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Cheap flights from St. Louis to Ontario from C$ 185

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 18/9. 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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Find the cheapest flights from St. Louis to Ontario

Cheap round-trip flights

Logo
10:35 a.m. - 8:55 p.m.STL-YYZ
9h 20m1 stop
Logo
6:30 a.m. - 9:40 a.m.YYZ-STL
28h 10m1 stop
C$ 452
Find Deal
Thu, 18 Sep - Sat, 20 Sep
Logo
10:35 a.m. - 8:55 p.m.STL-YYZ
9h 20m1 stop
Logo
6:30 a.m. - 9:40 a.m.YYZ-STL
28h 10m1 stop
C$ 455
Find Deal
Thu, 18 Sep - Sat, 20 Sep
Logo
10:35 a.m. - 11:52 p.m.STL-YYZ
12h 17m1 stop
Logo
1:30 p.m. - 10:02 a.m.YYZ-STL
21h 32m1 stop
C$ 461
Find Deal
Thu, 2 Oct - Mon, 6 Oct
American Airlines Logo
6:00 a.m. - 4:04 p.m.STL-YYZ
9h 04m1 stop
American Airlines Logo
11:32 a.m. - 7:27 p.m.YYZ-STL
8h 55m1 stop
C$ 474American Airlines
Find Deal
Tue, 18 Nov - Sat, 22 Nov
American Airlines Logo
6:00 a.m. - 5:40 p.m.STL-YYZ
10h 40m1 stop
American Airlines Logo
11:45 a.m. - 6:11 p.m.YYZ-STL
7h 26m1 stop
C$ 485American Airlines
Find Deal
Wed, 22 Oct - Sat, 1 Nov
United Airlines Logo
5:28 p.m. - 10:40 a.m.STL-YUL
16h 12m1 stop
United Airlines Logo
6:15 a.m. - 2:27 p.m.YUL-STL
9h 12m1 stop
C$ 536United Airlines
Find Deal
Tue, 14 Oct - Tue, 21 Oct
United Airlines Logo
5:28 p.m. - 10:40 a.m.STL-YUL
16h 12m1 stop
United Airlines Logo
6:15 a.m. - 3:44 p.m.YUL-STL
10h 29m1 stop
C$ 564United Airlines
Find Deal
Tue, 14 Oct - Thu, 23 Oct
Delta Logo
1:35 p.m. - 8:37 a.m.STL-YUL
18h 02m1 stop
Delta Logo
7:30 p.m. - 11:38 a.m.YUL-STL
17h 08m1 stop
C$ 709Delta
Find Deal
Sat, 11 Oct - Fri, 24 Oct
Air Canada Logo
4:05 p.m. - 9:27 p.m.STL-YXU
4h 22m1 stop
Air Canada Logo
9:55 a.m. - 3:18 p.m.YXU-STL
6h 23m1 stop
C$ 1,273Air Canada
Find Deal
Wed, 1 Oct - Wed, 8 Oct
Air Canada Logo
9:15 a.m. - 3:17 p.m.STL-YXU
5h 02m1 stop
Air Canada Logo
9:55 a.m. - 3:18 p.m.YXU-STL
6h 23m1 stop
C$ 1,332Air Canada
Find Deal
Mon, 29 Sep - Mon, 6 Oct

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
18 Nov
STL6:00 a.m.Lambert-St Louis
9h 04m
1 stop
YYZ4:04 p.m.Toronto Pearson Intl
22 Nov
YYZ11:32 a.m.Toronto Pearson Intl
8h 55m
1 stop
STL7:27 p.m.Lambert-St Louis
C$ 474
Find similar
American Airlines
22 Oct
STL6:00 a.m.Lambert-St Louis
10h 40m
1 stop
YYZ5:40 p.m.Toronto Pearson Intl
1 Nov
YYZ11:45 a.m.Toronto Pearson Intl
7h 26m
1 stop
STL6:11 p.m.Lambert-St Louis
C$ 485
Find similar
American Airlines
18 Oct
STL8:42 a.m.Lambert-St Louis
7h 58m
1 stop
YYZ5:40 p.m.Toronto Pearson Intl
21 Oct
YYZ11:44 a.m.Toronto Pearson Intl
9h 42m
1 stop
STL8:26 p.m.Lambert-St Louis
C$ 495
Find similar

United Airlines flights from St. Louis to Region of Ontario

Our best United Airlines deals on St. Louis to Region of Ontario flight tickets
United Airlines
14 Oct
STL5:28 p.m.Lambert-St Louis
16h 12m
1 stop
YUL10:40 a.m.Montreal Pierre Elliott Trudeau Intl
21 Oct
YUL6:15 a.m.Montreal Pierre Elliott Trudeau Intl
9h 12m
1 stop
STL2:27 p.m.Lambert-St Louis
C$ 536
Find similar
United Airlines
14 Oct
STL5:28 p.m.Lambert-St Louis
16h 12m
1 stop
YUL10:40 a.m.Montreal Pierre Elliott Trudeau Intl
23 Oct
YUL6:15 a.m.Montreal Pierre Elliott Trudeau Intl
10h 29m
1 stop
STL3:44 p.m.Lambert-St Louis
C$ 564
Find similar
United Airlines
27 Sep
STL9:20 a.m.Lambert-St Louis
24h 20m
1 stop
YUL10:40 a.m.Montreal Pierre Elliott Trudeau Intl
30 Sep
YUL8:00 p.m.Montreal Pierre Elliott Trudeau Intl
19h 27m
2 stops
STL2:27 p.m.Lambert-St Louis
C$ 578
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 96,600 searches. Data last updated 18 August 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

Thu 18/9

10:35 a.m.-8:55 p.m.

