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

For one-way options, check prices for Air Canada. According to our data, you can fly for as low as C$ 327. Users have also found prices from C$ 343 and C$ 350 on United Airlines and Delta, 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 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$ 441, our data indicates the cheapest price to be C$ 294. The most popular route (Toronto Pearson Intl - Lambert-St Louis), is priced around C$ 504.

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 most popular airlines that fly from Region of Ontario to St. Louis?

Before booking your flight from Region of Ontario to St. Louis check out the most popular airlines for this route: Air Canada, United Airlines or WestJet.

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

Find a great deal and save up to 224% by booking at least 47 days prior to your desired departure date, rather than waiting until the week of travel. According to our data, there are a number of flights available from Region of Ontario to St. Louis within the next two weeks, with the cheapest ticket starting at C$ 771.

What is the cheapest month to fly from Region of Ontario to St. Louis?

Flights from Region of Ontario to St. Louis lean towards being more expensive in January. Prices are generally better when you fly from Region of Ontario to St. Louis in November, with the cheapest ticket starting at C$ 401.

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.

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.

C$ 241+ Flights from Ontario to St. Louis

Cheap flight deals from Ontario to St. Louis

Round-trip from	C$ 498
One-way from	C$ 260
Popular in	January
Cheapest in	November
Average price	C$ 714
Good round-trip deal	C$ 544 or less
Good one-way deal	C$ 294 or less

10/5-12/5
2 total stops
53h 02m total
Ontario to St. Louis

Search Deals

25/5
1 total stop
8h 52m total
Ontario to St. Louis

Search Deals

Highest demand for flights based on searches. 4% potential increase in price (C$ 40 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 1% potential price decrease (C$ 10 potential savings vs. average RT price).

Search Deals

Average for round-trip flights in April 2025

Search Deals

Price to beat on a round-trip flight from Ontario to Lambert-St Louis.

Search Deals

Price to beat on a one-way flight from Ontario to Lambert-St Louis.

Search Deals

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 30 April 2025.

Sat 10/56:30 a.m.YYZ - STL

1 stop27h 45mMultiple Airlines

Mon 12/59:55 p.m.STL - YYZ

1 stop25h 17mMultiple Airlines

Deal found 27/4C$ 498

Mon 23/611:30 a.m.YYZ - STL

Nonstop2h 06mUnited Airlines

Wed 25/67:30 a.m.STL - YYZ

Nonstop1h 55mUnited Airlines

Deal found 28/4C$ 561

Fri 30/53:50 p.m.YOW - STL

1 stop18h 25mMultiple Airlines

Sun 1/65:45 p.m.STL - YOW

1 stop22h 21mMultiple Airlines

Deal found 29/4C$ 563

Fri 30/59:49 a.m.YYZ - STL

1 stop4h 30mDelta

Sun 1/66:00 a.m.STL - YYZ

1 stop6h 40mDelta

Deal found 28/4C$ 568

Thu 22/511:30 a.m.YYZ - STL

Nonstop2h 06mAir Canada

Sun 25/52:30 p.m.STL - YYZ

Nonstop2h 00mAir Canada

Deal found 29/4C$ 577

Fri 5/96:24 p.m.YYZ - STL

1 stop6h 25mAmerican Airlines

Sun 7/95:29 a.m.STL - YYZ

1 stop8h 26mAmerican Airlines

Deal found 28/4C$ 580

Thu 22/56:30 a.m.YYZ - STL

1 stop4h 19mBritish Airways

Sun 25/56:12 a.m.STL - YYZ

2 stops7h 21mBritish Airways

Deal found 29/4C$ 642

Wed 23/711:00 a.m.YUL - STL

1 stop10h 57mDelta

Sat 26/79:16 a.m.STL - YUL

1 stop8h 37mDelta

Deal found 29/4C$ 648

Mon 5/56:45 a.m.YUL - STL

2 stops18h 21mMultiple Airlines

Mon 12/55:45 p.m.STL - YUL

1 stop19h 35mMultiple Airlines

Deal found 28/4C$ 657

Mon 23/68:00 p.m.YYZ - STL

2 stops14h 43mWestJet

Thu 26/610:48 a.m.STL - YYZ

1 stop5h 18mWestJet

Deal found 28/4C$ 684

Tue 17/66:00 a.m.YUL - STL

1 stop7h 36mAir Canada

Sun 22/61:30 p.m.STL - YUL

Nonstop2h 30mAir Canada

Deal found 29/4C$ 700

Tue 17/66:15 a.m.YUL - STL

1 stop7h 05mUnited Airlines

Sun 22/68:10 a.m.STL - YUL

1 stop12h 19mUnited Airlines

Deal found 29/4C$ 702

Best flights from Ontario to St. Louis
Discover carefully curated flight deals from Ontario to St. Louis that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated 30 April 2025.

