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

American Airlines, United 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 66% of people opting to fly with this airline when travelling to St. Louis. Keep in mind that there are 4 different airlines that fly to St. Louis on a routine basis, so you have a few additional options to choose from.

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 06m 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 week?

The number of flights available between Region of Ontario and St. Louis is 42 per week as of June 2026. The most frequent departure day is Mon, with 14% of weekly flights leaving on this day.

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

6 flights are operational daily from Region of Ontario to St. Louis as of June 2026. The most popular departure time for this route is 11:00a.m., with 50% of flights per day taking off at noon.

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 4 as of June 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$ 265 Cheap Flights from Ontario to St. Louis in 2026

Discover deals from 900+ travel sites with momondo.

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.

3:13 p.m. - 12:27 a.m.

YYZ

STL

10h 14m

1 stop

5:00 a.m. - 2:32 p.m.

STL

YYZ

8h 32m

1 stop

C$ 451American Airlines

Wed, 9 Sep - Tue, 22 Sep

1:17 p.m. - 12:15 a.m.

YYZ

STL

11h 58m

1 stop

6:55 a.m. - 5:34 p.m.

STL

YYZ

9h 39m

1 stop

C$ 467American Airlines

Sat, 25 Jul - Wed, 29 Jul

7:17 a.m. - 1:53 p.m.

YYZ

STL

7h 36m

1 stop

6:55 a.m. - 5:34 p.m.

STL

YYZ

9h 39m

1 stop

C$ 481American Airlines

Tue, 21 Jul - Tue, 28 Jul

3:13 p.m. - 12:27 a.m.

YYZ

STL

10h 14m

1 stop

1:49 p.m. - 11:26 p.m.

STL

YYZ

8h 37m

1 stop

C$ 505American Airlines

Mon, 21 Sep - Sat, 26 Sep

10:10 a.m. - 3:30 p.m.

YOW

STL

6h 20m

1 stop

4:15 p.m. - 11:48 p.m.

STL

YOW

6h 33m

1 stop

C$ 541Air Canada

Tue, 27 Oct - Wed, 28 Oct

3:10 p.m. - 11:44 p.m.

YOW

STL

9h 34m

1 stop

6:01 a.m. - 4:38 p.m.

STL

YOW

9h 37m

1 stop

C$ 548United Airlines

Thu, 30 Jul - Mon, 3 Aug

7:00 a.m. - 5:50 p.m.

YYZ

STL

11h 50m

1 stop

6:17 p.m. - 2:05 p.m.

STL

YYZ

18h 48m

2 stops

C$ 550Multiple Airlines

Sat, 22 Aug - Mon, 24 Aug

6:25 a.m. - 11:57 a.m.

YOW

STL

6h 32m

1 stop

4:53 p.m. - 9:11 a.m.

STL

YOW

15h 18m

1 stop

C$ 587United Airlines

Tue, 22 Sep - Tue, 22 Sep

9:10 a.m. - 3:30 p.m.

YOW

STL

7h 20m

1 stop

4:15 p.m. - 8:18 a.m.

STL

YOW

15h 03m

1 stop

C$ 592Air Canada

Tue, 27 Oct - Fri, 30 Oct

6:00 a.m. - 1:20 p.m.

YUL

STL

8h 20m

1 stop

5:45 p.m. - 11:10 p.m.

STL

YUL

4h 25m

1 stop

C$ 688Delta

Tue, 27 Oct - Wed, 28 Oct

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Delta flights from Region of Ontario to St. Louis

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

Delta

9 Jul

YYZ9:45 a.m.Toronto Pearson Intl

4h 20m

1 stop

STL1:05 p.m.Lambert-St Louis

12 Jul

STL6:30 a.m.Lambert-St Louis

6h 04m

1 stop

YYZ1:34 p.m.Toronto Pearson Intl

C$ 682

Delta

27 Oct

YUL6:00 a.m.Montreal Pierre Elliott Trudeau Intl

8h 20m

1 stop

STL1:20 p.m.Lambert-St Louis

28 Oct

STL5:45 p.m.Lambert-St Louis

4h 25m

1 stop

YUL11:10 p.m.Montreal Pierre Elliott Trudeau Intl

C$ 688

Delta

31 Aug

YUL7:00 a.m.Montreal Pierre Elliott Trudeau Intl

5h 46m

1 stop

STL11:46 a.m.Lambert-St Louis

5 Sep

STL1:04 p.m.Lambert-St Louis

9h 48m

1 stop

YUL11:52 p.m.Montreal Pierre Elliott Trudeau Intl

C$ 704

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

27 Oct

YOW10:10 a.m.Ottawa

6h 20m

1 stop

STL3:30 p.m.Lambert-St Louis

28 Oct

STL4:15 p.m.Lambert-St Louis

6h 33m

1 stop

YOW11:48 p.m.Ottawa

C$ 541

Air Canada

27 Oct

YOW9:10 a.m.Ottawa

7h 20m

1 stop

STL3:30 p.m.Lambert-St Louis

30 Oct

STL4:15 p.m.Lambert-St Louis

15h 03m

1 stop

YOW8:18 a.m.Ottawa

C$ 592

Air Canada

27 Oct

YOW9:55 a.m.Ottawa

6h 46m

2 stops

STL3:41 p.m.Lambert-St Louis

28 Oct

STL9:40 a.m.Lambert-St Louis

9h 11m

2 stops

YOW7:51 p.m.Ottawa

C$ 610

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Wed 9/9

3:13 p.m.-12:27 a.m.

