What are the cheapest airlines to fly from St. Louis to Region of Ontario one-way?

For one-way options, check prices for Delta. According to our data, you can fly for as low as C$ 293. Users have also found prices from C$ 335 and C$ 338 on United Airlines and Air Canada, respectively.

What are the most popular routes from St. Louis to Region of Ontario?

The most popular flight routes from St. Louis to Region of Ontario are Lambert-St Louis - Toronto Pearson Intl, Lambert-St Louis - Montreal Pierre Elliott Trudeau Intl and Lambert-St Louis - London.

What are the cheapest flights from St. Louis to Region of Ontario?

The cheapest flight price from St. Louis to Region of Ontario is C$ 309. On average you can expect to pay C$ 809. The most popular route, (Lambert-St Louis - Toronto Pearson Intl), can usually be booked for C$ 469.

What are the most reliable airlines from St. Louis to Region of Ontario?

Before booking your flight to Region of Ontario from St. Louis, check out the most reliable airlines to get you to your destination on time: Air Canada (78%), Jazz (78%), United Airlines( 78%).

How far in advance should I book a flight from St. Louis to Region of Ontario?

When searching for a good deal, it’s best to be prepared for potential fluctuations in price. We recommend booking at least 53 days in advance, which can save you up to 399% on flights from St. Louis to Region of Ontario compared to booking the week you need them. Waiting 53 days out may not be for everyone, so we have options available for flights within the next two weeks, with the lowest price starting at C$ 435. For sooner than that we have options available in the next 3 days from C$ 1,258.

What is the cheapest month to fly from St. Louis to Region of Ontario?

May is one of the best times of the year to fly to Region of Ontario from St. Louis. Prices for May average C$ 555 per person but you can even find prices for as low as C$ 310. The most expensive prices can be found in the month of March. Opting for a May flight can save you 45% on your journey compared to booking in March

What airport do you fly from for flights from St. Louis to Ontario?

If you book a flight to Ontario from St. Louis, you will be flying from Lambert-St Louis, which is the city’s only airport. Lambert-St Louis (STL) is located 20.4 km from the centre of St. Louis.

Can I find deals for flights from St. Louis to Ontario that include hotel bookings?

Yes. In addition to deals on St. Louis to Ontario flights, Cheapflights offers vacation packages that include both flights and hotel.

How can I find direct flights from St. Louis to Ontario?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from St. Louis to Ontario.

Can I find deals for business class flights from St. Louis to Ontario?

Yes. Cheapflights offers flight deals from St. Louis to Ontario by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

C$ 227+ Flights from St. Louis to Ontario

Cheap flight deals from St. Louis to Ontario

Round-trip from	C$ 469
One-way from	C$ 227
Popular in	March
Cheapest in	May
Average price	C$ 435
Good one-way deal	C$ 461 or less

20/6-22/6
2 total stops
54h 40m total
St. Louis to Ontario

Search Deals

13/5
1 total stop
27h 59m total
St. Louis to Ontario

Search Deals

Highest demand for flights based on searches. 3% potential increase in price (C$ 26 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 4% potential price decrease (C$ 33 potential savings vs. average RT price).

Search Deals

Average for round-trip flights in April 2025

Search Deals

Price to beat on a one-way flight from Lambert-St Louis to Ontario.

Search Deals

Find flight deals from St. Louis to Ontario

Cheapest flights from St. Louis to Ontario
Explore the most affordable flight options available from St. Louis to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 30 April 2025.

