Find flights
Deals
When to book
FAQs

Cheap flights from Ontario to St. Louis from C$ 170

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 4/3. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — STL
28 Feb — 7 Mar1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Ontario to St. Louis

Enter your travel dates to find the best prices.

Cheapest flights from Ontario to St. Louis
Explore the most affordable flight options available from Ontario to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 29 January 2026.

Sat 21/23:40 p.m.
YYZ
-
STL
2 stops40h 11m
Multiple Airlines
Mon 2/33:49 p.m.
STL
-
YYZ
1 stop7h 40m
Multiple Airlines
Deal found 27/1C$ 372
Wed 25/27:10 a.m.
YYZ
-
STL
1 stop16h 17m
Multiple Airlines
Wed 4/38:17 p.m.
STL
-
YYZ
2 stops22h 38m
Multiple Airlines
Deal found 28/1C$ 387
Wed 25/26:00 a.m.
YYZ
-
STL
1 stop10h 35m
American Airlines
Wed 4/36:00 a.m.
STL
-
YYZ
1 stop10h 36m
American Airlines
Deal found 27/1C$ 398
Tue 3/37:15 a.m.
YYZ
-
STL
1 stop16h 12m
Multiple Airlines
Thu 5/33:49 p.m.
STL
-
YYZ
1 stop7h 25m
Multiple Airlines
Deal found 28/1C$ 405
Thu 5/28:20 p.m.
YYZ
-
STL
1 stop15h 03m
Multiple Airlines
Sun 8/25:42 p.m.
STL
-
YYZ
1 stop19h 38m
Multiple Airlines
Deal found 27/1C$ 409
Sat 28/27:10 a.m.
YYZ
-
STL
1 stop17h 49m
Multiple Airlines
Mon 9/37:47 a.m.
STL
-
YYZ
1 stop15h 27m
Multiple Airlines
Deal found 28/1C$ 432
Tue 24/25:11 p.m.
YOW
-
STL
1 stop4h 54m
United Airlines
Tue 3/36:25 a.m.
STL
-
YOW
2 stops7h 02m
United Airlines
Deal found 26/1C$ 433
Thu 9/45:20 p.m.
YOW
-
STL
1 stop6h 36m
United Airlines
Sat 11/47:45 a.m.
STL
-
YOW
1 stop5h 14m
United Airlines
Deal found 28/1C$ 437
Sat 28/31:10 p.m.
YYZ
-
STL
1 stop9h 01m
American Airlines
Tue 31/312:05 p.m.
STL
-
YYZ
1 stop8h 24m
American Airlines
Deal found 28/1C$ 452
Tue 24/21:10 p.m.
YYZ
-
STL
1 stop9h 02m
American Airlines
Sat 28/210:43 a.m.
STL
-
YYZ
1 stop9h 46m
American Airlines
Deal found 28/1C$ 460
Tue 17/24:44 p.m.
YYZ
-
STL
1 stop8h 04m
American Airlines
Sat 28/210:43 a.m.
STL
-
YYZ
1 stop9h 46m
American Airlines
Deal found 27/1C$ 467
Sat 9/57:00 a.m.
YOW
-
STL
1 stop6h 06m
Air Canada
Sat 16/57:30 a.m.
STL
-
YOW
1 stop6h 40m
Air Canada
Deal found 27/1C$ 483

Find flight deals from Ontario to St. Louis

Keep the following information in mind while searching for Ontario to St. Louis flight deals. Data was last updated 29 January 2026.

Round-trip from

C$ 372

One-way from

C$ 170

Popular in

September

Cheapest in

June

Average price

C$ 536

Good round-trip deal

C$ 573 or less
21/2-2/3
  • 21/2-2/3
  • 3 total stops
  • 47h 51m total
  • Ontario to St. Louis
Search Deals
4/3
  • 4/3
  • 1 total stop
  • 16h 12m total
  • Ontario to St. Louis
Search Deals
Highest demand for flights based on searches. 1% potential increase in price (C$ 12 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease (C$ 18 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in January 2026
Search Deals
Price to beat on a round-trip flight from Ontario to Lambert-St Louis.
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Ontario to St. Louis that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 629,999 searches. Data last updated 29 January 2026.
Use the filters below to find and compare flights from Ontario to St. Louis that are best for you.

