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Cheap flights from Ontario to St. Louis from C$ 253

YYZ — STL
25 Oct — 1 Nov1
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

Tue 20/107:29 a.m. -
1 stop10h 24m
Tue 27/107:28 a.m. -
1 stop9h 16m
Deal found 21/9C$ 449
Wed 14/101:15 p.m. -
1 stop8h 42m
Sat 17/105:00 a.m. -
1 stop8h 33m
Deal found 21/9C$ 465
Wed 21/101:15 p.m. -
1 stop8h 42m
Wed 28/105:00 a.m. -
1 stop8h 33m
Deal found 22/9C$ 484
Thu 22/101:15 p.m. -
1 stop8h 42m
Mon 26/107:29 a.m. -
1 stop9h 15m
Deal found 22/9C$ 486
Thu 22/103:14 p.m. -
1 stop10h 05m
Fri 23/105:00 a.m. -
1 stop8h 33m
Deal found 21/9C$ 489
Fri 6/113:15 p.m. -
1 stop9h 44m
Fri 13/117:26 a.m. -
1 stop9h 15m
Deal found 22/9C$ 531
Wed 28/107:15 a.m. -
2 stops11h 25m
Wed 4/116:44 p.m. -
2 stops19h 36m
Deal found 24/9C$ 548
Tue 20/109:30 a.m. -
2 stops33h 10m
Sat 31/104:26 p.m. -
1 stop21h 14m
Deal found 22/9C$ 563
Thu 12/116:30 a.m. -
1 stop17h 46m
Mon 16/116:44 p.m. -
2 stops23h 36m
Deal found 24/9C$ 573
Sun 25/101:00 p.m. -
2 stops25h 31m
Sat 31/104:26 p.m. -
1 stop21h 14m
Deal found 22/9C$ 580
Thu 3/128:00 a.m. -
1 stop17h 12m
Mon 7/1212:02 p.m. -
2 stops35h 05m
Deal found 24/9C$ 698
Fri 23/104:00 p.m. -
3 stops27h 57m
Sat 31/107:59 p.m. -
3 stops28h 02m
Deal found 22/9C$ 792

Find flight deals from Ontario to St. Louis

Round-trip from

C$ 449

One-way from

C$ 253

Popular in

March

Cheapest in

January

Average price

C$ 890

Good round-trip deal

C$ 791 or less
American Airlines
  • American Airlines
  • 20/10-27/10
  • 2 total stops
  • 19h 40m total
  • Ontario to St. Louis
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10/11-31/12
  • 10/11-31/12
  • 2 total stops
  • 30h 20m total
  • Ontario to St. Louis
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Highest demand for flights based on searches. 15% potential increase in price (C$ 192 potential increase over avg. RT price).
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Cheapest flight prices on average. 7% potential price decrease (C$ 72 potential savings vs. average RT price).
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Average for round-trip flights in September 2026
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Price to beat on a round-trip flight from Ontario to Lambert-St Louis.
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Cheapflights Fare Finder

 
Use the filters below to find and compare flights from Ontario to St. Louis that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

TorontoSt. Louis

YYZ Toronto Pearson Intl - STL Lambert-St Louis

YYZSTL

Toronto Pearson Intl

Mon 2/11

1:00 p.m.-1:21 p.m.

2 stops25h 21m

Lambert-St Louis

Wed 31/12

12:00 a.m.-1:00 a.m.

Nonstop0h 00m

C$ 289

TorontoSt. Louis

YYZ Toronto Pearson Intl - STL Lambert-St Louis

YYZSTL

Toronto Pearson Intl

Thu 5/11

7:15 a.m.-5:40 p.m.

2 stops35h 25m

Lambert-St Louis

Wed 31/12

12:00 a.m.-1:00 a.m.

Nonstop0h 00m

C$ 357

TorontoSt. Louis

YYZ Toronto Pearson Intl - STL Lambert-St Louis

YYZSTL

Toronto Pearson Intl

Sat 7/11

12:00 p.m.-11:24 p.m.

2 stops12h 24m

Lambert-St Louis

Wed 31/12

12:00 a.m.-1:00 a.m.

Nonstop0h 00m

C$ 381

TorontoSt. Louis

YYZ Toronto Pearson Intl - STL Lambert-St Louis

YYZSTL

Toronto Pearson Intl

Thu 1/10

1:15 p.m.-8:44 p.m.

