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

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

What airlines fly to Region of Ontario?

Air Canada, United Airlines and American Airlines are the top three most popular airlines that fly to Region of Ontario from St. Louis according to our data. Air Canada is the first choice among our users, with 68% of people opting to fly with this airline when traveling to Region of Ontario. Keep in mind that there are 3 different airlines that fly to Region of Ontario on a routine basis, so you have a few additional options to choose from.

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

6 flights are operational daily from St. Louis to Region of Ontario as of July 2026. The most popular departure time for this route is 8:00AM, with 50% of flights per day taking off at noon.

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

As of July 2026, there are 42 flights per week flying from St. Louis to Region of Ontario. The most common day of the week flights depart is Mon, with 14% of flights taking off on this day.

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

Prices for flights from Lambert-St Louis Airport to Ontario were last updated today.

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

The number of operators available for flights from Lambert-St Louis Airport to Ontario is 3 as of July 2026.

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

The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Lambert-St Louis Airport to Ontario.

What documentation or ID do you need to fly to Ontario?

The required travel and health documents for your Ontario trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Ontario. We recommend that you seek guidance from your airline or a reliable third party such as IATA.

$144 Cheap Flights from St. Louis to Ontario in 2026

Discover deals from 900+ travel sites with momondo.

Find the cheapest flights from St. Louis to Ontario

Round-trip

One-way

Last minute

Direct

Cheap round-trip flights

Enter your travel dates to find the best prices.

5:00 am - 2:33 pm

STL

YYZ

8h 33m

1 stop

3:13 pm - 12:27 am

YYZ

STL

10h 14m

1 stop

$355American Airlines

Sat, Sep 5 - Sat, Sep 12

7:27 am - 5:44 pm

STL

YYZ

9h 17m

1 stop

6:30 am - 1:16 pm

YYZ

STL

7h 46m

1 stop

$365American Airlines

Thu, Sep 17 - Mon, Sep 21

9:32 am - 6:30 pm

STL

YYZ

7h 58m

1 stop

6:30 am - 1:16 pm

YYZ

STL

7h 46m

1 stop

$371American Airlines

Tue, Sep 8 - Tue, Sep 15

5:00 am - 2:32 pm

STL

YYZ

8h 32m

1 stop

6:30 am - 1:16 pm

YYZ

STL

7h 46m

1 stop

$372American Airlines

Sat, Sep 19 - Thu, Sep 24

9:32 am - 6:30 pm

STL

YYZ

7h 58m

1 stop

1:15 pm - 11:58 pm

YYZ

STL

11h 43m

1 stop

$378American Airlines

Wed, Aug 26 - Sat, Sep 5

10:35 am - 8:55 pm

STL

YYZ

33h 20m

2 stops

7:45 am - 7:39 pm

YYZ

STL

12h 54m

1 stop

$388Multiple Airlines

Thu, Oct 8 - Mon, Oct 12

10:35 am - 11:35 pm

STL

YYZ

12h 00m

2 stops

7:45 am - 7:39 pm

YYZ

STL

12h 54m

1 stop

$415Multiple Airlines

Fri, Oct 9 - Mon, Oct 12

12:10 pm - 7:45 pm

STL

YOW

6h 35m

1 stop

2:35 pm - 6:42 pm

YOW

STL

5h 07m

1 stop

$671Air Canada

Wed, Aug 12 - Wed, Aug 19

8:55 am - 3:10 pm

STL

YOW

5h 15m

1 stop

3:10 pm - 6:42 pm

YOW

STL

4h 32m

1 stop

$675Air Canada

Tue, Sep 1 - Sat, Sep 5

8:50 am - 9:35 pm

STL

YOW

11h 45m

1 stop

6:25 am - 12:02 pm

YOW

STL

6h 37m

1 stop

$678United Airlines

Thu, Sep 3 - Mon, Sep 7

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American Airlines flights from St. Louis to Region of Ontario

