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 12 per week as of March 2026. The most frequent departure day is Mon, with 17% 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 6h 46m 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.

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

1 flights are operational daily from Region of Ontario to St. Louis as of March 2026. The most popular departure time for this route is 2:00p.m., with 100% of flights per day taking off in the afternoon.

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

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

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 72% 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 March 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$ 253 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.

6:25 a.m. - 3:46 p.m.

YOW

STL

10h 21m

1 stop

6:00 a.m. - 1:59 p.m.

STL

YOW

6h 59m

1 stop

C$ 418United Airlines

Mon, 25 May - Fri, 29 May

5:25 p.m. - 9:13 p.m.

YOW

STL

4h 48m

1 stop

6:30 a.m. - 9:35 p.m.

STL

YOW

14h 05m

1 stop

C$ 424United Airlines

Tue, 5 May - Wed, 6 May

5:50 p.m. - 11:57 p.m.

YOW

STL

7h 07m

1 stop

11:15 a.m. - 11:54 p.m.

STL

YOW

11h 39m

2 stops

C$ 425United Airlines

Fri, 1 May - Tue, 5 May

12:30 p.m. - 10:19 p.m.

YUL

STL

10h 49m

1 stop

8:03 p.m. - 11:44 a.m.

STL

YUL

14h 41m

1 stop

C$ 433American Airlines

Tue, 5 May - Tue, 12 May

9:15 a.m. - 3:25 p.m.

YOW

STL

7h 10m

1 stop

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

STL

YOW

5h 00m

1 stop

C$ 439Air Canada

Wed, 15 Apr - Wed, 20 May

11:40 a.m. - 8:30 p.m.

YYZ

STL

9h 50m

1 stop

6:00 a.m. - 2:30 p.m.

STL

YYZ

7h 30m

1 stop

C$ 476American Airlines

Wed, 27 May - Wed, 10 Jun

6:05 a.m. - 3:46 p.m.

YOW

STL

10h 41m

2 stops

6:00 a.m. - 2:17 p.m.

STL

YOW

7h 17m

2 stops

C$ 498United Airlines

Tue, 26 May - Thu, 28 May

6:15 a.m. - 11:56 a.m.

YYZ

STL

6h 41m

1 stop

6:25 a.m. - 4:15 p.m.

STL

YYZ

8h 50m

1 stop

C$ 598Delta

Thu, 16 Apr - Tue, 21 Apr

6:10 a.m. - 9:42 a.m.

YYZ

STL

4h 32m

1 stop

5:35 p.m. - 11:10 p.m.

STL

YYZ

4h 35m

1 stop

C$ 602Delta

Tue, 14 Apr - Wed, 15 Apr

2:00 p.m. - 9:13 p.m.

YOW

STL

8h 13m

2 stops

7:45 a.m. - 5:07 p.m.

STL

YOW

8h 22m

1 stop

C$ 641Air Canada

Tue, 5 May - Wed, 6 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

25 May

YOW6:25 a.m.Ottawa

10h 21m

1 stop

STL3:46 p.m.Lambert-St Louis

29 May

STL6:00 a.m.Lambert-St Louis

6h 59m

1 stop

YOW1:59 p.m.Ottawa

C$ 418

United Airlines

5 May

YOW5:25 p.m.Ottawa

4h 48m

1 stop

STL9:13 p.m.Lambert-St Louis

6 May

STL6:30 a.m.Lambert-St Louis

14h 05m

1 stop

YOW9:35 p.m.Ottawa

C$ 424

United Airlines

1 May

YOW5:50 p.m.Ottawa

7h 07m

1 stop

STL11:57 p.m.Lambert-St Louis

5 May

STL11:15 a.m.Lambert-St Louis

11h 39m

2 stops

YOW11:54 p.m.Ottawa

C$ 425

American Airlines flights from Region of Ontario to St. Louis

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

American Airlines

5 May

YUL12:30 p.m.Montreal Pierre Elliott Trudeau Intl

10h 49m

1 stop

STL10:19 p.m.Lambert-St Louis

12 May

STL8:03 p.m.Lambert-St Louis

14h 41m

1 stop

YUL11:44 a.m.Montreal Pierre Elliott Trudeau Intl

C$ 433

American Airlines

27 May

YYZ11:40 a.m.Toronto Pearson Intl

9h 50m

1 stop

STL8:30 p.m.Lambert-St Louis

10 Jun

STL6:00 a.m.Lambert-St Louis

7h 30m

1 stop

YYZ2:30 p.m.Toronto Pearson Intl

C$ 476

American Airlines

15 Apr

YYZ3:13 p.m.Toronto Pearson Intl

9h 33m

1 stop

STL11:46 p.m.Lambert-St Louis

22 Apr

STL5:51 a.m.Lambert-St Louis

10h 52m

1 stop

YYZ5:43 p.m.Toronto Pearson Intl

C$ 512

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Mon 25/5

6:25 a.m.-3:46 p.m.