Sat 10/56:30 a.m.YYZ - STL

1 stop27h 45mMultiple Airlines

Mon 12/59:55 p.m.STL - YYZ

1 stop25h 17mMultiple Airlines

Deal found 27/4C$ 498

Mon 23/611:30 a.m.YYZ - STL

Nonstop2h 06mUnited Airlines

Wed 25/67:30 a.m.STL - YYZ

Nonstop1h 55mUnited Airlines

Deal found 28/4C$ 561

Fri 30/59:49 a.m.YYZ - STL

1 stop4h 30mDelta

Sun 1/66:00 a.m.STL - YYZ

1 stop6h 40mDelta

Deal found 28/4C$ 568

Thu 22/511:30 a.m.YYZ - STL

Nonstop2h 06mAir Canada

Sun 25/52:30 p.m.STL - YYZ

Nonstop2h 00mAir Canada

Deal found 29/4C$ 577

Fri 5/96:24 p.m.YYZ - STL

1 stop6h 25mAmerican Airlines

Sun 7/95:29 a.m.STL - YYZ

1 stop8h 26mAmerican Airlines

Deal found 28/4C$ 580

Thu 22/56:30 a.m.YYZ - STL

1 stop4h 19mBritish Airways

Sun 25/56:12 a.m.STL - YYZ

2 stops7h 21mBritish Airways

Deal found 29/4C$ 642

Mon 23/68:00 p.m.YYZ - STL

2 stops14h 43mWestJet

Thu 26/610:48 a.m.STL - YYZ

1 stop5h 18mWestJet

Deal found 28/4C$ 684

Thu 15/55:29 p.m.YYZ - STL

1 stop5h 59mWestJet Encore

Mon 19/56:00 p.m.STL - YYZ

1 stop19h 33mWestJet Encore

Deal found 28/4C$ 803

Wed 28/54:45 p.m.YYZ - STL

2 stops26h 36mAlaska Airlines

Wed 4/66:00 a.m.STL - YYZ

2 stops32h 00mAlaska Airlines

Deal found 28/4C$ 1,073

Fri 30/53:50 p.m.YOW - STL

1 stop18h 25mMultiple Airlines

Sun 1/65:45 p.m.STL - YOW

1 stop22h 21mMultiple Airlines

Deal found 29/4C$ 563

Wed 23/711:00 a.m.YUL - STL

1 stop10h 57mDelta

Sat 26/79:16 a.m.STL - YUL

1 stop8h 37mDelta

Deal found 29/4C$ 648

Tue 17/66:00 a.m.YUL - STL

1 stop7h 36mAir Canada

Sun 22/61:30 p.m.STL - YUL

Nonstop2h 30mAir Canada

Deal found 29/4C$ 700

Direct flights from Ontario to St. Louis
Explore direct flight options from Ontario to St. Louis based on user searches, and compare prices and availability for your desired travel dates. Data last updated 30 April 2025.

Sat 14/611:30 a.m.YYZ - STL

Nonstop2h 06mAir Canada

Sat 21/67:30 a.m.STL - YYZ

Nonstop1h 55mAir Canada

Deal found 30/4C$ 566

Thu 22/511:30 a.m.YYZ - STL

Nonstop2h 06mMultiple Airlines

Sun 25/57:30 a.m.STL - YYZ

Nonstop1h 55mMultiple Airlines

Deal found 30/4C$ 646

Sat 17/511:30 a.m.YYZ - STL

Nonstop2h 06mUnited Airlines

Tue 3/67:30 a.m.STL - YYZ

Nonstop1h 55mUnited Airlines

Deal found 29/4C$ 734

Tue 17/66:10 p.m.YUL - STL

Nonstop2h 48mUnited Airlines

Sun 22/61:30 p.m.STL - YUL

Nonstop2h 30mUnited Airlines

Deal found 29/4C$ 866

Thu 25/96:10 p.m.YUL - STL

Nonstop2h 47mAir Canada

Mon 29/91:30 p.m.STL - YUL

Nonstop2h 30mAir Canada

Deal found 29/4C$ 901

Wed 23/76:10 p.m.YUL - STL

Nonstop2h 50mMultiple Airlines

Sat 26/71:30 p.m.STL - YUL

Nonstop2h 30mMultiple Airlines

Deal found 29/4C$ 936

Last-minute flights from Ontario to St. Louis
Discover last-minute flight deals from Ontario to St. Louis. Data last updated 30 April 2025 and is based on user searches.

