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Cheap flights from St. Louis to Ontario from $73

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 1/21. 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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Find the cheapest flights from St. Louis to Ontario

Cheap round-trip flights

Enter your travel dates to find the best prices.
Multiple Airlines Logo
9:54 am - 2:20 pm
STL
-
YYZ
27h 26m1 stop
Multiple Airlines Logo
7:10 am - 10:33 pm
YYZ
-
STL
16h 23m1 stop
$229Multiple Airlines
Sun, Dec 14 - Tue, Dec 16
Multiple Airlines Logo
5:42 pm - 2:16 pm
STL
-
YYZ
19h 34m1 stop
Multiple Airlines Logo
7:10 am - 11:33 pm
YYZ
-
STL
17h 23m1 stop
$254Multiple Airlines
Tue, Jan 27 - Thu, Jan 29
American Airlines Logo
10:04 am - 9:29 pm
STL
-
YYZ
10h 25m1 stop
American Airlines Logo
6:00 am - 1:56 pm
YYZ
-
STL
8h 56m1 stop
$269American Airlines
Sat, Feb 14 - Sat, Feb 21
American Airlines Logo
6:35 pm - 10:56 am
STL
-
YYZ
15h 21m1 stop
American Airlines Logo
6:00 am - 2:45 pm
YYZ
-
STL
9h 45m1 stop
$270American Airlines
Sat, Feb 14 - Sat, Feb 21
Multiple Airlines Logo
8:50 am - 12:25 am
STL
-
YYZ
14h 35m1 stop
Multiple Airlines Logo
3:40 pm - 6:51 am
YYZ
-
STL
40h 11m2 stops
$271Multiple Airlines
Mon, Jan 12 - Mon, Jan 19
American Airlines Logo
6:00 am - 3:05 pm
STL
-
YUL
8h 05m1 stop
American Airlines Logo
3:55 pm - 9:34 am
YUL
-
STL
18h 39m1 stop
$273American Airlines
Tue, Feb 17 - Fri, Feb 20
Air Canada Logo
4:05 pm - 11:08 pm
STL
-
YOW
6h 03m1 stop
Air Canada Logo
9:15 am - 3:29 pm
YOW
-
STL
7h 14m1 stop
$308Air Canada
Tue, Feb 24 - Thu, Mar 5
Air Canada Logo
4:05 pm - 11:08 pm
STL
-
YOW
6h 03m1 stop
Air Canada Logo
10:20 am - 3:29 pm
YOW
-
STL
6h 09m1 stop
$338Air Canada
Tue, Mar 3 - Fri, Mar 20
United Airlines Logo
6:30 am - 2:27 pm
STL
-
YOW
6h 57m2 stops
United Airlines Logo
5:55 pm - 11:51 pm
YOW
-
STL
6h 56m1 stop
$362United Airlines
Tue, Feb 24 - Thu, Mar 5
United Airlines Logo
8:05 am - 5:12 pm
STL
-
YOW
8h 07m1 stop
United Airlines Logo
2:15 pm - 9:13 pm
YOW
-
STL
7h 58m2 stops
$372United Airlines
Sun, Jan 18 - Wed, Jan 21

