How long is the flight from St. Louis to Region of Ontario?

Departing from St. Louis to Region of Ontario will take you 5h 59m. Airlines will cover a distance of 878 mi. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

In terms of precipitation, rainfall in Region of Ontario ranges from 2.0 - 3.3 inches per month. June is typically the wettest month, when rainfall can reach 3.3 in. February is typically the driest time to visit Region of Ontario when rainfall is around 2.0 in.

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 69.8 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 21.2 F).

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

When deciding which route to take from St. Louis to Region of Ontario consider Lambert-St Louis - Toronto Pearson Intl, Lambert-St Louis - Montreal Pierre Elliott Trudeau Intl or Lambert-St Louis - Ottawa as they are the most popular.

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

Looking for the cheapest flight from St. Louis to Region of Ontario? While on average our users pay $1,431, our data indicates the cheapest price to be $141. The most popular route (Lambert-St Louis - Toronto Pearson Intl), is priced around $294.

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

No one likes to see their flight delayed. When booking a flight from St. Louis to Region of Ontario consider choosing Air Canada (93%), Jazz (93%) or United Airlines (93%) as they are the most reliable in getting you off to your destination on time.

What are the most popular airlines that fly from St. Louis to Region of Ontario?

Air Canada, United Airlines and American Airlines are the most popular airlines when flying from St. Louis to Region of Ontario.

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

Lambert-St Louis (STL) is the airport you will fly out of if you book a flight from St. Louis to Ontario. It is only a 12.7 mi journey to Lambert-St Louis (STL) from St. Louis’s city center.

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.

$108+ Cheap Flights from St. Louis to Ontario

Q: How much does it cost to fly round-trip from St. Louis to Region of Ontario?

Airfare is below average for this route at the moment. St. Louis to Region of Ontario flights typically cost between $475 and $981 in January. The cheapest round-trip price found within the last 3 days was $241 on Multiple Airlines (Jan 14-Jan 17).

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Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

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Cheap flight deals from St. Louis to Ontario

Most accurate provider	eDreams 3 stars
Most trusted provider	eDreams 3 stars
Round-trip from	$241 (Kiwi.com)
One-way from	$108 (Mytrip)
Popular in	March
Cheapest in	January
Average price	$544
Good round-trip deal	$620 or less
Good one-way deal	$179 or less

Provider with most accurate pricing for Lambert-St Louis-Toronto (YTO) flight deals.

Search Deals

Provider most trusted by Cheapflights users for Lambert-St Louis-Toronto (YTO) flights.

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From Lambert-St Louis to Ontario

Search Deals

One-way flight from Lambert-St Louis to Ontario

Search Deals

High demand for flights, 9% potential price rise

Search Deals

Cheapest flight prices on average. 2% potential price decrease ($12 potential savings vs. average RT price).

Search Deals

Average for round-trip flights in October 2025

Search Deals

Price to beat on a round-trip flight from Lambert-St Louis to Ontario.

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

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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 October 29, 2025.