Mon 5/56:45 a.m.YUL - STL

2 stops18h 21mMultiple Airlines

Mon 12/55:45 p.m.STL - YUL

1 stop19h 35mMultiple Airlines

Deal found 28/4C$ 657

Mon 5/54:40 p.m.YUL - STL

2 stops24h 07mUnited Airlines

Mon 12/59:40 a.m.STL - YUL

2 stops11h 10mUnited Airlines

Deal found 28/4C$ 961

Mon 5/510:44 a.m.YUL - STL

1 stop9h 31mAmerican Airlines

Fri 9/57:32 a.m.STL - YUL

1 stop8h 23mAmerican Airlines

Deal found 29/4C$ 1,093

Thu 8/59:50 a.m.YYZ - STL

1 stop15h 16mMultiple Airlines

Tue 13/55:45 p.m.STL - YYZ

1 stop29h 02mMultiple Airlines

Deal found 28/4C$ 576

Thu 8/53:00 p.m.YYZ - STL

1 stop5h 58mAir Canada

Tue 13/57:30 a.m.STL - YYZ

Nonstop1h 55mAir Canada

Deal found 28/4C$ 907

Fri 9/56:05 p.m.YYZ - STL

1 stop3h 44mWestJet

Mon 12/56:00 a.m.STL - YYZ

1 stop5h 14mWestJet

Deal found 28/4C$ 840

Fri 9/511:30 a.m.YYZ - STL

Nonstop2h 06mUnited Airlines

Mon 12/57:30 a.m.STL - YYZ

Nonstop1h 55mUnited Airlines

Deal found 28/4C$ 865

Sat 10/56:30 a.m.YYZ - STL

1 stop27h 45mMultiple Airlines

Mon 12/59:55 p.m.STL - YYZ

1 stop25h 17mMultiple Airlines

Deal found 27/4C$ 498

Thu 15/55:29 p.m.YYZ - STL

1 stop5h 59mWestJet Encore

Mon 19/56:00 p.m.STL - YYZ

1 stop19h 33mWestJet Encore

Deal found 28/4C$ 803

Wed 21/511:30 a.m.YYZ - STL

Nonstop2h 06mAir Canada

Tue 27/58:10 a.m.STL - YYZ

1 stop5h 28mAir Canada

Deal found 28/4C$ 561

Thu 22/56:30 a.m.YYZ - STL

1 stop4h 19mBritish Airways

Sun 25/56:12 a.m.STL - YYZ

2 stops7h 21mBritish Airways

Deal found 29/4C$ 642

Fri 23/56:10 p.m.YUL - STL

Nonstop2h 48mAir Canada

Mon 26/59:50 a.m.STL - YUL

1 stop6h 36mAir Canada

Deal found 29/4C$ 736

One-way flights from Ontario to St. Louis
Search for one-way flight options from Ontario to St. Louis. Find affordable one-way fares based on user searches. Data last updated 30 April 2025.

Sun 25/54:00 p.m.YYZ - STL

1 stop8h 52mMultiple Airlines

Deal found 28/4C$ 260

Sun 18/54:25 p.m.YOW - STL

1 stop8h 41mMultiple Airlines

Deal found 29/4C$ 298

Tue 6/56:45 a.m.YUL - STL

2 stops18h 21mMultiple Airlines

Deal found 29/4C$ 313

Sun 25/56:30 p.m.YYZ - STL

Nonstop2h 13mAir Canada

Deal found 28/4C$ 327

Sun 31/87:00 a.m.YYZ - STL

3 stops14h 46mUnited Airlines

Deal found 28/4C$ 343

Fri 4/76:00 a.m.YUL - STL

1 stop15h 53mDelta

Deal found 29/4C$ 350

Mon 1/96:30 p.m.YYZ - STL

2 stops17h 08mWestJet

Deal found 29/4C$ 381

Mon 2/66:10 p.m.YUL - STL

Nonstop2h 48mAir Canada

Deal found 29/4C$ 385

Fri 13/66:10 p.m.YUL - STL

Nonstop2h 48mUnited Airlines

Deal found 29/4C$ 406

Sat 18/1010:32 a.m.YUL - STL

1 stop10h 05mAmerican Airlines

Deal found 29/4C$ 464

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

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Sat 10/5

6:30 a.m.-9:15 a.m.

1 stop27h 45m

Lambert-St Louis

Mon 12/5

9:55 p.m.-12:12 a.m.

1 stop25h 17m

C$ 498

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Mon 23/6

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

Nonstop2h 06m

Lambert-St Louis

Wed 25/6

7:30 a.m.-10:25 a.m.

Nonstop1h 55m

C$ 561

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Fri 30/5

3:50 p.m.-9:15 a.m.