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

American Airlines

Sep 5

STL5:00 amLambert-St Louis

8h 33m

1 stop

YYZ2:33 pmToronto Pearson Intl

Sep 12

YYZ3:13 pmToronto Pearson Intl

10h 14m

1 stop

STL12:27 amLambert-St Louis

$355

American Airlines

Sep 17

STL7:27 amLambert-St Louis

9h 17m

1 stop

YYZ5:44 pmToronto Pearson Intl

Sep 21

YYZ6:30 amToronto Pearson Intl

7h 46m

1 stop

STL1:16 pmLambert-St Louis

$365

American Airlines

Sep 8

STL9:32 amLambert-St Louis

7h 58m

1 stop

YYZ6:30 pmToronto Pearson Intl

Sep 15

YYZ6:30 amToronto Pearson Intl

7h 46m

1 stop

STL1:16 pmLambert-St Louis

$371

WestJet flights from St. Louis to Region of Ontario

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

WestJet

Sep 11

STL6:00 amLambert-St Louis

22h 45m

2 stops

YYZ5:45 amToronto Pearson Intl

Sep 12

YYZ9:45 amToronto Pearson Intl

6h 29m

1 stop

STL3:14 pmLambert-St Louis

$477

WestJet

Aug 28

STL12:52 pmLambert-St Louis

17h 03m

2 stops

YYZ6:55 amToronto Pearson Intl

Aug 30

YYZ6:00 amToronto Pearson Intl

6h 46m

1 stop

STL11:46 amLambert-St Louis

$501

WestJet

Aug 8

STL5:33 pmLambert-St Louis

15h 52m

1 stop

YYZ10:25 amToronto Pearson Intl

Aug 10

YYZ6:15 amToronto Pearson Intl

18h 11m

1 stop

STL11:26 pmLambert-St Louis

$617

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Sat 9/5

5:00 am-2:33 pm

1 stop8h 33m

Toronto Pearson Intl

Sat 9/12

3:13 pm-12:27 am

1 stop10h 14m

$355

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Thu 9/17

7:27 am-5:44 pm

1 stop9h 17m

Toronto Pearson Intl

Mon 9/21

6:30 am-1:16 pm

1 stop7h 46m

$365

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Tue 9/8

9:32 am-6:30 pm

1 stop7h 58m

Toronto Pearson Intl

Tue 9/15

6:30 am-1:16 pm

1 stop7h 46m

$371

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Sat 9/19

5:00 am-2:32 pm

1 stop8h 32m

Toronto Pearson Intl

Thu 9/24

6:30 am-1:16 pm

1 stop7h 46m

$372

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Wed 8/26

9:32 am-6:30 pm

1 stop7h 58m

Toronto Pearson Intl

Sat 9/5

1:15 pm-11:58 pm

1 stop11h 43m

$378

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Thu 10/8

10:35 am-8:55 pm

2 stops33h 20m

Toronto Pearson Intl

Mon 10/12

7:45 am-7:39 pm

1 stop12h 54m

$388

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Fri 10/9

10:35 am-11:35 pm

2 stops12h 00m

Toronto Pearson Intl

Mon 10/12

7:45 am-7:39 pm

1 stop12h 54m

$415

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Wed 8/12

12:10 pm-7:45 pm

1 stop6h 35m

Ottawa

Wed 8/19

2:35 pm-6:42 pm

1 stop5h 07m

$671

Quickest round-trip

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Tue 9/1

8:55 am-3:10 pm

1 stop5h 15m

Ottawa

Sat 9/5

3:10 pm-6:42 pm

1 stop4h 32m

$675

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Thu 9/3

8:50 am-9:35 pm

1 stop11h 45m

Ottawa

Mon 9/7

6:25 am-12:02 pm

1 stop6h 37m

$678

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 St. Louis to Region of Ontario

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 Region of Ontario?

The month of March is, on average, the cheapest month to fly to Region of Ontario from St. Louis, with most prices found around $425. If you aren’t able to travel during the month of March, then book flights to Region of Ontario from St. Louis during December instead. Flights to Region of Ontario in December, while not as cheap as those in March, still average around $473.

What is the cheapest day to depart on your flight to Region of Ontario?

According to our data, Friday is the cheapest day to fly to Region of Ontario from St. Louis. The lowest ticket price found for a Friday departure recently was $793. Keep in mind that prices can always vary depending on your route and whether or not you are flying domestic or international. Flights from St. Louis to Region of Ontario on a Saturday will generally be more expensive and average around $968. Keep in mind that these prices on both days could fluctuate depending on the season and the demand.

What is the cheapest time of day to depart on your flight to Region of Ontario?

According to our data, the cheapest time of day to fly to Region of Ontario is in the morning. momondo users have found flights departing from St. Louis to Region of Ontario in the morning for as low as $732. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. Flights at noon are often more expensive with an average ticket price of $1,065.