Mon 12/155:15 amSTL - YYZ

1 stop11h 29mAmerican Airlines

Thu 1/81:14 pmYYZ - STL

1 stop9h 01mAmerican Airlines

Deal found 10/27

$276

Mon 12/1510:47 amSTL - YYZ

2 stops36h 24mMultiple Airlines

Thu 1/87:10 amYYZ - STL

1 stop16h 23mMultiple Airlines

Deal found 10/27

$295

Thu 12/43:30 pmSTL - YYZ

1 stop7h 41mMultiple Airlines

Mon 12/812:50 pmYYZ - STL

1 stop10h 43mMultiple Airlines

Deal found 10/28

$301

Mon 11/179:50 amSTL - YYZ

2 stops10h 17mMultiple Airlines

Fri 11/217:00 amYYZ - STL

1 stop26h 57mMultiple Airlines

Deal found 10/28

$316

Thu 12/112:47 pmSTL - YYZ

1 stop22h 53mMultiple Airlines

Sun 12/148:20 pmYYZ - STL

2 stops14h 32mMultiple Airlines

Deal found 10/27

$337

Wed 12/107:43 pmSTL - YYZ

2 stops27h 28mMultiple Airlines

Wed 12/177:10 amYYZ - STL

1 stop16h 23mMultiple Airlines

Deal found 10/27

$354

Mon 11/179:50 amSTL - YYZ

2 stops10h 17mMultiple Airlines

Thu 11/205:15 pmYYZ - STL

1 stop7h 42mMultiple Airlines

Deal found 10/28

$358

Wed 12/1711:50 amSTL - YOW

1 stop9h 06mMultiple Airlines

Fri 12/199:15 amYOW - STL

1 stop7h 14mMultiple Airlines

Deal found 10/28

$359

Fri 12/123:30 pmSTL - YYZ

1 stop19h 13mMultiple Airlines

Mon 12/155:15 pmYYZ - STL

1 stop30h 18mMultiple Airlines

Deal found 10/27

$361

Wed 12/174:05 pmSTL - YOW

1 stop6h 03mAir Canada

Fri 12/1910:20 amYOW - STL

1 stop6h 09mAir Canada

Deal found 10/28

$361

Sun 11/166:21 pmSTL - YYZ

2 stops25h 46mMultiple Airlines

Thu 11/205:15 pmYYZ - STL

1 stop7h 42mMultiple Airlines

Deal found 10/28

$362

Sat 12/136:42 pmSTL - YOW

1 stop14h 44mUnited Airlines

Sat 12/205:59 pmYOW - STL

1 stop6h 34mUnited Airlines

Deal found 10/29

$363

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 October 29, 2025.