Fri 20/611:28 a.m.STL - YYZ

1 stop25h 37mMultiple Airlines

Sun 22/66:30 a.m.YYZ - STL

1 stop29h 03mMultiple Airlines

Deal found 28/4C$ 469

Tue 27/56:00 a.m.STL - YYZ

1 stop13h 44mDelta

Wed 9/76:15 a.m.YYZ - STL

1 stop15h 42mDelta

Deal found 27/4C$ 597

Thu 29/56:45 p.m.STL - YUL

1 stop25h 24mDelta

Mon 2/66:05 a.m.YUL - STL

1 stop15h 43mDelta

Deal found 28/4C$ 626

Thu 12/66:12 p.m.STL - YUL

3 stops29h 25mMultiple Airlines

Sun 15/66:45 a.m.YUL - STL

2 stops28h 48mMultiple Airlines

Deal found 27/4C$ 656

Fri 13/67:30 a.m.STL - YYZ

Nonstop1h 55mAir Canada

Fri 20/611:30 a.m.YYZ - STL

Nonstop2h 06mAir Canada

Deal found 29/4C$ 657

Sat 5/79:15 a.m.STL - YYZ

Nonstop1h 58mUnited Airlines

Fri 25/72:10 p.m.YYZ - STL

Nonstop2h 06mUnited Airlines

Deal found 28/4C$ 688

Thu 29/55:00 a.m.STL - YUL

1 stop4h 40mAir Canada

Mon 2/66:10 p.m.YUL - STL

Nonstop2h 48mAir Canada

Deal found 28/4C$ 700

Thu 10/75:15 a.m.STL - YYZ

1 stop8h 44mAmerican Airlines

Sun 20/76:00 a.m.YYZ - STL

1 stop6h 58mAmerican Airlines

Deal found 28/4C$ 743

Tue 13/56:00 p.m.STL - YUL

1 stop14h 50mAmerican Airlines

Tue 20/510:44 a.m.YUL - STL

1 stop9h 31mAmerican Airlines

Deal found 28/4C$ 764

Wed 11/611:48 a.m.STL - YYZ

2 stops11h 36mWestJet

Sun 15/63:31 p.m.YYZ - STL

1 stop6h 09mWestJet

Deal found 28/4C$ 817

Fri 15/88:15 a.m.STL - YUL

1 stop26h 25mUnited Airlines

Mon 18/84:40 p.m.YUL - STL

2 stops18h 22mUnited Airlines

Deal found 28/4C$ 878

Mon 13/105:45 p.m.STL - YUL

1 stop4h 23mWestJet

Sun 19/106:00 a.m.YUL - STL

1 stop4h 35mWestJet

Deal found 28/4C$ 998

Best flights from St. Louis to Ontario
Discover carefully curated flight deals from St. Louis to Ontario that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated 30 April 2025.

