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Cheap flights from St. Louis to Ontario from $115

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 12/7. 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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0 bags

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Cheap round-trip flights

Enter your travel dates to find the best prices.
American Airlines Logo
6:04 am - 5:20 pmSTL-YYZ
10h 16m1 stop
American Airlines Logo
11:25 am - 9:44 pmYYZ-STL
11h 19m1 stop
$269American Airlines
Find Deal
Sat, Feb 14 - Sat, Feb 21
American Airlines Logo
8:38 am - 5:44 pmSTL-YYZ
8h 06m1 stop
American Airlines Logo
6:00 am - 7:06 pmYYZ-STL
14h 06m1 stop
$271American Airlines
Find Deal
Fri, Dec 5 - Sat, Dec 6
Multiple Airlines Logo
10:48 am - 9:19 pmSTL-YYZ
33h 31m2 stops
Multiple Airlines Logo
7:15 am - 10:33 pmYYZ-STL
16h 18m1 stop
$319Multiple Airlines
Find Deal
Tue, Dec 23 - Tue, Jan 6
Multiple Airlines Logo
2:57 pm - 2:40 pmSTL-YYZ
22h 43m1 stop
Multiple Airlines Logo
8:30 pm - 9:52 amYYZ-STL
14h 22m2 stops
$332Multiple Airlines
Find Deal
Thu, Dec 11 - Sun, Dec 14
Air Canada Logo
4:05 pm - 11:04 pmSTL-YOW
5h 59m1 stop
Air Canada Logo
9:15 am - 3:24 pmYOW-STL
7h 09m1 stop
$361Air Canada
Find Deal
Tue, Apr 7 - Wed, Apr 8
United Airlines Logo
6:42 pm - 10:26 amSTL-YOW
14h 44m1 stop
United Airlines Logo
7:30 pm - 12:15 pmYOW-STL
17h 45m2 stops
$372United Airlines
Find Deal
Sat, Dec 6 - Sat, Dec 13
Air Canada Logo
4:05 pm - 7:06 pmSTL-YYZ
2h 01mnonstop
Air Canada Logo
2:00 pm - 3:29 pmYYZ-STL
2h 29mnonstop
$400Air Canada
Find Deal
Thu, Dec 11 - Sun, Dec 14
United Airlines Logo
7:41 am - 11:59 pmSTL-YYZ
15h 18m1 stop
United Airlines Logo
3:30 pm - 10:59 pmYYZ-STL
8h 29m1 stop
$416United Airlines
Find Deal
Tue, Mar 3 - Wed, Mar 4
Delta Logo
6:00 am - 6:40 pmSTL-YUL
11h 40m1 stop
Delta Logo
7:45 pm - 8:20 amYUL-STL
13h 35m1 stop
$520Delta
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Mon, Nov 24 - Tue, Dec 2
Delta Logo
6:40 am - 6:40 pmSTL-YUL
11h 00m2 stops
Delta Logo
7:45 pm - 8:20 amYUL-STL
13h 35m1 stop
$563Delta
Find Deal
Mon, Nov 24 - Tue, Dec 2

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
Feb 14
STL6:04 amLambert-St Louis
10h 16m
1 stop
YYZ5:20 pmToronto Pearson Intl
Feb 21
YYZ11:25 amToronto Pearson Intl
11h 19m
1 stop
STL9:44 pmLambert-St Louis
$269
Find similar
American Airlines
Dec 5
STL8:38 amLambert-St Louis
8h 06m
1 stop
YYZ5:44 pmToronto Pearson Intl
Dec 6
YYZ6:00 amToronto Pearson Intl
14h 06m
1 stop
STL7:06 pmLambert-St Louis
$271
Find similar
American Airlines
Dec 12
STL8:38 amLambert-St Louis
8h 06m
1 stop
YYZ5:44 pmToronto Pearson Intl
Dec 14
YYZ6:00 amToronto Pearson Intl
9h 50m
1 stop
STL2:50 pmLambert-St Louis
$272
Find similar

