How many flights depart from Region of Ontario to St. Louis on average per week?

The number of flights available between Region of Ontario and St. Louis is 40 per week as of May 2026. The most frequent departure day is Mon, with 15% of weekly flights leaving on this day.

How long does it take to fly to St. Louis?

Flight times vary depending on what airport in Region of Ontario you fly out of and what airport in St. Louis you fly into. For example, flying from Toronto to St. Louis takes 2h 06m on average. On the other hand, flying from Ottawa to St. Louis takes 5h 09m on average. Keep in mind that it’s always quicker to opt for a non-stop flight, so be sure to check momondo to see if there are any available for your route.

What is the cheapest airline that flies from Ontario to Lambert-St Louis?

Air Canada, United Airlines, and American Airlines are the most popular carriers operating from Ontario to Lambert-St Louis

How many flights depart from Region of Ontario to St. Louis on average per day?

5 flights are operational daily from Region of Ontario to St. Louis as of May 2026. The most popular departure time for this route is 7:00p.m., with 63% of flights per day taking off in the evening.

Which airlines fly to St. Louis?

Air Canada, United Airlines and American Airlines are the top three most popular airlines that fly to St. Louis from Region of Ontario according to our data. Air Canada is the first choice among our users, with 66% of people opting to fly with this airline when travelling to St. Louis. Keep in mind that there are 5 different airlines that fly to St. Louis on a routine basis, so you have a few additional options to choose from.

When did momondo last update prices for flights from Ontario to Lambert-St Louis Airport?

Prices for flights from Ontario to Lambert-St Louis Airport are refreshed on a daily basis.

How many operators does momondo search for flights from Ontario to Lambert-St Louis Airport?

The number of operators available for flights from Ontario to Lambert-St Louis Airport is 5 as of May 2026.

How old do you have to be to fly from Ontario to Lambert-St Louis Airport?

The minimum age a child must be to fly alone is five but airlines that offer an unaccompanied minor (UNMR) service will have their own age restrictions, including rules around flight length, timings, and stopovers. We always recommend checking with the individual airline you are booking with to travel from Ontario to Lambert-St Louis Airport.

What documentation or ID do you need to fly to Lambert-St Louis Airport?

The travel and health documents you'll need for your trip to Lambert-St Louis Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at Lambert-St Louis Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

C$ 251 Cheap Flights from Ontario to St. Louis in 2026

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Find the cheapest flights from Ontario to St. Louis

Round-trip

One-way

Last minute

Direct

Cheap round-trip flights

Enter your travel dates to find the best prices.

2:40 p.m. - 8:25 p.m.

YOW

STL

6h 45m

1 stop

7:05 a.m. - 1:05 p.m.

STL

YOW

5h 00m

1 stop

C$ 507Air Canada

Sat, 23 May - Sun, 24 May

5:25 p.m. - 9:21 p.m.

YOW

STL

4h 56m

1 stop

6:00 a.m. - 9:35 p.m.

STL

YOW

14h 35m

1 stop

C$ 508United Airlines

Tue, 2 Jun - Wed, 3 Jun

7:25 a.m. - 4:33 p.m.

YYZ

STL

10h 08m

1 stop

2:32 p.m. - 11:29 p.m.

STL

YYZ

7h 57m

1 stop

C$ 508American Airlines

Wed, 17 Jun - Wed, 24 Jun

2:52 p.m. - 9:21 p.m.

YOW

STL

7h 29m

2 stops

6:00 a.m. - 4:38 p.m.

STL

YOW

9h 38m

1 stop

C$ 510United Airlines

Tue, 2 Jun - Wed, 3 Jun

9:50 a.m. - 11:57 p.m.

YYZ

STL

15h 07m

1 stop

5:06 p.m. - 2:05 p.m.

STL

YYZ

19h 59m

2 stops

C$ 511Multiple Airlines

Tue, 26 May - Wed, 10 Jun

2:40 p.m. - 8:25 p.m.

YOW

STL

6h 45m

1 stop

7:05 a.m. - 1:05 p.m.

STL

YOW

5h 00m

1 stop

C$ 518Air Canada

Tue, 19 May - Sat, 23 May

7:25 a.m. - 2:02 p.m.