Fri 20/611:28 a.m.STL - YYZ

1 stop25h 37mMultiple Airlines

Sun 22/66:30 a.m.YYZ - STL

1 stop29h 03mMultiple Airlines

Deal found 28/4C$ 469

Tue 27/56:45 p.m.STL - YYZ

1 stop13h 45mDelta

Tue 8/77:55 a.m.YYZ - STL

1 stop14h 02mDelta

Deal found 27/4C$ 597

Fri 13/67:30 a.m.STL - YYZ

Nonstop1h 55mAir Canada

Fri 20/611:30 a.m.YYZ - STL

Nonstop2h 06mAir Canada

Deal found 29/4C$ 657

Sat 5/79:15 a.m.STL - YYZ

Nonstop1h 58mUnited Airlines

Fri 25/72:10 p.m.YYZ - STL

Nonstop2h 06mUnited Airlines

Deal found 28/4C$ 688

Thu 10/75:15 a.m.STL - YYZ

1 stop8h 44mAmerican Airlines

Sun 20/76:00 a.m.YYZ - STL

1 stop6h 58mAmerican Airlines

Deal found 28/4C$ 743

Wed 11/611:48 a.m.STL - YYZ

2 stops11h 36mWestJet

Sun 15/63:31 p.m.YYZ - STL

1 stop6h 09mWestJet

Deal found 28/4C$ 817

Thu 12/66:12 p.m.STL - YUL

3 stops29h 25mMultiple Airlines

Sun 15/66:55 a.m.YUL - STL

3 stops28h 38mMultiple Airlines

Deal found 29/4C$ 627

Thu 29/56:45 p.m.STL - YUL

1 stop25h 24mDelta

Mon 2/66:05 a.m.YUL - STL

1 stop15h 43mDelta

Deal found 29/4C$ 682

Sun 1/66:00 p.m.STL - YUL

1 stop14h 50mAmerican Airlines

Thu 5/610:35 a.m.YUL - STL

1 stop11h 20mAmerican Airlines

Deal found 30/4C$ 775

Thu 29/51:30 p.m.STL - YUL

Nonstop2h 30mAir Canada

Mon 2/66:10 p.m.YUL - STL

Nonstop2h 48mAir Canada

Deal found 29/4C$ 843

Thu 29/55:00 a.m.STL - YUL

1 stop4h 40mUnited Airlines

Thu 5/66:10 p.m.YUL - STL

Nonstop2h 48mUnited Airlines

Deal found 29/4C$ 880

Fri 13/66:00 a.m.STL - YUL

1 stop27h 08mWestJet

Fri 20/66:45 p.m.YUL - STL

1 stop22h 40mWestJet

Deal found 29/4C$ 1,005

Direct flights from St. Louis to Ontario
Explore direct flight options from St. Louis to Ontario based on user searches, and compare prices and availability for your desired travel dates. Data last updated 30 April 2025.

Fri 13/67:30 a.m.STL - YYZ

Nonstop1h 55mAir Canada

Fri 20/611:30 a.m.YYZ - STL

Nonstop2h 06mAir Canada

Deal found 29/4C$ 641

Sat 5/79:15 a.m.STL - YYZ

Nonstop1h 58mUnited Airlines

Fri 25/72:10 p.m.YYZ - STL

Nonstop2h 06mUnited Airlines

Deal found 28/4C$ 688

Thu 25/94:05 p.m.STL - YYZ

Nonstop1h 55mMultiple Airlines

Sun 28/96:30 p.m.YYZ - STL

Nonstop2h 03mMultiple Airlines

Deal found 28/4C$ 709

Thu 29/51:30 p.m.STL - YUL

Nonstop2h 30mAir Canada

Mon 2/66:10 p.m.YUL - STL

Nonstop2h 48mAir Canada

Deal found 29/4C$ 843

Thu 29/51:30 p.m.STL - YUL

Nonstop2h 30mUnited Airlines

Thu 5/66:10 p.m.YUL - STL

Nonstop2h 48mUnited Airlines

Deal found 30/4C$ 897

Wed 11/61:30 p.m.STL - YUL

Nonstop2h 30mMultiple Airlines

Mon 16/66:10 p.m.YUL - STL

Nonstop2h 48mMultiple Airlines

Deal found 29/4C$ 2,318

Last-minute flights from St. Louis to Ontario
Discover last-minute flight deals from St. Louis to Ontario. Data last updated 30 April 2025 and is based on user searches.

