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$70+ Cheap flights from St. Louis (STL) to Ontario

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 3/27. Fares are subject to change and may not be available on all flights or dates of travel.
STL — YYZ
Feb 25 — Mar 41
Tue 2/25
Tue 3/4
1 adult, Economy
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Cheap flight deals from St. Louis to Ontario

Keep the following information in mind while searching for St. Louis to Ontario flight deals. Data was last updated February 20, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$215
(Mytrip)

One-way from

$70
(Mytrip)

Popular in

February

Cheapest in

May

Average price

$653

Good round-trip deal

$820 or less

Good one-way deal

$402 or less
Provider with most accurate pricing for Lambert-St Louis-Toronto (YTO) flight deals.
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Provider most trusted by Cheapflights users for Lambert-St Louis-Toronto (YTO) flights.
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From Lambert-St Louis to Ontario
Search Deals
One-way flight from Lambert-St Louis to Ontario
Search Deals
Highest demand for flights based on searches. 16% potential increase in price ($80 potential increase over avg. RT price).
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Cheapest flight prices on average. 5% potential price decrease ($22 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in February 2025
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Price to beat on a round-trip flight from Lambert-St Louis to Ontario.
Search Deals
Price to beat on a one-way flight from Lambert-St Louis to Ontario.
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Find flight deals from St. Louis to Ontario

Cheapest flights from St. Louis to Ontario
Explore the most affordable flight options available from St. Louis to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on February 20, 2025.

This Mytrip deal was found by Cheapflights users on 2/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/16:47 pmSTL - YYZ
1 stop28h 08mMultiple Airlines
Thu 4/37:05 amYYZ - STL
1 stop11h 47mMultiple Airlines
Deal found 2/19$215
This Mytrip deal was found by Cheapflights users on 2/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/106:11 pmSTL - YUL
1 stop19h 44mMultiple Airlines
Sun 4/136:45 amYUL - STL
2 stops11h 31mMultiple Airlines
Deal found 2/20$283
This Kiwi.com deal was found by Cheapflights users on 2/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 3/211:08 pmSTL - YOW
1 stop16h 37mMultiple Airlines
Mon 3/314:20 pmYOW - STL
1 stop8h 29mMultiple Airlines
Deal found 2/20$336
This Delta deal was found by Cheapflights users on 2/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 3/319:30 amSTL - YYZ
1 stop10h 01mDelta
Mon 4/76:14 amYYZ - STL
1 stop9h 32mDelta
Deal found 2/20$434
This Delta deal was found by Cheapflights users on 2/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 3/316:10 amSTL - YUL
1 stop9h 18mDelta
Mon 4/76:00 amYUL - STL
1 stop9h 46mDelta
Deal found 2/20$447
This Air Canada deal was found by Cheapflights users on 2/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 3/205:33 pmSTL - YYZ
1 stop5h 26mAir Canada
Thu 3/279:00 amYYZ - STL
1 stop4h 12mAir Canada
Deal found 2/20$467
This United Airlines deal was found by Cheapflights users on 2/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/239:39 amSTL - YYZ
1 stop8h 03mUnited Airlines
Sat 4/268:00 amYYZ - STL
2 stops13h 04mUnited Airlines
Deal found 2/19$485
This American Airlines deal was found by Cheapflights users on 2/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/2312:03 pmSTL - YYZ
1 stop9h 57mAmerican Airlines
Sat 4/263:14 pmYYZ - STL
1 stop7h 58mAmerican Airlines
Deal found 2/20$489
This American Airlines deal was found by Cheapflights users on 2/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/45:00 pmSTL - YUL
1 stop15h 50mAmerican Airlines
Sat 4/512:30 pmYUL - STL
1 stop10h 42mAmerican Airlines
Deal found 2/20$490
This Kiwi.com deal was found by Cheapflights users on 2/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/235:40 pmSTL - YYZ
1 stop5h 17mWestJet
Sun 5/256:00 amYYZ - STL
1 stop4h 31mWestJet
Deal found 2/18$555
This United deal was found by Cheapflights users on 2/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/25:29 pmSTL - YUL
2 stops22h 29mUnited Airlines
Sun 5/46:40 pmYUL - STL
1 stop22h 07mUnited Airlines
Deal found 2/20$555
This Air Canada deal was found by Cheapflights users on 2/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/21:30 pmSTL - YUL
Nonstop2h 30mAir Canada
Sun 5/46:10 pmYUL - STL
Nonstop2h 51mAir Canada
Deal found 2/20$571