1 stop9h 20m

Toronto Pearson Intl

Sat 20/9

6:30 a.m.-9:40 a.m.

1 stop28h 10m

C$ 452

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Thu 18/9

10:35 a.m.-8:55 p.m.

1 stop9h 20m

Toronto Pearson Intl

Sat 20/9

6:30 a.m.-9:40 a.m.

1 stop28h 10m

C$ 455

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Thu 2/10

10:35 a.m.-11:52 p.m.

1 stop12h 17m

Toronto Pearson Intl

Mon 6/10

1:30 p.m.-10:02 a.m.

1 stop21h 32m

C$ 461

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Tue 18/11

6:00 a.m.-4:04 p.m.

1 stop9h 04m

Toronto Pearson Intl

Sat 22/11

11:32 a.m.-7:27 p.m.

1 stop8h 55m

C$ 474

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Wed 22/10

6:00 a.m.-5:40 p.m.

1 stop10h 40m

Toronto Pearson Intl

Sat 1/11

11:45 a.m.-6:11 p.m.

1 stop7h 26m

C$ 485

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Tue 14/10

5:28 p.m.-10:40 a.m.

1 stop16h 12m

Montreal Pierre Elliott Trudeau Intl

Tue 21/10

6:15 a.m.-2:27 p.m.

1 stop9h 12m

C$ 536

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Tue 14/10

5:28 p.m.-10:40 a.m.

1 stop16h 12m

Montreal Pierre Elliott Trudeau Intl

Thu 23/10

6:15 a.m.-3:44 p.m.

1 stop10h 29m

C$ 564

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Sat 11/10

1:35 p.m.-8:37 a.m.

1 stop18h 02m

Montreal Pierre Elliott Trudeau Intl

Fri 24/10

7:30 p.m.-11:38 a.m.

1 stop17h 08m

C$ 709

St. LouisLondon

STL - YXU

STLYXU

Lambert-St Louis

Wed 1/10

4:05 p.m.-9:27 p.m.

1 stop4h 22m

London

Wed 8/10

9:55 a.m.-3:18 p.m.

1 stop6h 23m

C$ 1,273

St. LouisLondon

STL - YXU

STLYXU

Lambert-St Louis

Mon 29/9

9:15 a.m.-3:17 p.m.

1 stop5h 02m

London

Mon 6/10

9:55 a.m.-3:18 p.m.

1 stop6h 23m

C$ 1,332

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?

In general, November is the cheapest month to fly from St. Louis to Region of Ontario. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around C$ 369. If you are unable to visit Region of Ontario during the month of November, then departing from St. Louis during the month January is also very affordable. Most momondo users find prices during this month for around C$ 395.

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

The cheapest day to depart from St. Louis to Region of Ontario is on a Thursday. Travellers who choose to depart for Region of Ontario on a Thursday will often find tickets for as low as C$ 356. The most expensive day to fly to Region of Ontario is Sunday, with ticket prices averaging around C$ 927.

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

Our most recent data shows that the best time of day to fly to Region of Ontario is at noon. Flights from St. Louis to Region of Ontario during this time can be as low as C$ 592. If you have a flexible travel schedule, then try to avoid flying in the morning when prices are C$ 781 on average. Flights to Region of Ontario from St. Louis in the morning are generally more expensive because this time of day is more convenient for travellers’ schedules.

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 C$ 632 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 C$ 305 on momondo.

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

There are 1 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 67% 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

C$ 185

Fastest flight time

1h 55m

Direct flights

Every day

Airports in Region of Ontario

3 airports
The best one-way flight to Region of Ontario from St. Louis in the past 72 hours is C$ 185. The best round-trip flight deal from St. Louis to Region of Ontario found on momondo in the last 72 hours is C$ 452.
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 3 airports near Region of Ontario: Montreal Pierre Elliott Trudeau Intl (YUL), London (YXU), 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 are refreshed on a daily basis.

  • 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 that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check 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
Air CanadaPriceFrom C$ 301Free CancellationRating
7.1
9,992 reviews
Search Air Canada flights

Why use momondo?

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

We help find the flight that best suits your needs, momondo compares prices from hundreds of airlines and travel agents and helps you filter them to find the best flight from St. Louis to Ontario for you.

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

Yes. momondo allows you to filter the results for St. Louis to Ontario flights to just show those with flexible booking policies.

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

momondo helps you find the best flight between St. Louis and Ontario by providing filters to narrow your choice of flights to those matching your criteria. You can select flights based on numerous factors such as price, departure and landing times, airport and airline.

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 not ready to book a flight from St. Louis to Ontario now, use our insights above to find helpful tips or alternatively set up a price alert, where momondo will track prices on flights to Ontario and let you know when they change.

An easier way to manage your Region of Ontario trip

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Find better results for your trip to Ontario

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