YYZ

STL

7h 37m

1 stop

7:03 a.m. - 5:44 p.m.

STL

YYZ

9h 41m

1 stop

C$ 519American Airlines

Tue, 9 Jun - Wed, 10 Jun

6:00 a.m. - 9:30 p.m.

YOW

STL

16h 30m

2 stops

12:55 p.m. - 6:48 p.m.

STL

YOW

4h 53m

1 stop

C$ 540United Airlines

Wed, 3 Jun - Sat, 6 Jun

6:51 p.m. - 11:59 p.m.

YUL

STL

6h 08m

1 stop

5:20 p.m. - 11:57 p.m.

STL

YUL

5h 37m

1 stop

C$ 626Delta

Fri, 29 May - Mon, 1 Jun

12:49 p.m. - 9:09 p.m.

YUL

STL

9h 20m

1 stop

6:04 p.m. - 11:13 p.m.

STL

YUL

4h 09m

1 stop

C$ 627Delta

Sun, 24 May - Sat, 30 May

United Airlines flights from Region of Ontario to St. Louis

Our best United Airlines deals on Region of Ontario to St. Louis flight tickets

United Airlines

2 Jun

YOW5:25 p.m.Ottawa

4h 56m

1 stop

STL9:21 p.m.Lambert-St Louis

3 Jun

STL6:00 a.m.Lambert-St Louis

14h 35m

1 stop

YOW9:35 p.m.Ottawa

C$ 508

United Airlines

2 Jun

YOW2:52 p.m.Ottawa

7h 29m

2 stops

STL9:21 p.m.Lambert-St Louis

3 Jun

STL6:00 a.m.Lambert-St Louis

9h 38m

1 stop

YOW4:38 p.m.Ottawa

C$ 510

United Airlines

3 Jun

YOW6:00 a.m.Ottawa

16h 30m

2 stops

STL9:30 p.m.Lambert-St Louis

6 Jun

STL12:55 p.m.Lambert-St Louis

4h 53m

1 stop

YOW6:48 p.m.Ottawa

C$ 540

Air Canada flights from Region of Ontario to St. Louis

Our best Air Canada deals on Region of Ontario to St. Louis flight tickets

Air Canada

23 May

YOW2:40 p.m.Ottawa

6h 45m

1 stop

STL8:25 p.m.Lambert-St Louis

24 May

STL7:05 a.m.Lambert-St Louis

5h 00m

1 stop

YOW1:05 p.m.Ottawa

C$ 507

Air Canada

19 May

YOW2:40 p.m.Ottawa

6h 45m

1 stop

STL8:25 p.m.Lambert-St Louis

23 May

STL7:05 a.m.Lambert-St Louis

5h 00m

1 stop

YOW1:05 p.m.Ottawa

C$ 518

Air Canada

1 Oct

YOW10:00 a.m.Ottawa

5h 00m

1 stop

STL2:00 p.m.Lambert-St Louis

6 Oct

STL8:55 a.m.Lambert-St Louis

5h 15m

1 stop

YOW3:10 p.m.Ottawa

C$ 556

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

Quickest round-trip

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Sat 23/5

2:40 p.m.-8:25 p.m.

1 stop6h 45m

Lambert-St Louis

Sun 24/5

7:05 a.m.-1:05 p.m.

1 stop5h 00m

C$ 507

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 2/6

5:25 p.m.-9:21 p.m.

1 stop4h 56m

Lambert-St Louis

Wed 3/6

6:00 a.m.-9:35 p.m.

1 stop14h 35m

C$ 508

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Wed 17/6

7:25 a.m.-4:33 p.m.

1 stop10h 08m

Lambert-St Louis

Wed 24/6

2:32 p.m.-11:29 p.m.

1 stop7h 57m

C$ 508

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 2/6

2:52 p.m.-9:21 p.m.

2 stops7h 29m

Lambert-St Louis

Wed 3/6

6:00 a.m.-4:38 p.m.

1 stop9h 38m

C$ 510

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Tue 26/5

9:50 a.m.-11:57 p.m.

1 stop15h 07m

Lambert-St Louis

Wed 10/6

5:06 p.m.-2:05 p.m.