Fly from

Ontario

Fly to

St. Louis

Route

Depart

Return

Price

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Sat 28/2

8:30 p.m.-6:51 a.m.

2 stops35h 21m

Lambert-St Louis

Mon 9/3

7:47 a.m.-12:14 a.m.

1 stop15h 27m

C$ 409

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Wed 25/2

4:44 p.m.-11:48 p.m.

1 stop8h 04m

Lambert-St Louis

Wed 4/3

6:00 a.m.-4:03 p.m.

1 stop9h 03m

C$ 417

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 24/2

5:11 p.m.-9:05 p.m.

1 stop4h 54m

Lambert-St Louis

Tue 3/3

6:25 a.m.-2:27 p.m.

2 stops7h 02m

C$ 433

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 26/2

5:11 p.m.-10:59 p.m.

1 stop6h 48m

Lambert-St Louis

Thu 5/3

7:41 a.m.-5:12 p.m.

1 stop8h 31m

C$ 433

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 9/4

6:00 a.m.-10:56 p.m.

3 stops17h 56m

Lambert-St Louis

Sat 11/4

7:45 a.m.-1:59 p.m.

1 stop5h 14m

C$ 437

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Wed 25/2

7:10 a.m.-10:27 p.m.

1 stop16h 17m

Lambert-St Louis

Wed 4/3

8:17 p.m.-7:55 p.m.

2 stops22h 38m

C$ 438

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Tue 24/2

1:10 p.m.-9:12 p.m.

1 stop9h 02m

Lambert-St Louis

Sat 28/2

10:43 a.m.-9:29 p.m.

1 stop9h 46m

C$ 460

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Wed 29/4

7:20 a.m.-9:47 p.m.

2 stops15h 27m

Lambert-St Louis

Wed 6/5

10:00 a.m.-6:33 p.m.

1 stop7h 33m

C$ 467

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Sun 1/3

10:05 a.m.-6:51 a.m.

2 stops21h 46m

Lambert-St Louis

Wed 4/3

3:49 p.m.-11:26 a.m.

1 stop18h 37m

C$ 493

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Sun 1/3

6:00 a.m.-6:08 p.m.

1 stop13h 08m

Lambert-St Louis

Wed 4/3

9:37 a.m.-9:29 p.m.

1 stop10h 52m

C$ 502

Flights are sorted by cheapest round-trip flights first.

Deals found on 28/1

Showing 1-10 of 46 results
1
2
3
...
5

Best time to book a flight from Ontario to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Ontario with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Ontario to St. Louis

What is the cheapest month to book a flight from Region of Ontario to St. Louis?

Currently, December is the cheapest month in which you can book a flight from Region of Ontario to St. Louis (average of C$ 335). Flying from Region of Ontario to St. Louis in April is currently the most expensive (average of C$ 505). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from ON to STL?

Find hourly flight availability from Ontario to St. Louis. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 29 January 2026.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Region of Ontario to St. Louis as you normally would.

Weekly flight availability from Region of Ontario to St. Louis

Explore weekly flight availability from Ontario to St. Louis. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated 29 January 2026.

The most flights from CAON to STL are scheduled on a Monday (2 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (2 on average).

Related info for your journey

Find useful and relevant information for your journey from Ontario to St. Louis. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly into for flights to St. Louis from Ontario?

    Most people fly into Lambert-St Louis (STL) if they book a flight to St. Louis from Ontario. Lambert-St Louis is conveniently located just 20.4 km from St. Louis’s city centre.

  • How long is the flight from Region of Ontario to St. Louis?

    American Airlines, United Airlines, and Delta can get you from Region of Ontario to St. Louis in just under 4h 46m. Your travel time can differ by up to 3h 18m. The distance between Region of Ontario and St. Louis is about 1556 km. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.

  • What are the most popular routes from Region of Ontario to St. Louis?

    While some choose either Montreal Pierre Elliott Trudeau Intl - Lambert-St Louis or Ottawa - Lambert-St Louis, Toronto Pearson Intl - Lambert-St Louis is the most popular route from Region of Ontario to St. Louis.

  • What are the most reliable airlines from Region of Ontario to St. Louis?

