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Cheap flights from Ontario to St. Louis from C$ 213

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 7/5. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — STL
27 Apr — 4 May1
1 adult

Cheap 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 22 April 2025.

Round-trip from

C$ 506

One-way from

C$ 213

Popular in

January

Cheapest in

November

Average price

C$ 713

Good round-trip deal

C$ 540 or less

Good one-way deal

C$ 621 or less
American Airlines
  • American Airlines
  • 13/5-16/5
  • 2 total stops
  • 12h 33m total
  • Ontario to St. Louis
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7/5
  • 7/5
  • 1 total stop
  • 9h 06m total
  • Ontario to St. Louis
Search Deals
Highest demand for flights based on searches. 3% potential increase in price (C$ 36 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 0% potential price decrease (C$ 10 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in April 2025
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Price to beat on a round-trip flight from Ontario to Lambert-St Louis.
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Price to beat on a one-way flight from Ontario to Lambert-St Louis.
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Find flight deals from Ontario to St. Louis

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 22 April 2025.

Tue 13/56:30 a.m.YYZ - STL
1 stop7h 37mAmerican Airlines
Fri 16/56:00 a.m.STL - YYZ
1 stop5h 30mAmerican Airlines
Deal found 22/4C$ 506
Mon 12/54:00 p.m.YYZ - STL
1 stop9h 06mMultiple Airlines
Fri 16/59:50 a.m.STL - YYZ
2 stops10h 18mMultiple Airlines
Deal found 22/4C$ 509
Thu 5/61:00 p.m.YYZ - STL
1 stop7h 58mAir Canada
Tue 10/65:27 p.m.STL - YYZ
1 stop5h 31mAir Canada
Deal found 21/4C$ 510
Wed 30/46:15 a.m.YUL - STL
1 stop18h 49mMultiple Airlines
Mon 5/59:55 p.m.STL - YUL
2 stops21h 02mMultiple Airlines
Deal found 22/4C$ 518
Mon 2/66:10 p.m.YUL - STL
Nonstop2h 48mAir Canada
Mon 9/67:30 a.m.STL - YUL
1 stop4h 51mAir Canada
Deal found 21/4C$ 539
Fri 6/611:30 a.m.YYZ - STL
Nonstop2h 06mUnited Airlines
Fri 13/65:00 a.m.STL - YYZ
1 stop15h 16mUnited Airlines
Deal found 22/4C$ 561
Wed 21/58:00 a.m.YYZ - STL
2 stops10h 00mWestJet
Tue 27/56:00 a.m.STL - YYZ
2 stops11h 04mWestJet
Deal found 21/4C$ 641
Mon 2/68:30 a.m.YUL - STL
2 stops8h 00mUnited Airlines
Mon 9/67:00 a.m.STL - YUL
1 stop5h 09mUnited Airlines
Deal found 21/4C$ 661
Sat 7/612:59 p.m.YUL - STL
1 stop5h 08mAmerican Airlines
Sat 7/68:05 p.m.STL - YUL
1 stop14h 25mAmerican Airlines
Deal found 21/4C$ 665
Sat 10/56:05 a.m.YUL - STL
1 stop27h 02mKLM
Thu 15/57:05 a.m.STL - YUL
1 stop9h 35mKLM
Deal found 22/4C$ 740
Sat 26/46:00 a.m.YYZ - STL
2 stops13h 50mDelta
Sat 3/54:15 p.m.STL - YYZ
2 stops16h 15mDelta
Deal found 21/4C$ 760
Thu 15/56:45 p.m.YUL - STL
1 stop15h 15mWestJet
Sun 18/56:00 a.m.STL - YUL
2 stops17h 37mWestJet
Deal found 21/4C$ 774

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 22 April 2025.
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

Tue 13/5

3:10 p.m.-9:52 p.m.

1 stop7h 42m

Lambert-St Louis

Fri 16/5

6:00 a.m.-12:30 p.m.

1 stop5h 30m

C$ 506

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Thu 5/6

1:00 p.m.-7:58 p.m.

1 stop7h 58m

Lambert-St Louis

Tue 10/6

5:27 p.m.-11:58 p.m.

1 stop5h 31m

C$ 510

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Mon 5/5

4:00 p.m.-12:06 a.m.

1 stop9h 06m

Lambert-St Louis

Tue 6/5

5:45 p.m.-11:47 p.m.

1 stop29h 02m

C$ 521

MontrealSt. Louis

YUL - STL

YULSTL

Montreal Pierre Elliott Trudeau Intl

Mon 2/6

6:10 p.m.-7:58 p.m.

Nonstop2h 48m

Lambert-St Louis

Mon 9/6

7:30 a.m.-1:21 p.m.

1 stop4h 51m

C$ 539

MontrealSt. Louis

YUL - STL

YULSTL

Montreal Pierre Elliott Trudeau Intl

Sat 10/5

6:45 a.m.-9:15 a.m.

2 stops27h 30m

Lambert-St Louis

Thu 15/5

10:10 a.m.-8:42 a.m.

2 stops21h 32m

C$ 549

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Fri 6/6

11:30 a.m.-12:36 p.m.

Nonstop2h 06m

Lambert-St Louis

Fri 13/6

5:00 a.m.-9:16 p.m.

1 stop15h 16m

C$ 561

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Wed 21/5

8:00 a.m.-5:00 p.m.

2 stops10h 00m

Lambert-St Louis

Tue 27/5

6:00 a.m.-6:04 p.m.

2 stops11h 04m

C$ 641

MontrealSt. Louis

YUL - STL

YULSTL

Montreal Pierre Elliott Trudeau Intl

Mon 2/6

8:30 a.m.-3:30 p.m.