1 stop18h 25m

Lambert-St Louis

Sun 1/6

5:45 p.m.-5:06 p.m.

1 stop22h 21m

C$ 563

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Fri 30/5

9:49 a.m.-1:19 p.m.

1 stop4h 30m

Lambert-St Louis

Sun 1/6

6:00 a.m.-1:40 p.m.

1 stop6h 40m

C$ 568

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Thu 22/5

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

Nonstop2h 06m

Lambert-St Louis

Sun 25/5

2:30 p.m.-5:30 p.m.

Nonstop2h 00m

C$ 577

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Fri 5/9

6:24 p.m.-11:49 p.m.

1 stop6h 25m

Lambert-St Louis

Sun 7/9

5:29 a.m.-2:55 p.m.

1 stop8h 26m

C$ 580

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Thu 22/5

6:30 a.m.-9:49 a.m.

1 stop4h 19m

Lambert-St Louis

Sun 25/5

6:12 a.m.-2:33 p.m.

2 stops7h 21m

C$ 642

MontrealSt. Louis

YUL - STL

YULSTL

Montreal Pierre Elliott Trudeau Intl

Wed 23/7

11:00 a.m.-8:57 p.m.

1 stop10h 57m

Lambert-St Louis

Sat 26/7

9:16 a.m.-6:53 p.m.

1 stop8h 37m

C$ 648

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Mon 23/6

8:00 p.m.-9:43 a.m.

2 stops14h 43m

Lambert-St Louis

Thu 26/6

10:48 a.m.-5:06 p.m.

1 stop5h 18m

C$ 684

MontrealSt. Louis

YUL - STL

YULSTL

Montreal Pierre Elliott Trudeau Intl

Tue 17/6

6:00 a.m.-12:36 p.m.

1 stop7h 36m

Lambert-St Louis

Sun 22/6

1:30 p.m.-5:00 p.m.

Nonstop2h 30m

C$ 700

Flights are sorted by cheapest round-trip flights first.

Deals found on 28/4

Showing 1-10 of 28 results

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?

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.

Rainfall in St. Louis 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

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

See what other customers who have flown with Alaska Airlines, Delta and United Airlines 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

9,961 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

Alaska Airlines

8.0

Very good

9,961 reviews

Alaska Airlines

8.0

Very good

9,961 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

Delta

8.0

Very good

7,936 reviews

Alaska Airlines

8.0

Very good

9,961 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

United Airlines

7.4

Good

8,696 reviews

Alaska Airlines

8.0

Very good

9,961 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

American Airlines

7.2

Good

10,000 reviews

Alaska Airlines

8.0

Very good

9,961 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

WestJet

7.2

Good

2,823 reviews

Alaska Airlines

8.0

Very good

9,961 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

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.
What are the cheapest airlines to fly from Region of Ontario to St. Louis one-way?
For one-way options, check prices for Air Canada. According to our data, you can fly for as low as C$ 327. Users have also found prices from C$ 343 and C$ 350 on United Airlines and Delta, 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$ 441, our data indicates the cheapest price to be C$ 294. The most popular route (Toronto Pearson Intl - Lambert-St Louis), is priced around C$ 504.
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

Chesterfield

St. Peters

Browse thousands of different options on Cheapflights for your next trip

Alternative routes for Ontario to St. Louis

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Complete your trip

St. Louis car rentals

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Top 3 airlines flying from Ontario to St. Louis

Airline	Cheapest	Average	Flexibility	On-time
Air Canada	CheapestC$ 514	AverageC$ 785	FlexibilityNo cancel fee	On-time67%	Search Air Canada flights
United Airlines	CheapestC$ 546	AverageC$ 679	FlexibilityNo cancel fee	On-time69%	Search United Airlines flights
WestJet	CheapestC$ 611	AverageC$ 755	FlexibilityNo cancel fee	On-time60%	Search WestJet flights

Fly with Cheapflights

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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Cheap flights from Ontario to St. Louis from C$ 241

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 25/5. Fares are subject to change and may not be available on all flights or dates of travel.

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 30 April 2025.

Round-trip from

One-way from

Popular in

Cheapest in

Average price

Good round-trip deal

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Cheapest flights from Ontario to St. LouisExplore 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 30 April 2025.

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 30 April 2025.

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

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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?

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 30 April 2025.

Rainfall in St. Louis by month

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

Temperature in St. Louis by month

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

Reviews of airlines servicing St. Louis

See what other customers who have flown with Alaska Airlines, Delta and United Airlines 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.

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?

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

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

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

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

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

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

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

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

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Alternative routes for Ontario to St. Louis

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Top 3 airlines flying from Ontario to St. Louis

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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 30 April 2025.