    Consider Air Canada (83%), Jazz (83%) or United Airlines (83%) when booking your flight. These represent the most reliable airlines when flying from Region of Ontario to St. Louis.

  • What are the cheapest flights from Region of Ontario to St. Louis?

    Looking for the cheapest flight from Region of Ontario to St. Louis? While on average our users pay C$ 573, our data indicates the cheapest price to be C$ 487. The most popular route (Toronto Pearson Intl - Lambert-St Louis), is priced around C$ 405.

  • Can I find deals for flights from Ontario to St. Louis that include hotel bookings?

    Yes. In addition to deals on Ontario to St. Louis flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Ontario to St. Louis?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Ontario to St. Louis.

  • Can I find deals for business class flights from Ontario to St. Louis?

    Yes. Cheapflights offers flight deals from Ontario to St. Louis by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Region of Ontario to St. Louis?

    Currently, December is the cheapest month in which you can book a flight from Region of Ontario to St. Louis (average of C$ 335). Flying from Region of Ontario to St. Louis in April is currently the most expensive (average of C$ 505). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Travelling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
Chesterfield

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Ontario to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.
Pearson Intl to St. Louis flights
Vancouver Intl to St. Louis flights
Pierre Elliott Trudeau Intl to Kansas City flights
Vancouver Intl to Kansas City flights
Pierre Elliott Trudeau Intl to St. Louis flights
Pearson Intl to Kansas City flights
Edmonton to Kansas City flights
Abbotsford to Kansas City flights
Vancouver Intl to Springfield flights
Calgary to Kansas City flights
Québec City to St. Louis flights
Saskatoon to Kansas City flights
Calgary to St. Louis flights
Edmonton to St. Louis flights
Ottawa to St. Louis flights
Ottawa to Kansas City flights
Victoria to St. Louis flights
Halifax to St. Louis flights
Pearson Intl to Columbia flights
Winnipeg to Kansas City flights
Pearson Intl to Springfield flights
Victoria to Kansas City flights
Saskatoon to St. Louis flights
Charlottetown to St. Louis flights
Comox to Kansas City flights
Halifax to Kansas City flights
Calgary to Columbia flights
Edmonton to Columbia flights
Pearson Intl to Quincy flights
Regina to Branson flights
Pierre Elliott Trudeau Intl to Cape Girardeau flights

Top 5 airlines flying from Ontario to St. Louis

Discover the top 5 airlines that operate flights from Ontario to St. Louis. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 629,999 searches. Data last updated 29 January 2026.
AirlineCheapestAverageFlexibilityOn-time
United AirlinesCheapestC$ 327AverageC$ 659FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
American AirlinesCheapestC$ 366AverageC$ 674FlexibilityNo cancel feeOn-time71%
Search American Airlines flights
Air CanadaCheapestC$ 452AverageC$ 723FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
DeltaCheapestC$ 466AverageC$ 602FlexibilityNo cancel feeOn-timeN/A
Search Delta flights
WestJetCheapestC$ 548AverageC$ 755FlexibilityNo cancel feeOn-time60%
Search WestJet flights

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travelers can enjoy low prices and a wide availability of flights to their desired destinations.

How does Cheapflights help users find flights from Ontario to St. Louis?

When you search for this flight from Ontario to St. Louis, Cheapflights searches on 900+ travel sites to save you time finding great flight deals online. Additionally, we offer filter features so you can choose a preferred cabin class or airline, see different price ranges, and much more so you can book the flight for you.

Why should you use Cheapflights to find cheap flight tickets from Ontario to St. Louis?

Cheapflights helps you find that perfect flight to St. Louis from Ontario by searching from hundreds of airlines and agencies you know and love. We are also free to use, in case you were wondering!

Can Cheapflights find flights from Ontario to St. Louis with no change fees?

Certainly. Search results for flights to St. Louis from Ontario shown to you on Cheapflights can be narrowed down with different useful search filters, which includes flexible booking options.

Can Cheapflights notify me if prices for flights from Ontario to St. Louis become cheaper?

Yes! Start tracking prices for Ontario to St. Louis flights today and get alerted whenever prices for these flights change. To access this feature, click the bell icon next to the flight deals above, which will prompt you for a valid email address to receive your alerts.

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.