1 stop8h 29m

Lambert-St Louis

Wed 31/12

12:00 a.m.-1:00 a.m.

Nonstop0h 00m

C$ 405

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Fri 6/11

5:40 p.m.-7:14 p.m.

3 stops26h 34m

Lambert-St Louis

Wed 31/12

12:00 a.m.-1:00 a.m.

Nonstop0h 00m

C$ 408

TorontoSt. Louis

YYZ Toronto Pearson Intl - STL Lambert-St Louis

YYZSTL

Toronto Pearson Intl

Sun 29/11

9:10 a.m.-5:40 p.m.

3 stops33h 30m

Lambert-St Louis

Wed 31/12

12:00 a.m.-1:00 a.m.

Nonstop0h 00m

C$ 426

OttawaSt. Louis

YOW Ottawa - STL Lambert-St Louis

YOWSTL

Ottawa

Fri 6/11

6:00 a.m.-9:40 p.m.

2 stops16h 40m

Lambert-St Louis

Wed 31/12

12:00 a.m.-1:00 a.m.

Nonstop0h 00m

C$ 458

TorontoSt. Louis

YYZ Toronto Pearson Intl - STL Lambert-St Louis

YYZSTL

Toronto Pearson Intl

Fri 18/12

5:55 p.m.-11:38 p.m.

1 stop6h 43m

Lambert-St Louis

Wed 31/12

12:00 a.m.-1:00 a.m.

Nonstop0h 00m

C$ 474

TorontoSt. Louis

YYZ Toronto Pearson Intl - STL Lambert-St Louis

YYZSTL

Toronto Pearson Intl

Sat 26/12

9:44 a.m.-7:02 p.m.

2 stops10h 18m

Lambert-St Louis

Wed 31/12

12:00 a.m.-1:00 a.m.

Nonstop0h 00m

C$ 535

TorontoSt. Louis

YYZ Toronto Pearson Intl - STL Lambert-St Louis

YYZSTL

Toronto Pearson Intl

Thu 11/2

10:19 a.m.-9:13 p.m.

2 stops11h 54m

Lambert-St Louis

Tue 16/2

1:08 p.m.-12:19 a.m.

1 stop10h 11m

C$ 825

Flights are sorted by cheapest round-trip flights first.

Deals found on 22/9

Showing 1-10 of 29 resultsSorted by cheapest first
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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

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, January is the cheapest month in which you can book a flight from Region of Ontario to St. Louis (average of C$ 590). Flying from Region of Ontario to St. Louis in April is currently the most expensive (average of C$ 861). 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?

It’s optimal to fly from Region of Ontario to St. Louis in the afternoon. By choosing this option you can save up to 36% on the cost of your flight, compared to a flight in the evening.

Weekly flight availability from Region of Ontario to St. Louis

The most flights from CAON to STL are scheduled on a Monday (4 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (4 on average).

How much does it cost to fly round-trip from Region of Ontario to St. Louis?

Airfare is below average for this route at the moment.
Region of Ontario to St. Louis flights typically cost between C$ 626 and C$ 916 in October.
The cheapest round-trip price found within the last 5 days was C$ 449 on American Airlines (20 Oct-27 Oct).

How far ahead should I book a flight from Region of Ontario to St. Louis?

To ensure you get the cheapest price possible for a flight from Region of Ontario to St. Louis, you should look to book at least 46 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.

Related info for your journey

  • 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?

    United Airlines can get you from Region of Ontario to St. Louis in just under 11h 54m. Your travel time can differ by up to . The distance between Region of Ontario and St. Louis is about 1051 km.

  • 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 (68%), Jazz (68%) or United Airlines (68%) 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$ 890, our data indicates the cheapest price to be C$ 494. The most popular route (Toronto Pearson Intl - Lambert-St Louis), is priced around C$ 573.

  • 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, January is the cheapest month in which you can book a flight from Region of Ontario to St. Louis (average of C$ 590). Flying from Region of Ontario to St. Louis in April is currently the most expensive (average of C$ 861). 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
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Top 2 airlines flying from Ontario to St. Louis

AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapestC$ 339AverageC$ 621FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
United AirlinesCheapestC$ 345AverageC$ 649FlexibilityNo cancel feeOn-time69%
Search United Airlines flights

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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.

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