Mon 12/155:15 amSTL - YYZ

1 stop11h 29mAmerican Airlines

Thu 1/81:14 pmYYZ - STL

1 stop9h 01mAmerican Airlines

Deal found 10/27

$276

Wed 1/145:06 pmSTL - YYZ

1 stop20h 14mMultiple Airlines

Sat 1/172:20 pmYYZ - STL

2 stops20h 26mMultiple Airlines

Deal found 10/27

$296

Tue 4/74:05 pmSTL - YOW

1 stop5h 59mAir Canada

Wed 4/810:15 amYOW - STL

1 stop6h 09mAir Canada

Deal found 10/27

$361

Sat 12/136:42 pmSTL - YOW

1 stop14h 44mUnited Airlines

Sat 12/205:59 pmYOW - STL

1 stop6h 34mUnited Airlines

Deal found 10/29

$363

Sat 2/146:33 pmSTL - YYZ

1 stop15h 24mAmerican Airlines

Sat 2/2111:38 amYYZ - STL

1 stop7h 25mAmerican Airlines

Deal found 10/26

$279

Mon 11/179:50 amSTL - YYZ

2 stops10h 17mMultiple Airlines

Fri 11/217:00 amYYZ - STL

1 stop26h 57mMultiple Airlines

Deal found 10/28

$316

Sat 2/146:33 pmSTL - YUL

1 stop19h 32mAmerican Airlines

Wed 2/183:55 pmYUL - STL

1 stop18h 38mAmerican Airlines

Deal found 10/29

$291

Sun 2/15:11 pmSTL - YYZ

1 stop20h 09mMultiple Airlines

Tue 2/101:30 pmYYZ - STL

2 stops28h 19mMultiple Airlines

Deal found 10/27

$325

Wed 12/105:05 amSTL - YYZ

1 stop9h 58mAmerican Airlines

Wed 12/176:00 amYYZ - STL

1 stop10h 29mAmerican Airlines

Deal found 10/27

$316

Tue 2/177:41 amSTL - YUL

1 stop12h 36mUnited Airlines

Thu 2/191:10 pmYUL - STL

1 stop10h 49mUnited Airlines

Deal found 10/28

$386

Thu 12/412:04 pmSTL - YYZ

2 stops11h 07mMultiple Airlines

Mon 12/87:15 amYYZ - STL

1 stop16h 18mMultiple Airlines

Deal found 10/28

$325

Thu 2/1912:20 pmSTL - YYZ

1 stop10h 00mMultiple Airlines

Mon 2/238:20 pmYYZ - STL

2 stops38h 42mMultiple Airlines

Deal found 10/27

$331

Wed 12/1710:00 amSTL - YOW

2 stops12h 08mAir Canada

Fri 12/199:15 amYOW - STL

1 stop7h 14mAir Canada

Deal found 10/28

$446

Thu 12/112:47 pmSTL - YYZ

1 stop22h 53mMultiple Airlines

Sun 12/148:20 pmYYZ - STL

2 stops14h 32mMultiple Airlines

Deal found 10/27

$337

Wed 2/189:55 amSTL - YOW

1 stop10h 23mUnited Airlines

Sun 2/226:00 amYOW - STL

2 stops7h 25mUnited Airlines

Deal found 10/27

$449

Tue 2/177:00 amSTL - YYZ

1 stop5h 02mAmerican Airlines

Sat 2/2111:38 amYYZ - STL

1 stop7h 25mAmerican Airlines

Deal found 10/27

$381

Mon 1/129:57 amSTL - YUL

2 stops10h 45mUnited Airlines

Tue 1/131:10 pmYUL - STL

1 stop10h 48mUnited Airlines

Deal found 10/27

$466

Thu 2/267:00 amSTL - YOW

1 stop5h 34mMultiple Airlines

Sun 3/110:20 amYOW - STL

1 stop6h 09mMultiple Airlines

Deal found 10/28

$359

Wed 12/1711:50 amSTL - YOW

1 stop9h 06mMultiple Airlines

Fri 12/199:15 amYOW - STL

1 stop7h 14mMultiple Airlines

Deal found 10/28

$359

Fri 1/168:05 amSTL - YUL

1 stop9h 35mUnited Airlines

Thu 1/221:10 pmYUL - STL

1 stop10h 48mUnited Airlines

Deal found 10/28

$496

Thu 2/512:20 pmSTL - YYZ

1 stop10h 00mMultiple Airlines

Sun 2/88:00 pmYYZ - STL

2 stops15h 02mMultiple Airlines

Deal found 10/27

$363

Wed 2/1811:25 amSTL - YUL

1 stop21h 55mUnited Airlines

Sun 2/221:10 pmYUL - STL

1 stop10h 49mUnited Airlines

Deal found 10/27

$498

Mon 12/157:35 pmSTL - YUL

2 stops17h 14mAmerican Airlines

Tue 1/63:52 pmYUL - STL

1 stop19h 29mAmerican Airlines

Deal found 10/29

$507

Thu 11/137:02 pmSTL - YYZ

1 stop18h 38mMultiple Airlines

Sun 11/167:10 amYYZ - STL

1 stop27h 30mMultiple Airlines

Deal found 10/27

$383

Mon 12/156:42 pmSTL - YUL

1 stop18h 18mUnited Airlines

Tue 1/69:25 amYUL - STL

1 stop12h 48mUnited Airlines

Deal found 10/28

$530

Thu 12/112:47 pmSTL - YUL

1 stop24h 36mMultiple Airlines

Sun 12/144:35 pmYUL - STL

1 stop17h 24mMultiple Airlines

Deal found 10/28

$389

Last-minute flights from St. Louis to Ontario
Discover last-minute flight deals from St. Louis to Ontario. Data last updated October 29, 2025 and is based on user searches.