Mon 5/56:00 p.m.STL - YUL

1 stop14h 50mAmerican Airlines

Wed 7/510:44 a.m.YUL - STL

1 stop9h 31mAmerican Airlines

Deal found 28/4C$ 1,019

Mon 5/57:31 a.m.STL - YYZ

1 stop10h 04mAmerican Airlines

Fri 9/57:25 a.m.YYZ - STL

1 stop8h 30mAmerican Airlines

Deal found 28/4C$ 1,031

Mon 5/59:40 a.m.STL - YUL

2 stops11h 10mUnited Airlines

Wed 7/54:40 p.m.YUL - STL

2 stops24h 07mUnited Airlines

Deal found 28/4C$ 1,143

Mon 5/512:55 p.m.STL - YYZ

1 stop8h 56mDelta

Fri 9/52:30 p.m.YYZ - STL

2 stops7h 19mDelta

Deal found 28/4C$ 1,264

Mon 5/51:10 p.m.STL - YYZ

1 stop6h 34mUnited Airlines

Fri 9/56:30 p.m.YYZ - STL

Nonstop2h 13mUnited Airlines

Deal found 28/4C$ 1,459

Tue 6/55:45 p.m.STL - YYZ

1 stop29h 02mMultiple Airlines

Thu 8/59:50 a.m.YYZ - STL

1 stop15h 16mMultiple Airlines

Deal found 29/4C$ 687

Tue 6/55:32 p.m.STL - YYZ

2 stops24h 24mWestJet

Thu 8/56:15 a.m.YYZ - STL

1 stop6h 33mWestJet

Deal found 29/4C$ 875

Fri 9/55:55 p.m.STL - YUL

1 stop19h 25mMultiple Airlines

Sun 11/56:45 a.m.YUL - STL

2 stops18h 21mMultiple Airlines

Deal found 29/4C$ 775

Fri 9/52:30 p.m.STL - YYZ

Nonstop2h 00mAir Canada

Sun 11/56:30 p.m.YYZ - STL

Nonstop2h 13mAir Canada

Deal found 29/4C$ 1,229

Tue 13/56:00 p.m.STL - YUL

1 stop14h 50mAmerican Airlines

Tue 20/510:44 a.m.YUL - STL

1 stop9h 31mAmerican Airlines

Deal found 28/4C$ 764

Sat 24/510:10 a.m.STL - YYZ

1 stop11h 15mMultiple Airlines

Wed 28/54:00 p.m.YYZ - STL

1 stop8h 44mMultiple Airlines

Deal found 28/4C$ 501

Sun 25/512:03 p.m.STL - YYZ

1 stop8h 27mAmerican Airlines

Sat 31/57:25 a.m.YYZ - STL

1 stop8h 54mAmerican Airlines

Deal found 29/4C$ 760

One-way flights from St. Louis to Ontario
Search for one-way flight options from St. Louis to Ontario. Find affordable one-way fares based on user searches. Data last updated 30 April 2025.

Tue 13/55:45 p.m.STL - YYZ

1 stop27h 59mMultiple Airlines

Deal found 29/4C$ 227

Tue 10/66:00 a.m.STL - YYZ

1 stop13h 44mDelta

Deal found 29/4C$ 293

Thu 4/97:37 p.m.STL - YUL

1 stop18h 13mMultiple Airlines

Deal found 29/4C$ 314

Sun 24/84:00 p.m.STL - YYZ

Nonstop2h 00mUnited Airlines

Deal found 29/4C$ 335

Fri 20/67:30 a.m.STL - YYZ

Nonstop1h 55mAir Canada

Deal found 28/4C$ 338

Sat 13/99:00 a.m.STL - YUL

2 stops11h 26mDelta

Deal found 29/4C$ 353

Thu 22/55:12 a.m.STL - YYZ

2 stops12h 23mAmerican Airlines

Deal found 29/4C$ 407

Sat 13/96:00 a.m.STL - YUL

1 stop9h 40mAmerican Airlines

Deal found 29/4C$ 410

Thu 4/91:30 p.m.STL - YUL

Nonstop2h 30mAir Canada

Deal found 29/4C$ 494

Fri 13/67:30 a.m.STL - YXU

1 stop6h 28mUnited Airlines

Deal found 29/4C$ 537

Wed 14/51:09 p.m.STL - YYZ

3 stops15h 42mWestJet

Deal found 29/4C$ 918

Tue 6/51:30 p.m.STL - YUL

Nonstop2h 30mUnited Airlines

Deal found 29/4C$ 950

Cheapflights Fare Finder

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

Fri 20/6

11:28 a.m.-2:05 p.m.

1 stop25h 37m

Toronto Pearson Intl

Sun 22/6

6:30 a.m.-10:33 a.m.

1 stop29h 03m

C$ 469

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Tue 27/5

6:45 p.m.-9:30 a.m.

1 stop13h 45m

Toronto Pearson Intl

Tue 8/7

7:55 a.m.-8:57 p.m.

1 stop14h 02m

C$ 597

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Thu 12/6

6:12 p.m.-12:37 a.m.

3 stops29h 25m

Montreal Pierre Elliott Trudeau Intl

Sun 15/6

6:55 a.m.-10:33 a.m.

3 stops28h 38m

C$ 627

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Fri 13/6

7:30 a.m.-10:25 a.m.

Nonstop1h 55m

Toronto Pearson Intl

Fri 20/6

11:30 a.m.-12:36 p.m.

Nonstop2h 06m

C$ 657

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Thu 29/5

6:45 p.m.-9:09 p.m.

1 stop25h 24m

Montreal Pierre Elliott Trudeau Intl

Mon 2/6

6:05 a.m.-8:48 p.m.

1 stop15h 43m

C$ 682

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Sat 5/7

9:09 a.m.-4:44 p.m.

1 stop6h 35m

Toronto Pearson Intl

Fri 25/7

2:10 p.m.-3:16 p.m.

Nonstop2h 06m

C$ 688

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Thu 10/7

5:15 a.m.-2:59 p.m.

1 stop8h 44m

Toronto Pearson Intl

Sun 20/7

6:00 a.m.-11:58 a.m.

1 stop6h 58m

C$ 743

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Sun 1/6

6:00 p.m.-9:50 a.m.

