$210 Cheap Flights from Montreal (YUL) to St. Louis (STL)

View $210 flight on Wed, May 21, 2025Opens in a new window

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Find available prices by choosing your travel dates.

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

Prices were available within the past 7 days and start at $210 for one-way flights and $405 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

American Airlines
Thu, Jun 5 - Mon, Aug 18
YUL
Montreal
STL
St. Louis
$405 Roundtrip, found 4 days ago
$405
Roundtrip
found 4 days ago
Select American Airlines flight, departing Thu, Jun 5 from Montreal to St. Louis, returning Mon, Aug 18, priced at $405 found 4 days ago
Delta
Tue, May 13 - Wed, May 14
YUL
Montreal
STL
St. Louis
$416 Roundtrip, found 1 day ago
$416
Roundtrip
found 1 day ago
Select Delta flight, departing Tue, May 13 from Montreal to St. Louis, returning Wed, May 14, priced at $416 found 1 day ago
United
Wed, Aug 6 - Sun, Aug 31
YUL
Montreal
STL
St. Louis
$421 Roundtrip, found 5 days ago
$421
Roundtrip
found 5 days ago
Select United flight, departing Wed, Aug 6 from Montreal to St. Louis, returning Sun, Aug 31, priced at $421 found 5 days ago
Air Canada
Sun, May 4 - Sun, May 11
YUL
Montreal
STL
St. Louis
$422 Roundtrip, found 3 days ago
$422
Roundtrip
found 3 days ago
Select Air Canada flight, departing Sun, May 4 from Montreal to St. Louis, returning Sun, May 11, priced at $422 found 3 days ago
American Airlines
Sat, Jul 19 - Thu, Aug 28
YUL
Montreal
STL
St. Louis
$425 Roundtrip, found 5 days ago
$425
Roundtrip
found 5 days ago
Select American Airlines flight, departing Sat, Jul 19 from Montreal to St. Louis, returning Thu, Aug 28, priced at $425 found 5 days ago
American Airlines
Wed, May 7 - Tue, May 13
YUL
Montreal
STL
St. Louis
$426 Roundtrip, found 3 days ago
$426
Roundtrip
found 3 days ago
Select American Airlines flight, departing Wed, May 7 from Montreal to St. Louis, returning Tue, May 13, priced at $426 found 3 days ago
United
Fri, Aug 15 - Mon, Aug 18
YUL
Montreal
STL
St. Louis
$430 Roundtrip, found 6 days ago
$430
Roundtrip
found 6 days ago
Select United flight, departing Fri, Aug 15 from Montreal to St. Louis, returning Mon, Aug 18, priced at $430 found 6 days ago
United
Sun, May 4 - Wed, May 14
YUL
Montreal
STL
St. Louis
$431 Roundtrip, found 3 days ago
$431
Roundtrip
found 3 days ago
Select United flight, departing Sun, May 4 from Montreal to St. Louis, returning Wed, May 14, priced at $431 found 3 days ago
Air Canada
Sun, May 4 - Sun, May 11
YUL
Montreal
STL
St. Louis
$433 Roundtrip, found 3 days ago
$433
Roundtrip
found 3 days ago
Select Air Canada flight, departing Sun, May 4 from Montreal to St. Louis, returning Sun, May 11, priced at $433 found 3 days ago
WestJet
Thu, Jun 5 - Sun, Jun 8
YUL
Montreal
STL
St. Louis
$534 Roundtrip, found 2 days ago
$534
Roundtrip
found 2 days ago
Select WestJet flight, departing Thu, Jun 5 from Montreal to St. Louis, returning Sun, Jun 8, priced at $534 found 2 days ago
Flights from Montreal (YUL) to St. Louis (STL)
Origin airport
Pierre Elliott Trudeau Intl.
Destination airport
Lambert-St. Louis Intl.
Airlines serving
Air Canada, American Airlines, Delta, United, WestJet
Roundtrip price
$405
Distance
967 mi

Montreal to St. Louis Flights

The cheapest times to fly from Montreal to St. Louis

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 Montreal to St. Louis are during the month of June. You can find some of the cheapest flights from Montreal to St. Louis with Expedia's search tool and vast selection of airlines.

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

Sunday is one of the best days to book for cheap flights from Montreal to St. Louis: 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 Montreal to St. Louis

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 Montreal to St. Louis in 2025. You can also book with separate airlines for your outbound and return journeys, from $210 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 Montreal to St. Louis 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 Montreal to St. Louis 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 Pierre Elliott Trudeau Intl. Airport (YUL) to Lambert-St. Louis Intl. Airport (STL) cost?
Snag cheap return fares starting at $422 from Pierre Elliott Trudeau Intl. Airport (YUL) to Lambert-St. Louis Intl. Airport (STL). 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 United flight leaving YUL on May 15 2025 and touching down at STL. The price was last updated on April 22 2025 and has not changed since.
What is the cheapest month to fly from YUL to STL?
The cheapest flights from YUL to STL 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 YUL to STL?
Currently, the cheapest airline offering one-way flights from YUL to STL is Air Canada. You can take off on this route from $238. This fare is based on the lowest price found on Expedia departing within the next three months. The flight takes off from YUL on May 12 2025. Prices were last updated on April 22 2025 and have not changed since.
How many flights per day from Pierre Elliott Trudeau Intl. Airport (YUL) to Lambert-St. Louis Intl. Airport (STL)?
You’ll need to catch a flight with a layover if you’re traveling from Pierre Elliott Trudeau Intl. Airport (YUL) to Lambert-St. Louis Intl. Airport (STL). Direct flights don’t operate daily on this route. However, simply filter your search to include one or two stops to discover the best option for your trip.
What day of the week has the most flights from YUL to STL?
You’ll typically find Tuesday the quietest day for flights, while Fridays tend to be the busiest.* However this can vary from season to season and during peak travel times or public holidays.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Pierre Elliott Trudeau Intl. Airport (YUL) to Lambert-St. Louis Intl. Airport (STL)?
To avoid possible delays on the Pierre Elliott Trudeau Intl. Airport (YUL) to Lambert-St. Louis Intl. Airport (STL) route, aim to fly before 3 PM. Departures after this time are 22% more likely to be canceled.**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 Pierre Elliott Trudeau Intl. Airport (YUL) to Lambert-St. Louis Intl. Airport (STL) last-minute?
Booking your ticket from YUL to STL right before your journey is typically more expensive. But if you’re flexible with your itinerary, you could grab a cheap last-minute fare.
Is it cheaper to book a YUL to STL flight and hotel package?
Compared with arranging hotels and flights separately, booking a YUL to STL flight and hotel package with Expedia could result in significant savings. Better yet, having everything in one easy place takes the hassle out of planning your trip. Just pick your flights and choose from our wide range of stays, then personalize your trip with extras like tours, activities and car rentals.
Can I cancel or change the date of my flight from Pierre Elliott Trudeau Intl. Airport (YUL) to Lambert-St. Louis Intl. Airport (STL)?
Generally, it’s possible to reschedule or cancel your YUL to STL flight. However, for bookings made more than 24 hours ago, additional fees may apply. Check your airline’s policies in your itinerary to see what changes are possible and if any costs are involved. You’ll also find further details on our Customer Service portal.

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*Available to One Key members.