1 stop10h 14m

Lambert-St Louis

Tue 22/9

5:00 a.m.-2:32 p.m.

1 stop8h 32m

C$ 451

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Sat 25/7

1:17 p.m.-12:15 a.m.

1 stop11h 58m

Lambert-St Louis

Wed 29/7

6:55 a.m.-5:34 p.m.

1 stop9h 39m

C$ 467

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Tue 21/7

7:17 a.m.-1:53 p.m.

1 stop7h 36m

Lambert-St Louis

Tue 28/7

6:55 a.m.-5:34 p.m.

1 stop9h 39m

C$ 481

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Mon 21/9

3:13 p.m.-12:27 a.m.

1 stop10h 14m

Lambert-St Louis

Sat 26/9

1:49 p.m.-11:26 p.m.

1 stop8h 37m

C$ 505

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 27/10

10:10 a.m.-3:30 p.m.

1 stop6h 20m

Lambert-St Louis

Wed 28/10

4:15 p.m.-11:48 p.m.

1 stop6h 33m

C$ 541

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Thu 30/7

3:10 p.m.-11:44 p.m.

1 stop9h 34m

Lambert-St Louis

Mon 3/8

6:01 a.m.-4:38 p.m.

1 stop9h 37m

C$ 548

TorontoSt. Louis

YYZ - STL

YYZSTL

Toronto Pearson Intl

Sat 22/8

7:00 a.m.-5:50 p.m.

1 stop11h 50m

Lambert-St Louis

Mon 24/8

6:17 p.m.-2:05 p.m.

2 stops18h 48m

C$ 550

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 22/9

6:25 a.m.-11:57 a.m.

1 stop6h 32m

Lambert-St Louis

Tue 22/9

4:53 p.m.-9:11 a.m.

1 stop15h 18m

C$ 587

OttawaSt. Louis

YOW - STL

YOWSTL

Ottawa

Tue 27/10

9:10 a.m.-3:30 p.m.

1 stop7h 20m

Lambert-St Louis

Fri 30/10

4:15 p.m.-8:18 a.m.

1 stop15h 03m

C$ 592

Quickest round-trip

MontrealSt. Louis

YUL - STL

YULSTL

Montreal Pierre Elliott Trudeau Intl

Tue 27/10

6:00 a.m.-1:20 p.m.

1 stop8h 20m

Lambert-St Louis

Wed 28/10

5:45 p.m.-11:10 p.m.

1 stop4h 25m

C$ 688

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 December is, on average, the cheapest month to fly to St. Louis from Region of Ontario, with most prices found around C$ 238. 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$ 248.

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$ 601. The most expensive day to fly to St. Louis is Monday, with ticket prices averaging around C$ 1,015.

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 at noon when flights can be purchased for as low as C$ 642. If you have a flexible travel schedule, then try to avoid flying in the evening when prices are C$ 1,025 on average. Flights to St. Louis from Region of Ontario in the evening 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$ 739 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$ 509 on momondo.

What cabin class options are available on Region of Ontario to St. Louis flights?

There is only 1 cabin class available to choose from on Region of Ontario to 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?

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$ 384
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$ 384. The best round-trip flight deal from Region of Ontario to St. Louis found on momondo in the last 72 hours is C$ 596.

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 4 as of June 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 Canadair (Bombardier) Regional Jet 900, representing 57.86% of all bookings. The subsequent popular models are Airbus A220-300 at 29.29%, Embraer 175 at 9.29%, and Boeing 737 MAX 8 at 1.43%.

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
Air Canada	PriceFrom C$ 341	Free Cancellation	Rating 7.1 11,251 reviews	Search Air Canada flights
United Airlines	PriceFrom C$ 347	Free Cancellation	Rating 7.4 9,884 reviews	Search United Airlines flights
American Airlines	PriceFrom C$ 375	Free Cancellation	Rating 7.1 11,752 reviews	Search American Airlines flights
WestJet	PriceFrom C$ 645	Free Cancellation	Rating 7.2 3,384 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$ 265

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 12/9. 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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Delta flights from Region of Ontario to St. Louis

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

Air Canada flights from Region of Ontario to St. Louis

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

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Use the filters below to find and compare flights from Ontario to St. Louis that are best for you.

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?

What cabin class options are available on Region of Ontario to 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

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

Airports servicing Missouri

Fly your favourite airline to St. Louis

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