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
STL10:04 amLambert-St Louis
10h 25m
1 stop
YYZ9:29 pmToronto Pearson Intl
Feb 21
YYZ6:00 amToronto Pearson Intl
8h 56m
1 stop
STL1:56 pmLambert-St Louis
$269
Find similar
American Airlines
Feb 14
STL6:35 pmLambert-St Louis
15h 21m
1 stop
YYZ10:56 amToronto Pearson Intl
Feb 21
YYZ6:00 amToronto Pearson Intl
9h 45m
1 stop
STL2:45 pmLambert-St Louis
$270
Find similar
American Airlines
Feb 17
STL6:00 amLambert-St Louis
8h 05m
1 stop
YUL3:05 pmMontreal Pierre Elliott Trudeau Intl
Feb 20
YUL3:55 pmMontreal Pierre Elliott Trudeau Intl
18h 39m
1 stop
STL9:34 amLambert-St Louis
$273
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
Mar 6
STL6:10 amLambert-St Louis
25h 24m
2 stops
YYZ8:34 amToronto Pearson Intl
Mar 8
YYZ6:20 amToronto Pearson Intl
15h 21m
1 stop
STL8:41 pmLambert-St Louis
$530
Find similar
WestJet
Dec 5
STL11:40 amLambert-St Louis
18h 25m
2 stops
YUL7:05 amMontreal Pierre Elliott Trudeau Intl
Dec 8
YUL7:30 pmMontreal Pierre Elliott Trudeau Intl
16h 15m
2 stops
STL10:45 amLambert-St Louis
$1,232
Find similar
WestJet
Dec 5
STL11:40 amLambert-St Louis
18h 25m
2 stops
YUL7:05 amMontreal Pierre Elliott Trudeau Intl
Dec 8
YUL7:30 pmMontreal Pierre Elliott Trudeau Intl
18h 34m
2 stops
STL1:04 pmLambert-St Louis
$1,313
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 December 4, 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

Sun 12/14

9:54 am-2:20 pm

1 stop27h 26m

Toronto Pearson Intl

Tue 12/16

7:10 am-10:33 pm

1 stop16h 23m

$229

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Tue 1/27

5:42 pm-2:16 pm

1 stop19h 34m

Toronto Pearson Intl

Thu 1/29

7:10 am-11:33 pm

1 stop17h 23m

$254

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Sat 2/14

10:04 am-9:29 pm

1 stop10h 25m

Toronto Pearson Intl

Sat 2/21

6:00 am-1:56 pm

1 stop8h 56m

$269

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Sat 2/14

6:35 pm-10:56 am

1 stop15h 21m

Toronto Pearson Intl

Sat 2/21

6:00 am-2:45 pm

1 stop9h 45m

$270

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Mon 1/12

8:50 am-12:25 am

1 stop14h 35m

Toronto Pearson Intl

Mon 1/19

3:40 pm-6:51 am

2 stops40h 11m

$271

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Tue 2/17

6:00 am-3:05 pm

1 stop8h 05m

Montreal Pierre Elliott Trudeau Intl

Fri 2/20

3:55 pm-9:34 am

1 stop18h 39m

$273

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Tue 2/24

4:05 pm-11:08 pm

1 stop6h 03m

Ottawa

Thu 3/5

9:15 am-3:29 pm

1 stop7h 14m

$308

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Tue 3/3

4:05 pm-11:08 pm

1 stop6h 03m

Ottawa

Fri 3/20

10:20 am-3:29 pm

1 stop6h 09m

$338

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Tue 2/24

6:30 am-2:27 pm

2 stops6h 57m

Ottawa

Thu 3/5

5:55 pm-11:51 pm

1 stop6h 56m

$362

St. LouisOttawa

STL - YOW

STLYOW

Lambert-St Louis

Sun 1/18

8:05 am-5:12 pm

1 stop8h 07m

Ottawa

Wed 1/21

2:15 pm-9:13 pm

2 stops7h 58m

$372

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 $287. 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 $813. 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 $994. 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 $888. 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 2% 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

$399

Fastest flight time

1h 55m

Direct flights

Every day

Airports in Region of Ontario

2 airports
The best one-way flight to Region of Ontario from St. Louis in the past 72 hours is $399. The best round-trip flight deal from St. Louis to Region of Ontario found on momondo in the last 72 hours is $578.
The fastest flight from St. Louis to Region of Ontario takes 1h 55m
Direct flights go from St. Louis to Region of Ontario every day.
There are 2 airports near Region of Ontario: Montreal Pierre Elliott Trudeau Intl (YUL), 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 $199Free CancellationRating
7.4
9,063 reviews
Search United Airlines flights
Air CanadaPriceFrom $220Free CancellationRating
7.1
10,500 reviews
Search Air Canada flights
American AirlinesPriceFrom $270Free CancellationRating
7.2
11,045 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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