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

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

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

There are 4 cabin classes available to choose from on St. Louis to Region of Ontario 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 St. Louis to Region of Ontario flights?

You could potentially save up to 55% on your flight if you consider stops on a St. Louis to Region of Ontario flight.

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

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

Best Price Found	$275
Fastest flight time	1h 54m
Direct flights	Every day
Airports in Region of Ontario	125 airports

The best one-way flight to Region of Ontario from St. Louis in the past 72 hours is $275. The best round-trip flight deal from St. Louis to Region of Ontario found on momondo in the last 72 hours is $405.

The fastest flight from St. Louis to Region of Ontario takes 1h 54m

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

There are 125 airports in Region of Ontario. From St. Louis there are direct flights to Montreal Pierre Elliott Trudeau Intl (YUL), Toronto Pearson Intl (YYZ).

Search flight deals

Frequently asked questions about flying from St. Louis to Ontario

When did momondo last update prices for flights from Lambert-St Louis Airport to Ontario?
Prices for flights from Lambert-St Louis Airport to Ontario were last updated today.
How many operators does momondo search for flights from Lambert-St Louis Airport to Ontario?
The number of operators available for flights from Lambert-St Louis Airport to Ontario is 3 as of July 2026.
How old do you have to be to fly from Lambert-St Louis Airport to Ontario?
The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Lambert-St Louis Airport to Ontario.
What documentation or ID do you need to fly to Ontario?
The required travel and health documents for your Ontario trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Ontario. We recommend that you seek guidance from your airline or a reliable third party such as IATA.
What is the most popular plane model from St. Louis to Region of Ontario?
momondo data reveals that the most frequently booked plane model on the route from St. Louis to Region of Ontario is Canadair (Bombardier) Regional Jet 900, representing 42.93% of all bookings. The subsequent popular models are Airbus A220-300 at 29.35%, Embraer 175 at 7.61%, and Boeing 737 MAX 8 at 5.43%.

Best airlines flying from St. Louis to Region of Ontario

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

Airline	Rating	Free Cancellation	Price
Air Canada	PriceFrom $139	Free Cancellation	Rating 7.1 11,388 reviews	Search Air Canada flights
United Airlines	PriceFrom $203	Free Cancellation	Rating 7.4 10,041 reviews	Search United Airlines flights
American Airlines	PriceFrom $270	Free Cancellation	Rating 7.1 11,845 reviews	Search American Airlines flights

Why use momondo?

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

It is quick and easy to find St. Louis to Ontario 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 Ontario that suits you.

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

Yes. All flights to Ontario from St. Louis on momondo can be compared and filtered by various policies on offer, including flexible booking.

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

Once you have performed a search for St. Louis to Ontario 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 St. Louis to Ontario right now. Can momondo alert me if prices change?

If you are simply researching potential flights to Ontario, momondo offers a useful price alert feature which will track prices for flights to Ontario from St. Louis and alert you when they change.

An easier way to manage your Region of Ontario trip

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Popular cities in Ontario

Flights to Torontofrom $178

Flights to Vancouverfrom $130

Flights to Montrealfrom $166

Flights to Calgaryfrom $175

Flights to Ottawafrom $232

Flights to Halifaxfrom $266

Flights to Winnipegfrom $234

Flights to Québec Cityfrom $341

Flights to Saskatoonfrom $307

Flights to Kelownafrom $267

Flights to St. John'sfrom $398

Flights to Reginafrom $306

Cheap flights from St. Louis to Ontario from $144

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from St. Louis to Ontario departing on 9/16. 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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American Airlines flights from St. Louis to Region of Ontario

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

WestJet flights from St. Louis to Region of Ontario

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

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

What is the cheapest month to fly to Region of Ontario?

What is the cheapest day to depart on your flight to Region of Ontario?

What is the cheapest time of day to depart on your flight to Region of Ontario?

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

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

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

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

What airlines fly to Region of Ontario?

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

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

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

Best Price Found

Fastest flight time

Direct flights

Airports in Region of Ontario

Frequently asked questions about flying from St. Louis to Ontario

Best airlines flying from St. Louis to Region of Ontario

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

Why use momondo?

An easier way to manage your Region of Ontario 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 Ontario

Popular cities in Ontario

Popular flights according to clicks in the last 7 days on momondo

St. Louis flight routes

According to popular flight searches on momondo this year

Region of Ontario flight routes

According to popular flight searches on momondo this year

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