Find flights from St. Louis to Ontario within your budget

Customize your flight search to find flights from St. Louis to Ontario 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 2,558,603 searches. Data last updated February 20, 2025.

Fly from

St. Louis

Fly to

Ontario

Route

Depart

Return

Price

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Tue 4/1

6:47 pm-11:55 pm

1 stop28h 08m

Toronto Pearson Intl

Thu 4/3

7:05 am-5:52 pm

1 stop11h 47m

$215

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Thu 4/10

6:11 pm-2:55 pm

1 stop19h 44m

Montreal Pierre Elliott Trudeau Intl

Sun 4/13

6:45 am-5:16 pm

2 stops11h 31m

$283

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 3/2

11:08 pm-4:45 pm

1 stop16h 37m

Ottawa

Mon 3/31

4:20 pm-11:49 pm

1 stop8h 29m

$336

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Mon 3/31

9:30 am-8:31 pm

1 stop10h 01m

Toronto Pearson Intl

Mon 4/7

6:14 am-2:46 pm

1 stop9h 32m

$434

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Mon 3/31

6:10 am-4:28 pm

1 stop9h 18m

Montreal Pierre Elliott Trudeau Intl

Mon 4/7

6:00 am-2:46 pm

1 stop9h 46m

$447

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Thu 3/20

5:33 pm-11:59 pm

1 stop5h 26m

Toronto Pearson Intl

Thu 3/27

9:00 am-12:12 pm

1 stop4h 12m

$467

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Wed 4/23

9:39 am-6:42 pm

1 stop8h 03m

Toronto Pearson Intl

Sat 4/26

8:00 am-8:04 pm

2 stops13h 04m

$485

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Wed 4/23

12:03 pm-11:00 pm

1 stop9h 57m

Toronto Pearson Intl

Sat 4/26

3:14 pm-10:12 pm

1 stop7h 58m

$489

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Fri 4/4

5:00 pm-9:50 am

1 stop15h 50m

Montreal Pierre Elliott Trudeau Intl

Sat 4/5

12:30 pm-10:12 pm

1 stop10h 42m

$490

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Fri 5/23

5:40 pm-11:57 pm

1 stop5h 17m

Toronto Pearson Intl

Sun 5/25

6:00 am-9:31 am

1 stop4h 31m

$555

Flights are sorted by cheapest round-trip flights first.

Deals found on 2/19

Showing 1-10 of 23 results
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Best time to book a flight from St. Louis to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from St. Louis 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.

Travel insights for flights from St. Louis to Ontario

Get recent, data-driven insights about flights from St. Louis to Ontario including ideal travel times, pricing trends, and more.

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

Currently, January is the cheapest month in which you can book a flight from St. Louis to Region of Ontario (average of $243). Flying from St. Louis to Region of Ontario in July is currently the most expensive (average of $359). 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 STL to ON?

Find hourly flight availability from St. Louis to Ontario. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated February 20, 2025.

When flying from St. Louis to Region of Ontario, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

Weekly flight availability from St. Louis to Region of Ontario

Explore weekly flight availability from St. Louis to Ontario. 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 February 20, 2025.

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

Rainfall in Ontario by month

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

In terms of precipitation, rainfall in Region of Ontario ranges from 2.0 - 3.3 inches per month. June is typically the wettest month, when rainfall can reach 3.3 in. February is typically the driest time to visit Region of Ontario when rainfall is around 2.0 in.