Thu 11/137:02 pmSTL - YYZ

1 stop18h 38mMultiple Airlines

Sun 11/167:10 amYYZ - STL

1 stop27h 30mMultiple Airlines

Deal found 10/27

$383

Sun 11/166:21 pmSTL - YYZ

2 stops25h 46mMultiple Airlines

Thu 11/205:15 pmYYZ - STL

1 stop7h 42mMultiple Airlines

Deal found 10/28

$362

Mon 11/179:50 amSTL - YYZ

2 stops10h 17mMultiple Airlines

Fri 11/217:00 amYYZ - STL

1 stop26h 57mMultiple Airlines

Deal found 10/28

$316

Mon 11/179:50 amSTL - YYZ

2 stops10h 17mMultiple Airlines

Thu 11/205:15 pmYYZ - STL

1 stop7h 42mMultiple Airlines

Deal found 10/28

$358

Sat 11/226:43 pmSTL - YOW

1 stop14h 43mMultiple Airlines

Thu 11/279:15 amYOW - STL

1 stop7h 14mMultiple Airlines

Deal found 10/28

$590

Tue 11/253:14 pmSTL - YYZ

2 stops31h 41mMultiple Airlines

Tue 12/27:15 amYYZ - STL

1 stop16h 18mMultiple Airlines

Deal found 10/28

$410

Tue 11/256:00 amSTL - YUL

1 stop8h 10mAmerican Airlines

Wed 11/2612:59 pmYUL - STL

2 stops11h 57mAmerican Airlines

Deal found 10/27

$599

Wed 11/2610:24 amSTL - YYZ

1 stop12h 47mMultiple Airlines

Tue 12/27:15 amYYZ - STL

1 stop16h 18mMultiple Airlines

Deal found 10/27

$408

Wed 11/269:50 amSTL - YUL

3 stops12h 32mMultiple Airlines

Wed 12/35:10 pmYUL - STL

2 stops21h 42mMultiple Airlines

Deal found 10/27

$465

Wed 11/266:00 amSTL - YUL

1 stop8h 09mAmerican Airlines

Wed 12/33:50 pmYUL - STL

1 stop17h 18mAmerican Airlines

Deal found 10/28

$508

Thu 11/2710:53 amSTL - YUL

2 stops29h 02mMultiple Airlines

Sun 11/306:00 amYUL - STL

1 stop4h 46mMultiple Airlines

Deal found 10/27

$570

Sun 11/304:13 pmSTL - YYZ

1 stop18h 30mMultiple Airlines

Thu 12/45:15 pmYYZ - STL

1 stop16h 44mMultiple Airlines

Deal found 10/28

$394

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 October 29, 2025.

Thu 2/2612:20 pmSTL - YYZ

1 stop10h 00mMultiple Airlines

Deal found 10/27

$108

Thu 12/45:15 amSTL - YYZ

1 stop9h 48mAmerican Airlines

Deal found 10/28

$110

Thu 12/43:30 pmSTL - YYZ

1 stop7h 41mMultiple Airlines

Deal found 10/29

$130

Mon 12/810:47 amSTL - YYZ

2 stops12h 38mMultiple Airlines

Deal found 10/27

$131

Wed 12/103:30 pmSTL - YYZ

1 stop7h 41mMultiple Airlines

Deal found 10/27

$138

Fri 12/510:42 amSTL - YYZ

2 stops26h 38mMultiple Airlines

Deal found 10/27

$141

Tue 12/93:30 pmSTL - YYZ

1 stop21h 43mMultiple Airlines

Deal found 10/27

$144

Fri 12/510:42 amSTL - YOW

2 stops29h 31mMultiple Airlines

Deal found 10/28

$150

Sun 11/166:21 pmSTL - YYZ

2 stops25h 46mMultiple Airlines

Deal found 10/28

$153

Sat 11/84:33 pmSTL - YOW

1 stop23h 40mMultiple Airlines

Deal found 10/26

$160

Tue 12/93:30 pmSTL - YUL

3 stops47h 53mMultiple Airlines

Deal found 10/29

$181

Fri 11/74:56 pmSTL - YOW

2 stops30h 02mMultiple Airlines

Deal found 10/26

$184

Fly from

Fly to

Route

Depart

Return

Price

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Mon 12/15

5:15 am-5:44 pm

1 stop11h 29m

Toronto Pearson Intl

Thu 1/8

1:14 pm-9:15 pm

1 stop9h 01m

$276

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Sat 2/14

6:33 pm-10:57 am

1 stop15h 24m

Toronto Pearson Intl

Sat 2/21

11:38 am-6:03 pm

1 stop7h 25m

$279

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Sat 2/14

6:33 pm-3:05 pm

1 stop19h 32m

Montreal Pierre Elliott Trudeau Intl

Wed 2/18

3:55 pm-9:33 am

1 stop18h 38m

$291

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Wed 1/14

5:06 pm-2:20 pm

1 stop20h 14m

Toronto Pearson Intl

Sat 1/17

2:20 pm-9:46 am

2 stops20h 26m

$296

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Mon 11/17

9:50 am-9:07 pm

2 stops10h 17m

Toronto Pearson Intl

Fri 11/21

7:00 am-8:57 am

1 stop26h 57m

$316

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Wed 12/10

5:05 am-4:03 pm

1 stop9h 58m

Toronto Pearson Intl

Wed 12/17

6:00 am-3:29 pm

1 stop10h 29m

$316

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Sun 2/1

5:11 pm-2:20 pm

1 stop20h 09m

Toronto Pearson Intl

Tue 2/10

1:30 pm-4:49 pm

2 stops28h 19m

$325

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Thu 12/4

12:04 pm-12:11 am

2 stops11h 07m

Toronto Pearson Intl

Mon 12/8

7:15 am-10:33 pm

1 stop16h 18m

$325

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Thu 2/19

12:20 pm-11:20 pm

1 stop10h 00m

Toronto Pearson Intl

Mon 2/23

8:20 pm-10:02 am

2 stops38h 42m

$331

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Thu 12/11

2:47 pm-2:40 pm

1 stop22h 53m

Toronto Pearson Intl

Sun 12/14

8:20 pm-9:52 am

2 stops14h 32m

$337

Flights are sorted by cheapest round-trip flights first.