1 stop10h 21m

Lambert-St Louis

Fri 29/5

6:00 a.m.-1:59 p.m.

1 stop6h 59m

C$ 418

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 5/5

5:25 p.m.-9:13 p.m.

1 stop4h 48m

Lambert-St Louis

Wed 6/5

6:30 a.m.-9:35 p.m.

1 stop14h 05m

C$ 424

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Fri 1/5

5:50 p.m.-11:57 p.m.

1 stop7h 07m

Lambert-St Louis

Tue 5/5

11:15 a.m.-11:54 p.m.

2 stops11h 39m

C$ 425

MontrealSt. Louis

YUL - STL

YULSTL

Montreal Pierre Elliott Trudeau Intl

Tue 5/5

12:30 p.m.-10:19 p.m.

1 stop10h 49m

Lambert-St Louis

Tue 12/5

8:03 p.m.-11:44 a.m.

1 stop14h 41m

C$ 433

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Wed 15/4

9:15 a.m.-3:25 p.m.

1 stop7h 10m

Lambert-St Louis

Wed 20/5

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

1 stop5h 00m

C$ 439

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Wed 27/5

11:40 a.m.-8:30 p.m.

1 stop9h 50m

Lambert-St Louis

Wed 10/6

6:00 a.m.-2:30 p.m.

1 stop7h 30m

C$ 476

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 26/5

6:05 a.m.-3:46 p.m.

2 stops10h 41m

Lambert-St Louis

Thu 28/5

6:00 a.m.-2:17 p.m.

2 stops7h 17m

C$ 498

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Thu 16/4

6:15 a.m.-11:56 a.m.

1 stop6h 41m

Lambert-St Louis

Tue 21/4

6:25 a.m.-4:15 p.m.

1 stop8h 50m

C$ 598

Quickest round-trip

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Tue 14/4

6:10 a.m.-9:42 a.m.

1 stop4h 32m

Lambert-St Louis

Wed 15/4

5:35 p.m.-11:10 p.m.

1 stop4h 35m

C$ 602

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 5/5

2:00 p.m.-9:13 p.m.

2 stops8h 13m

Lambert-St Louis

Wed 6/5

7:45 a.m.-5:07 p.m.

1 stop8h 22m

C$ 641

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first

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 June is, on average, the cheapest month to fly to St. Louis from Region of Ontario, with most prices found around C$ 494. If you don’t want to visit St. Louis in June, then you should wait until January to fly from Region of Ontario, when ticket prices are also cheap, with an average price of C$ 543.

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$ 569. The most expensive day to fly to St. Louis is Monday, with ticket prices averaging around C$ 809.

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$ 540. If you have a flexible travel schedule, then try to avoid flying at noon when prices are C$ 622 on average. Flights to St. Louis from Region of Ontario at noon 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 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$ 632 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$ 490 on momondo.

What cabin class options are available on Ontario to Lambert-St Louis flights?

There is only 1 cabin class available to choose from on Ontario to Lambert-St Louis flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

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

You could potentially save up to 29% on your flight if you consider stops on a Region of Ontario to St. Louis flight.

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$ 975
Fastest flight time	2h 06m
Direct flights	Every day
Airports in St. Louis	1 airport

The best flight deal from Region of Ontario to St. Louis found on momondo in the last 72 hours is C$ 975

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

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 March 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 74.82% of all bookings. The subsequent popular models are Canadair (Bombardier) Regional Jet 900 at 7.19%, Airbus A220-300 at 6.47%, and Airbus A319 at 4.32%.

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$ 331	Free Cancellation	Rating 7.4 9,477 reviews	Search United Airlines flights
American Airlines	PriceFrom C$ 363	Free Cancellation	Rating 7.1 11,494 reviews	Search American Airlines flights
Air Canada	PriceFrom C$ 457	Free Cancellation	Rating 7.1 10,838 reviews	Search Air Canada flights
Delta	PriceFrom C$ 472	Free Cancellation	Rating 7.9 8,326 reviews	Search Delta flights
WestJet	PriceFrom C$ 555	Free Cancellation	Rating 7.2 3,301 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$ 253

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 6/5. 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

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

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

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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 to St. Louis?

What cabin class options are available on Ontario to Lambert-St Louis flights?

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

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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