2 stops19h 59m

C$ 511

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 19/5

2:40 p.m.-8:25 p.m.

1 stop6h 45m

Lambert-St Louis

Sat 23/5

7:05 a.m.-1:05 p.m.

1 stop5h 00m

C$ 518

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Tue 9/6

7:25 a.m.-2:02 p.m.

1 stop7h 37m

Lambert-St Louis

Wed 10/6

7:03 a.m.-5:44 p.m.

1 stop9h 41m

C$ 519

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 3/6

6:00 a.m.-9:30 p.m.

2 stops16h 30m

Lambert-St Louis

Sat 6/6

12:55 p.m.-6:48 p.m.

1 stop4h 53m

C$ 540

MontrealSt. Louis

YUL - STL

YULSTL

Montreal Pierre Elliott Trudeau Intl

Fri 29/5

6:51 p.m.-11:59 p.m.

1 stop6h 08m

Lambert-St Louis

Mon 1/6

5:20 p.m.-11:57 p.m.

1 stop5h 37m

C$ 626

MontrealSt. Louis

YUL - STL

YULSTL

Montreal Pierre Elliott Trudeau Intl

Sun 24/5

12:49 p.m.-9:09 p.m.

1 stop9h 20m

Lambert-St Louis

Sat 30/5

6:04 p.m.-11:13 p.m.

1 stop4h 09m

C$ 627

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How to get the cheapest flight ticket from Region of Ontario to St. Louis

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

Prices

Airlines

Other information

What is the cheapest month to fly to St. Louis?

The month of December is, on average, the cheapest month to fly to St. Louis from Region of Ontario, with most prices found around C$ 230. If you don’t want to visit St. Louis in December, then you should wait until October to fly from Region of Ontario, when ticket prices are also cheap, with an average price of C$ 239.

What is the cheapest day to depart on your flight to St. Louis?

Our data shows that Saturday is the least expensive day to fly to St. Louis. Tickets to fly out on this day can be as low as C$ 577. The most expensive day to fly to St. Louis is Monday, with ticket prices averaging around C$ 978.

What is the cheapest time of day to depart on your flight to St. Louis?

The cheapest time of day to fly to St. Louis is in the morning when flights can be purchased for as low as C$ 574. If you have a flexible travel schedule, then try to avoid flying in the afternoon when prices are C$ 710 on average. Flights to St. Louis from Region of Ontario in the afternoon are generally more expensive because this time of day is more convenient for travellers’ schedules.

What is the cheapest Ontario to Lambert-St Louis flight route?

Fly from Toronto Pearson Intl to Lambert-St Louis for the best Ontario - Lambert-St Louis flight prices

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

You are more likely to see cheaper flights to St. Louis from Region of Ontario when booking weeks ahead of your departure date. In general, you can expect to find flights to St. Louis for around C$ 669 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to St. Louis from Region of Ontario for as low as C$ 491 on momondo.

Can stopping save me money on Region of Ontario to St. Louis flights?

No. A direct flight is the cheapest option for a flight between Region of Ontario to St. Louis.

Cheap Region of Ontario to St. Louis flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Region of Ontario to St. Louis

Best price found	C$ 323
Fastest flight time	2h 06m
Direct flights	Every day
Airports in St. Louis	1 airport

The best one-way flight to St. Louis from Region of Ontario in the past 72 hours is C$ 323. The best round-trip flight deal from Region of Ontario to St. Louis found on momondo in the last 72 hours is C$ 658.

The fastest flight from Region of Ontario to St. Louis takes 2h 06m

Direct flights go from Region of Ontario to St. Louis every day.

There is 1 airport in St. Louis. From Region of Ontario there are direct flights to Lambert-St Louis (STL).