2 stops8h 00m

Lambert-St Louis

Mon 9/6

7:00 a.m.-1:09 p.m.

1 stop5h 09m

C$ 661

MontrealSt. Louis

YUL - STL

YULSTL

Montreal Pierre Elliott Trudeau Intl

Sat 7/6

12:59 p.m.-5:07 p.m.

1 stop5h 08m

Lambert-St Louis

Sat 7/6

8:05 p.m.-11:30 a.m.

1 stop14h 25m

C$ 665

MontrealSt. Louis

YUL - STL

YULSTL

Montreal Pierre Elliott Trudeau Intl

Sat 10/5

6:05 a.m.-8:07 a.m.

1 stop27h 02m

Lambert-St Louis

Thu 15/5

7:05 a.m.-5:40 p.m.

1 stop9h 35m

C$ 740

Flights are sorted by cheapest round-trip flights first.

Deals found on 21/4

Showing 1-10 of 27 results
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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
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, January is the cheapest month in which you can book a flight from Region of Ontario to St. Louis (average of C$ 365). Flying from Region of Ontario to St. Louis in September is currently the most expensive (average of C$ 491). 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 22 April 2025.

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 22 April 2025.

The most flights from CAON to STL are scheduled on a Monday (2 on average). You will have fewer flight options on Thursday, which is when the least amount of flights are scheduled (1 on average).

Rainfall in St. Louis by month

Plan your trip to St. Louis by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in St. Louis ranges from 56.0 - 119.0 mm per month. May is typically the wettest month, when rainfall can reach 119.0 mm. February is typically the driest time to visit St. Louis when rainfall is around 56.0 mm.

Temperature in St. Louis by month

Plan your trip to St. Louis by taking into account the average temperature totals by month.

If weather is an important factor for your trip to St. Louis, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 27.0 C. Travellers hoping to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 0.0 C).

Reviews of airlines servicing St. Louis

Get insights into the airlines that provide service to St. Louis. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to St. Louis. Reviews last updated 22 April 2025.
See what other customers who have flown with Alaska Airlines, Delta and KLM from Ontario to St. Louis have to say. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
9,911 reviews
Check prices

Comfort

7.9

Overall

8.0

Food

7.1

Crew

8.5

Boarding

8.2

Entertainment

7.1

Reviews

1 / 20
4.0
Okay

Anonymous,Apr 2025

LAS - STS

flight was delayed both ways even tho the weather was clear >
Alaska Airlines
8.0
Very good
9,911 reviews
Alaska Airlines
8.0
Very good
9,911 reviews
Check prices

Comfort

7.9

Overall

8.0

Food

7.1

Crew

8.5

Boarding

8.2

Entertainment

7.1

Reviews

1 / 20
4.0
Okay

Anonymous,Apr 2025

LAS - STS

flight was delayed both ways even tho the weather was clear >
Delta
8.0
Very good
7,920 reviews
Alaska Airlines
8.0
Very good
9,911 reviews
Check prices

Comfort

7.9

Overall

8.0

Food

7.1

Crew

8.5

Boarding

8.2

Entertainment

7.1

Reviews

1 / 20
4.0
Okay

Anonymous,Apr 2025

LAS - STS

flight was delayed both ways even tho the weather was clear >
KLM
7.8
Good
1,331 reviews
Alaska Airlines
8.0
Very good
9,911 reviews
Check prices

Comfort

7.9

Overall

8.0

Food

7.1

Crew

8.5

Boarding

8.2

Entertainment

7.1

Reviews

1 / 20
4.0
Okay

Anonymous,Apr 2025

LAS - STS

flight was delayed both ways even tho the weather was clear >
United Airlines
7.4
Good
8,683 reviews
Alaska Airlines
8.0
Very good
9,911 reviews
Check prices

Comfort

7.9

Overall

8.0

Food

7.1

Crew

8.5

Boarding

8.2

Entertainment

7.1

Reviews

1 / 20
4.0
Okay

Anonymous,Apr 2025

LAS - STS

flight was delayed both ways even tho the weather was clear >
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
9,911 reviews
Check prices

Comfort

7.9

Overall

8.0

Food

7.1

Crew

8.5

Boarding

8.2

Entertainment

7.1

Reviews

1 / 20
4.0
Okay

Anonymous,Apr 2025

LAS - STS

flight was delayed both ways even tho the weather was clear >

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.

  • What are the cheapest airlines to fly from Region of Ontario to St. Louis one-way?

    For one-way options, check prices for Delta. According to our data, you can fly for as low as C$ 290. Users have also found prices from C$ 296 and C$ 303 on American Airlines and Air Canada, respectively.

  • 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 (79%), Jazz (79%) or United Airlines (79%) 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$ 584, our data indicates the cheapest price to be C$ 331. The most popular route (Toronto Pearson Intl - Lambert-St Louis), is priced around C$ 460.

  • 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$ 365). Flying from Region of Ontario to St. Louis in September is currently the most expensive (average of C$ 491). 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 Ontario?

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

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Alternative routes for Ontario to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.
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Pearson Intl to Columbia flights
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Pierre Elliott Trudeau Intl to Cape Girardeau flights

Top 3 airlines flying from Ontario to St. Louis

Discover the top 3 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 22 April 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapestC$ 512AverageC$ 783FlexibilityNo cancel feeOn-time67%
Search Air Canada flights
United AirlinesCheapestC$ 565AverageC$ 681FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
WestJetCheapestC$ 610AverageC$ 754FlexibilityNo 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.

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