WestJet flights from St. Louis to Region of Ontario

Our best WestJet deals on St. Louis to Region of Ontario flight tickets
WestJet
Nov 1
STL3:59 pmLambert-St Louis
27h 37m
2 stops
YYZ8:36 pmToronto Pearson Intl
Nov 4
YYZ6:45 pmToronto Pearson Intl
21h 44m
1 stop
STL3:29 pmLambert-St Louis
$894
Find similar
WestJet
Oct 24
STL6:00 amLambert-St Louis
23h 52m
2 stops
YYZ6:52 amToronto Pearson Intl
Oct 25
YYZ6:30 pmToronto Pearson Intl
22h 40m
2 stops
STL4:10 pmLambert-St Louis
$1,393
Find similar
WestJet
Oct 25
STL6:40 amLambert-St Louis
3h 40m
1 stop
YYZ11:20 amToronto Pearson Intl
Oct 27
YYZ9:45 amToronto Pearson Intl
4h 37m
1 stop
STL1:22 pmLambert-St Louis
$1,689
Find similar

momondo Fare Finder

 
Customize your flight search to find flights from St. Louis to Region of Ontario that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, momondo users made 832,500 searches. Data last updated October 23, 2025.
Use the filters below to find and compare flights from St. Louis to Ontario that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Sat 2/14

6:04 am-5:20 pm

1 stop10h 16m

Toronto Pearson Intl

Sat 2/21

11:25 am-9:44 pm

1 stop11h 19m

$269

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Fri 12/5

8:38 am-5:44 pm

1 stop8h 06m

Toronto Pearson Intl

Sat 12/6

6:00 am-7:06 pm

1 stop14h 06m

$271

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Tue 12/23

10:48 am-9:19 pm

2 stops33h 31m

Toronto Pearson Intl

Tue 1/6

7:15 am-10:33 pm

1 stop16h 18m

$319

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Thu 12/11

2:57 pm-2:40 pm

1 stop22h 43m

Toronto Pearson Intl

Sun 12/14

8:30 pm-9:52 am

2 stops14h 22m

$332

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Tue 4/7

4:05 pm-11:04 pm

1 stop5h 59m

Ottawa

Wed 4/8

9:15 am-3:24 pm

1 stop7h 09m

$361

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sat 12/6

6:42 pm-10:26 am

1 stop14h 44m

Ottawa

Sat 12/13

7:30 pm-12:15 pm

2 stops17h 45m

$372

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Thu 12/11

4:05 pm-7:06 pm

Nonstop2h 01m

Toronto Pearson Intl

Sun 12/14

2:00 pm-3:29 pm

Nonstop2h 29m

$400

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Tue 3/3

7:41 am-11:59 pm

1 stop15h 18m

Toronto Pearson Intl

Wed 3/4

3:30 pm-10:59 pm

1 stop8h 29m

$416

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Mon 11/24

6:00 am-6:40 pm

1 stop11h 40m

Montreal Pierre Elliott Trudeau Intl

Tue 12/2

7:45 pm-8:20 am

1 stop13h 35m

$520

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Mon 11/24

6:40 am-6:40 pm

2 stops11h 00m

Montreal Pierre Elliott Trudeau Intl

Tue 12/2

7:45 pm-8:20 am

1 stop13h 35m

$563

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to Ontario from

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

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

The month of January is, on average, the cheapest month to fly to Region of Ontario from St. Louis, with most prices found around $286. If you aren’t able to travel during the month of January, then book flights to Region of Ontario from St. Louis during April instead. Flights to Region of Ontario in April, while not as cheap as those in January, still average around $314.

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

According to our data, Tuesday is the cheapest day to fly to Region of Ontario from St. Louis. The lowest ticket price found for a Tuesday departure recently was $838. 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 Friday will generally be more expensive and average around $986. 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 afternoon. momondo users have found flights departing from St. Louis to Region of Ontario in the afternoon for as low as $898. 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 $1,180.

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

How far in advance should I book a flight to Region of Ontario?

You are more likely to see cheaper flights to Region of Ontario from St. Louis when booking weeks ahead of your departure date. In general, you can expect to find flights to Region of Ontario for around $488 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Region of Ontario from St. Louis for as low as $221 on momondo.

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

There are 4 cabin classes available to choose from on Lambert-St Louis to 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 33% 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

$141

Fastest flight time

2h 01m

Direct flights

Every day

Airports in Region of Ontario

1 airport
The best one-way flight to Region of Ontario from St. Louis in the past 72 hours is $141. The best round-trip flight deal from St. Louis to Region of Ontario found on momondo in the last 72 hours is $633.
The fastest flight from St. Louis to Region of Ontario takes 2h 01m
Direct flights go from St. Louis to Region of Ontario every day.
There is 1 airport near Region of Ontario: Toronto Pearson Intl (YYZ)
Search flight deals

  • 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?

  • 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?

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
United AirlinesPriceFrom $214Free CancellationRating
7.4
8,991 reviews
Search United Airlines flights
Air CanadaPriceFrom $220Free CancellationRating
7.1
10,346 reviews
Search Air Canada flights
American AirlinesPriceFrom $391Free CancellationRating
7.2
11,028 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

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.
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