Search flight deals

Frequently asked questions about flying from Ontario to St. Louis

When did momondo last update prices for flights from Ontario to Lambert-St Louis Airport?
Prices for flights from Ontario to Lambert-St Louis Airport are refreshed on a daily basis.
How many operators does momondo search for flights from Ontario to Lambert-St Louis Airport?
The number of operators available for flights from Ontario to Lambert-St Louis Airport is 5 as of May 2026.
How old do you have to be to fly from Ontario to Lambert-St Louis Airport?
The minimum age a child must be to fly alone is five but airlines that offer an unaccompanied minor (UNMR) service will have their own age restrictions, including rules around flight length, timings, and stopovers. We always recommend checking with the individual airline you are booking with to travel from Ontario to Lambert-St Louis Airport.
What documentation or ID do you need to fly to Lambert-St Louis Airport?
The travel and health documents you'll need for your trip to Lambert-St Louis Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at Lambert-St Louis Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.
What is the most popular plane model from Region of Ontario to St. Louis?
momondo data reveals that the most frequently booked plane model on the route from Region of Ontario to St. Louis is Embraer 175, representing 48.33% of all bookings. The subsequent popular models are Canadair (Bombardier) Regional Jet 900 at 21.67%, Airbus A220-300 at 15.83%, and Airbus A319 at 5.00%.

Best airlines flying from Region of Ontario to St. Louis

Compare and see reviews for airlines that fly from Region of Ontario to St. Louis with momondo

Airline	Rating	Free Cancellation	Price
United Airlines	PriceFrom C$ 334	Free Cancellation	Rating 7.4 9,695 reviews	Search United Airlines flights
American Airlines	PriceFrom C$ 361	Free Cancellation	Rating 7.1 11,668 reviews	Search American Airlines flights
Air Canada	PriceFrom C$ 402	Free Cancellation	Rating 7.1 11,008 reviews	Search Air Canada flights
Delta	PriceFrom C$ 469	Free Cancellation	Rating 7.9 8,457 reviews	Search Delta flights
WestJet	PriceFrom C$ 552	Free Cancellation	Rating 7.2 3,332 reviews	Search WestJet flights

Why use momondo?

Why should I use momondo to find a flight deal from Ontario to St. Louis?

It is quick and easy to find Ontario to St. Louis flights on momondo. We search and return numerous flight options from various airlines and agents. You can then use our filters to narrow your search until you have found the most convenient flight to St. Louis that suits you.

Can I find flights from Ontario to St. Louis with flexible booking policies on momondo?

Flights from Ontario to St. Louis with flexible booking policies can be found by using the search form above and then selecting our dedicated flexible booking filter, which will highlight only the flights where this policy is applied.

How can momondo help me find flights from Ontario to St. Louis?

Once you have performed a search for Ontario to St. Louis flights, momondo helps you find the right one by offering useful filters to narrow down your flight selection. Flights can be filtered by multiple factors such as airline, airport and price; but also by other criteria like aircraft type and payment method.

I’m not ready to book a flight from Ontario to St. Louis right now. Can momondo alert me if prices change?

Yes momondo offers price alerts on flights to St. Louis from Ontario. After performing a search on this page you should be able to see the price alert set up feature. Simply provide a valid email address and momondo will instantly alert you when prices change.

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Cheap flights from Ontario to St. Louis from C$ 251

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Ontario to St. Louis departing on 2/6. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.

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United Airlines flights from Region of Ontario to St. Louis

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See travel insights to St. Louis from

How to get the cheapest flight ticket from Region of Ontario to St. Louis

What is the cheapest month to fly to St. Louis?

What is the cheapest day to depart on your flight to St. Louis?

What is the cheapest time of day to depart on your flight to St. Louis?

What is the cheapest Ontario to Lambert-St Louis flight route?

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

Can stopping save me money on Region of Ontario to St. Louis flights?

What is the cheapest airline that flies from Ontario to Lambert-St Louis?

Which airlines fly to St. Louis?

How many flights depart from Region of Ontario to St. Louis on average per day?

How many flights depart from Region of Ontario to St. Louis on average per week?

How long does it take to fly to St. Louis?

Cheap Region of Ontario to St. Louis flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Region of Ontario to St. Louis

Best price found

Fastest flight time

Direct flights

Airports in St. Louis

Frequently asked questions about flying from Ontario to St. Louis

Best airlines flying from Region of Ontario to St. Louis

Compare and see reviews for airlines that fly from Region of Ontario to St. Louis with momondo

Why use momondo?

An easier way to manage your St. Louis trip

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.

Find better results for your trip to the United States

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Fly your favourite airline to St. Louis

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