate daily on this route. However, simply filter your search to include one or two stops to find the best option for your trip.
What day of the week has the most flights from STL to YUL?
Typically you'll find the largest variety of flight choices on a Friday. Tuesdays tend to be the quietest.* However, this can vary based on the season, airline and other factors.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What airline has the least delays from STL to YUL?
With 81% of journeys typically arriving as scheduled, Air Canada has the best on-time performance for nonstop flights from Lambert-St. Louis Intl. Airport (STL) to Pierre Elliott Trudeau Intl. Airport (YUL). To check your flight status and get notified if anything changes, use the Expedia App.
What is the best time to fly from Lambert-St. Louis Intl. Airport (STL) to Pierre Elliott Trudeau Intl. Airport (YUL)?
To touch down at Pierre Elliott Trudeau Intl. Airport (YUL) without delays, select a flight that leaves Lambert-St. Louis Intl. Airport (STL) before 3 PM. The chance of cancellations is 22% higher, on average, for departures after this hour.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
Is it cheaper to buy a plane ticket from Lambert-St. Louis Intl. Airport (STL) to Pierre Elliott Trudeau Intl. Airport (YUL) last-minute?
Holding off until right before your break to book your flight from STL to YUL often results in higher prices. While you may find some last-minute discounts, they aren't always guaranteed. Keep your travel plans flexible to maximize your chances of snagging a bargain.
Is it cheaper to book a STL to YUL flight and hotel package?
Booking a STL to YUL flight and hotel package is typically cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your trip in one place. Choose from our extensive range of stays and then add flights, car rentals and activities to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Lambert-St. Louis Intl. Airport (STL) to Pierre Elliott Trudeau Intl. Airport (YUL)?
It's generally possible to cancel or reschedule your STL to YUL flight. However, if the booking was made more than 24 hours ago, additional charges may apply. Check your airline's policies in your itinerary to see what changes are possible and whether any costs are involved. You'll also find more information on our Customer Service portal.

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*Available to One Key members.