1 stop14h 50m

Montreal Pierre Elliott Trudeau Intl

Thu 5/6

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

1 stop11h 20m

C$ 775

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Wed 11/6

11:48 a.m.-12:24 a.m.

2 stops11h 36m

Toronto Pearson Intl

Sun 15/6

3:31 p.m.-8:40 p.m.

1 stop6h 09m

C$ 817

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Thu 29/5

1:30 p.m.-5:00 p.m.

Nonstop2h 30m

Montreal Pierre Elliott Trudeau Intl

Mon 2/6

6:10 p.m.-7:58 p.m.

Nonstop2h 48m

C$ 843

Flights are sorted by cheapest round-trip flights first.

Deals found on 29/4

Showing 1-10 of 24 results

Best time to book a flight from St. Louis to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from St. Louis with our price prediction graph.

Estimated round-trip price

Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from St. Louis to Ontario

What is the cheapest month to book a flight from St. Louis to Region of Ontario?

Currently, January is the cheapest month in which you can book a flight from St. Louis to Region of Ontario (average of C$ 167). Flying from St. Louis to Region of Ontario in July is currently the most expensive (average of C$ 258). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from STL to ON?

When flying from St. Louis to Region of Ontario, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

Rainfall in Ontario by month

In terms of precipitation, rainfall in Region of Ontario ranges from 51.0 - 83.0 mm per month. June is typically the wettest month, when rainfall can reach 83.0 mm. February is typically the driest time to visit Region of Ontario when rainfall is around 51.0 mm.

Temperature in Ontario by month

If weather is an important factor for your trip to Region of Ontario, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 21.0 C. Travellers hoping to avoid the cold should look outside of January, when temperatures are typically at their lowest (around -6.0 C).

Reviews of airlines servicing Ontario

Read through reviews of airlines operating flights from St. Louis to Ontario, such as Delta, United Airlines and American Airlines. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.

Delta

8.0

Very good

7,936 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.

Delta

8.0

Very good

7,936 reviews

Delta

8.0

Very good

7,936 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.

United Airlines

7.4

Good

8,696 reviews

Delta

8.0

Very good

7,936 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.

American Airlines

7.2

Good

10,000 reviews

Delta

8.0

Very good

7,936 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.

WestJet

7.2

Good

2,823 reviews

Delta

8.0

Very good

7,936 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.

Air Canada

7.0

Good

9,242 reviews

Delta

8.0

Very good

7,936 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.

Related info for your journey

What airport do you fly from for flights from St. Louis to Ontario?
If you book a flight to Ontario from St. Louis, you will be flying from Lambert-St Louis, which is the city’s only airport. Lambert-St Louis (STL) is located 20.4 km from the centre of St. Louis.
What are the cheapest airlines to fly from St. Louis to Region of Ontario one-way?
For one-way options, check prices for Delta. According to our data, you can fly for as low as C$ 293. Users have also found prices from C$ 335 and C$ 338 on United Airlines and Air Canada, respectively.
What are the most popular routes from St. Louis to Region of Ontario?
The most popular flight routes from St. Louis to Region of Ontario are Lambert-St Louis - Toronto Pearson Intl, Lambert-St Louis - Montreal Pierre Elliott Trudeau Intl and Lambert-St Louis - London.
What are the most reliable airlines from St. Louis to Region of Ontario?
Before booking your flight to Region of Ontario from St. Louis, check out the most reliable airlines to get you to your destination on time: Air Canada (78%), Jazz (78%), United Airlines( 78%).
What are the cheapest flights from St. Louis to Region of Ontario?
The cheapest flight price from St. Louis to Region of Ontario is C$ 309. On average you can expect to pay C$ 809. The most popular route, (Lambert-St Louis - Toronto Pearson Intl), can usually be booked for C$ 469.
Can I find deals for flights from St. Louis to Ontario that include hotel bookings?
Yes. In addition to deals on St. Louis to Ontario flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from St. Louis to Ontario?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from St. Louis to Ontario.
Can I find deals for business class flights from St. Louis to Ontario?
Yes. Cheapflights offers flight deals from St. Louis to Ontario by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.
What is the cheapest month to book a flight from St. Louis to Region of Ontario?
Currently, January is the cheapest month in which you can book a flight from St. Louis to Region of Ontario (average of C$ 167). Flying from St. Louis to Region of Ontario in July is currently the most expensive (average of C$ 258). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