Deals found on 10/29

Showing 1-10 of 39 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, June is the cheapest month in which you can book a flight from St. Louis to Region of Ontario (average of $179). Flying from St. Louis to Region of Ontario in February is currently the most expensive (average of $361). 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.

How much does it cost to fly round-trip from St. Louis to Region of Ontario?

Reviews of airlines servicing Ontario

Get a feel of what it's like to fly with Delta, United Airlines, and American Airlines from St. Louis to Ontario by reading reviews from past customers. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.

Delta

7.9

Good

7,994 reviews

Reviews

1 / 20

8.0

Excellent

Matthew,Oct 2025

GSP - ATL

This is always a full flight since it is the connecting route to primary destinations through Atlanta. That said, the crew handles the full load well. Not much more to say, it is a short flight with no in-flight services due to the length.

Delta

7.9

Good

7,994 reviews

Delta

7.9

Good

7,994 reviews

Reviews

1 / 20

8.0

Excellent

Matthew,Oct 2025

GSP - ATL

United Airlines

7.4

Good

9,001 reviews

Delta

7.9

Good

7,994 reviews

Reviews

1 / 20

8.0

Excellent

Matthew,Oct 2025

GSP - ATL

American Airlines

7.2

Good

11,032 reviews

Delta

7.9

Good

7,994 reviews

Reviews

1 / 20

8.0

Excellent

Matthew,Oct 2025

GSP - ATL

Air Canada

7.1

Good

10,371 reviews

Delta

7.9

Good

7,994 reviews

Reviews

1 / 20

8.0

Excellent

Matthew,Oct 2025

GSP - ATL

Related info for your journey

What airport do you fly from for flights from St. Louis to Ontario?
Lambert-St Louis (STL) is the airport you will fly out of if you book a flight from St. Louis to Ontario. It is only a 12.7 mi journey to Lambert-St Louis (STL) from St. Louis’s city center.
How long is the flight from St. Louis to Region of Ontario?
Departing from St. Louis to Region of Ontario will take you 5h 59m. Airlines will cover a distance of 878 mi. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.
What are the most popular routes from St. Louis to Region of Ontario?
When deciding which route to take from St. Louis to Region of Ontario consider Lambert-St Louis - Toronto Pearson Intl, Lambert-St Louis - Montreal Pierre Elliott Trudeau Intl or Lambert-St Louis - Ottawa as they are the most popular.
What are the most reliable airlines from St. Louis to Region of Ontario?
No one likes to see their flight delayed. When booking a flight from St. Louis to Region of Ontario consider choosing Air Canada (93%), Jazz (93%) or United Airlines (93%) as they are the most reliable in getting you off to your destination on time.
What are the cheapest flights from St. Louis to Region of Ontario?
Looking for the cheapest flight from St. Louis to Region of Ontario? While on average our users pay $1,431, our data indicates the cheapest price to be $141. The most popular route (Lambert-St Louis - Toronto Pearson Intl), is priced around $294.
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, June is the cheapest month in which you can book a flight from St. Louis to Region of Ontario (average of $179). Flying from St. Louis to Region of Ontario in February is currently the most expensive (average of $361). 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

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Complete your trip

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Top 3 airlines flying from St. Louis to Ontario

Airline	Cheapest	Average	Flexibility	On-time
United Airlines	Cheapest$214	Average$676	FlexibilityNo cancel fee	On-time69%
Air Canada	Cheapest$221	Average$682	FlexibilityNo cancel fee	On-time67%
American Airlines	Cheapest$391	Average$612	FlexibilityNo cancel fee	On-time71%

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$108+ Cheap flights from St. Louis (STL) to Ontario

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 2/26. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from St. Louis to Ontario with Cheapflights

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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 October 29, 2025.

Most accurate provider

Most trusted provider

Round-trip from

One-way from

Popular in

Cheapest in

Average price

Good round-trip deal

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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 October 29, 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 October 29, 2025.

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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.

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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 October 29, 2025.

How much does it cost to fly round-trip from St. Louis to Region of Ontario?

Reviews of airlines servicing Ontario

Get a feel of what it's like to fly with Delta, United Airlines, and American Airlines from St. Louis to Ontario by reading reviews from past customers. You can also see how each airline compares in terms of 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?

How long is the flight from St. Louis to Region of Ontario?

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 3 airlines 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 October 29, 2025.