Temperature in Ontario by month

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

If weather is an important factor for your trip to Region of Ontario, 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 69.8 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 21.2 F).

Reviews of airlines servicing Ontario

Get insights into the airlines that provide service to Ontario. 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 Ontario. Reviews last updated February 20, 2025.
Peruse reviews from past customers who have flown with Alaska Airlines, Delta and United Airlines from St. Louis to Ontario to help guide your decision. In addition to providing an overall rating, users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
9,692 reviews

Food

7.1

Overall

8.0

Comfort

7.9

Crew

8.5

Entertainment

7.1

Boarding

8.2

Reviews

1 / 20

10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

Alaska Airlines
8.0
Very good
9,692 reviews
Alaska Airlines
8.0
Very good
9,692 reviews

Food

7.1

Overall

8.0

Comfort

7.9

Crew

8.5

Entertainment

7.1

Boarding

8.2

Reviews

1 / 20

10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

Delta
8.0
Very good
8,220 reviews
Alaska Airlines
8.0
Very good
9,692 reviews

Food

7.1

Overall

8.0

Comfort

7.9

Crew

8.5

Entertainment

7.1

Boarding

8.2

Reviews

1 / 20

10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

United Airlines
7.4
Good
8,766 reviews
Alaska Airlines
8.0
Very good
9,692 reviews

Food

7.1

Overall

8.0

Comfort

7.9

Crew

8.5

Entertainment

7.1

Boarding

8.2

Reviews

1 / 20

10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
9,692 reviews

Food

7.1

Overall

8.0

Comfort

7.9

Crew

8.5

Entertainment

7.1

Boarding

8.2

Reviews

1 / 20

10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

WestJet
7.2
Good
2,801 reviews
Alaska Airlines
8.0
Very good
9,692 reviews

Food

7.1

Overall

8.0

Comfort

7.9

Crew

8.5

Entertainment

7.1

Boarding

8.2

Reviews

1 / 20

10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

Related info for your journey

Find useful and relevant information for your journey from St. Louis to Ontario. 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 from for flights from St. Louis to Ontario?

    Lambert-St Louis (STL) is the airport you will fly out of if you book a flight from St. Louis to Ontario. It is only a 12.7 mi journey to Lambert-St Louis (STL) from St. Louis’s city center.

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

    One-way options have recently been found by users for as low as $192 on Delta. Other airlines that offer cheap prices include Air Canada from $198 and United Airlines from $205 one-way.

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

    When deciding which route to take from St. Louis to Region of Ontario consider Lambert-St Louis - Toronto Pearson Intl, Lambert-St Louis - Montreal Pierre Elliott Trudeau Intl or Lambert-St Louis - Ottawa as they are the most popular.

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

    No one likes to see their flight delayed. When booking a flight from St. Louis to Region of Ontario consider choosing Air Canada (73%), Jazz (73%) or United Airlines (73%) as they are the most reliable in getting you off to your destination on time.

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

    Looking for the cheapest flight from St. Louis to Region of Ontario? While on average our users pay $1,127, our data indicates the cheapest price to be $323. The most popular route (Lambert-St Louis - Toronto Pearson Intl), is priced around $215.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from St. Louis to Ontario 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 St. Louis to Region of Ontario?

    Currently, January is the cheapest month in which you can book a flight from St. Louis to Region of Ontario (average of $243). Flying from St. Louis to Region of Ontario in July is currently the most expensive (average of $359). 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

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Alternative routes for St. Louis to Ontario

See prices for flight routes from nearby airports that may be better suited for you.
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Top 3 airlines flying from St. Louis to Ontario

Discover the top 3 airlines that operate flights from St. Louis to Ontario. 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 2,558,603 searches. Data last updated February 20, 2025.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$215Average$629FlexibilityNo cancel feeOn-time67%
United AirlinesCheapest$247Average$690FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$304Average$578FlexibilityNo cancel feeOn-time71%
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