Alternative routes for St. Louis to Ontario

Complete your trip

Region of Ontario car rentals

Toronto Pearson Intl Airport car rentals

Ottawa Airport car rentals

Toronto Island Airport car rentals

Hamilton Airport car rentals

Toronto Region of Waterloo Intl Airport car rentals

London Airport car rentals

Thunder Bay Airport car rentals

Sault Ste Marie Airport car rentals

Timmins Airport car rentals

Kingston Airport car rentals

North Bay Airport car rentals

Direct flights to Canada

Top airline flying from St. Louis to Ontario

Airline	Cheapest	Average	Flexibility	On-time
Air Canada	CheapestC$ 302	AverageC$ 752	FlexibilityNo cancel fee	On-time67%	Search Air Canada flights

Fly with Cheapflights

How does Cheapflights help users find flights from St. Louis to Ontario?

Cheapflights helps you search for flights from St. Louis to Ontario via 900+ travel sites so you don’t have to. After performing a flight search, users can also filter their flight selection by filtering for price, number of stops, airlines, and so on.

Why should you use Cheapflights to find cheap flight tickets from St. Louis to Ontario?

By finding flights from multiple airlines and providers at completely no cost, Cheapflights helps millions of users like you annually find the best flights to Ontario from St. Louis.

Can Cheapflights find flights from St. Louis to Ontario with no change fees?

Certainly. Search results for flights to Ontario from St. Louis shown to you on Cheapflights can be narrowed down with different useful search filters, which includes flexible booking options.

Can Cheapflights notify me if prices for flights from St. Louis to Ontario become cheaper?

Yes! Start tracking prices for St. Louis to Ontario flights today and get alerted whenever prices for these flights change. To access this feature, click the bell icon next to the flight deals above, which will prompt you for a valid email address to receive your alerts.

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Cheap flights from St. Louis to Ontario from C$ 227

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 13/5. Fares are subject to change and may not be available on all flights or dates of travel.

Cheap flight deals from St. Louis to Ontario

Keep the following information in mind while searching for St. Louis to Ontario flight deals. Data was last updated 30 April 2025.

Round-trip from

One-way from

Popular in

Cheapest in

Average price

Good one-way deal

Find flight deals from St. Louis to Ontario

Cheapest flights from St. Louis to OntarioExplore the most affordable flight options available from St. Louis to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 30 April 2025.

Explore the most affordable flight options available from St. Louis to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 30 April 2025.

Cheapflights Fare Finder

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

Best time to book a flight from St. Louis to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from St. Louis with our price prediction graph.

Cheapflights Insights

Everything you need to know about your flight from St. Louis to Ontario

What is the cheapest month to book a flight from St. Louis to Region of Ontario?

What is the cheapest time of day to fly from STL to ON?

Find hourly flight availability from St. Louis to Ontario. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 30 April 2025.

Rainfall in Ontario by month

Plan your trip to Ontario by taking into account the average rainfall totals by month.

Temperature in Ontario by month

Plan your trip to Ontario by taking into account the average temperature totals by month.

Reviews of airlines servicing Ontario

Read through reviews of airlines operating flights from St. Louis to Ontario, such as Delta, United Airlines and American Airlines. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.

Related info for your journey

Find useful and relevant information for your journey from St. Louis to Ontario. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

What airport do you fly from for flights from St. Louis to Ontario?

What are the cheapest airlines to fly from St. Louis to Region of Ontario one-way?

What are the most popular routes from St. Louis to Region of Ontario?

What are the most reliable airlines from St. Louis to Region of Ontario?

What are the cheapest flights from St. Louis to Region of Ontario?

Can I find deals for flights from St. Louis to Ontario that include hotel bookings?

How can I find direct flights from St. Louis to Ontario?

Can I find deals for business class flights from St. Louis to Ontario?

What is the cheapest month to book a flight from St. Louis to Region of Ontario?

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Alternative routes for St. Louis to Ontario

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Top airline flying from St. Louis to Ontario

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Cheapest flights from St. Louis to Ontario
Explore the most affordable flight options available from St. Louis to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 30 April 2025.