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$ 273. Users have also found prices from C$ 281 and C$ 291 on Air Canada and United Airlines, 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 (73%), Jazz (73%), United Airlines( 73%).

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 233% 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$ 479. For sooner than that we have options available in the next 3 days from C$ 672.

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$ 594 per person but you can even find prices for as low as C$ 324. The most expensive prices can be found in the month of February. Opting for a May flight can save you 56% on your journey compared to booking in February

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$ 99+ Flights from St. Louis to Ontario

Cheap flight deals from St. Louis to Ontario

Round-trip from	C$ 305
One-way from	C$ 99
Popular in	February
Cheapest in	May
Average price	C$ 928

1/4-3/4
2 total stops
39h 55m total
St. Louis to Ontario

Search Deals

27/3
1 total stop
28h 08m total
St. Louis to Ontario

Search Deals

Highest demand for flights based on searches. 15% potential increase in price (C$ 160 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 5% potential price decrease (C$ 44 potential savings vs. average RT price).

Search Deals

Average for round-trip flights in February 2025

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 20 February 2025.

Tue 1/46:47 p.m.STL - YYZ

1 stop28h 08mMultiple Airlines

Thu 3/47:05 a.m.YYZ - STL

1 stop11h 47mMultiple Airlines

Deal found 19/2C$ 305

Thu 10/46:11 p.m.STL - YUL

1 stop19h 44mMultiple Airlines

Sun 13/46:45 a.m.YUL - STL

2 stops11h 31mMultiple Airlines

Deal found 20/2C$ 402

Mon 31/39:30 a.m.STL - YYZ

1 stop10h 01mDelta

Mon 7/46:14 a.m.YYZ - STL

1 stop9h 32mDelta

Deal found 20/2C$ 616

Mon 31/36:10 a.m.STL - YUL

1 stop9h 18mDelta

Mon 7/46:00 a.m.YUL - STL

1 stop9h 46mDelta

Deal found 20/2C$ 635

Mon 24/35:55 a.m.STL - YYZ

1 stop10h 35mAmerican Airlines

Fri 28/311:30 a.m.YYZ - STL

1 stop7h 29mAmerican Airlines

Deal found 20/2C$ 651

Thu 20/35:33 p.m.STL - YYZ

1 stop5h 26mAir Canada

Thu 27/39:00 a.m.YYZ - STL

1 stop4h 12mAir Canada

Deal found 20/2C$ 663

Sun 6/44:57 p.m.STL - YXU

1 stop17h 23mMultiple Airlines

Sun 13/48:00 p.m.YXU - STL

2 stops22h 56mMultiple Airlines

Deal found 20/2C$ 687

Wed 23/49:39 a.m.STL - YYZ

1 stop8h 03mUnited Airlines

Sat 26/48:00 a.m.YYZ - STL

2 stops13h 04mUnited Airlines

Deal found 19/2C$ 689

Fri 4/45:00 p.m.STL - YUL

1 stop15h 50mAmerican Airlines

Sat 5/412:30 p.m.YUL - STL

1 stop10h 42mAmerican Airlines

Deal found 20/2C$ 696

Fri 23/55:40 p.m.STL - YYZ

1 stop5h 17mWestJet

Sun 25/56:00 a.m.YYZ - STL

1 stop4h 31mWestJet

Deal found 18/2C$ 788

Fri 2/55:29 p.m.STL - YUL

2 stops22h 29mUnited Airlines

Sun 4/56:40 p.m.YUL - STL

1 stop22h 07mUnited Airlines

Deal found 20/2C$ 788

Fri 2/51:30 p.m.STL - YUL

Nonstop2h 30mAir Canada

Sun 4/56:10 p.m.YUL - STL

Nonstop2h 51mAir Canada

Deal found 20/2C$ 811

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 20 February 2025.

Tue 1/46:47 p.m.STL - YYZ

1 stop28h 08mMultiple Airlines

Thu 3/47:05 a.m.YYZ - STL

1 stop11h 47mMultiple Airlines

Deal found 19/2C$ 305

Mon 31/39:30 a.m.STL - YYZ

1 stop10h 01mDelta

Mon 7/46:14 a.m.YYZ - STL

1 stop9h 32mDelta

Deal found 20/2C$ 616

Mon 24/35:55 a.m.STL - YYZ

1 stop10h 35mAmerican Airlines

Fri 28/311:30 a.m.YYZ - STL

1 stop7h 29mAmerican Airlines

Deal found 20/2C$ 651

Thu 20/35:33 p.m.STL - YYZ

1 stop5h 26mAir Canada

Thu 27/39:00 a.m.YYZ - STL

1 stop4h 12mAir Canada

Deal found 20/2C$ 663

Wed 23/49:39 a.m.STL - YYZ

1 stop8h 03mUnited Airlines

Sat 26/48:00 a.m.YYZ - STL

2 stops13h 04mUnited Airlines

Deal found 19/2C$ 689

Fri 23/55:40 p.m.STL - YYZ

1 stop5h 17mWestJet

Sun 25/56:00 a.m.YYZ - STL

1 stop4h 31mWestJet

Deal found 18/2C$ 788

Thu 10/46:11 p.m.STL - YUL

1 stop19h 44mMultiple Airlines

Sun 13/46:45 a.m.YUL - STL

2 stops11h 31mMultiple Airlines

Deal found 20/2C$ 402

Wed 19/36:15 a.m.STL - YYZ

2 stops31h 40mAlaska Airlines

Wed 26/34:20 p.m.YYZ - STL

2 stops17h 28mAlaska Airlines

Deal found 19/2C$ 1,101

Mon 31/36:10 a.m.STL - YUL

1 stop9h 18mDelta

Mon 7/46:00 a.m.YUL - STL

1 stop9h 46mDelta

Deal found 20/2C$ 635

Fri 4/45:00 p.m.STL - YUL

1 stop15h 50mAmerican Airlines

Sat 5/412:30 p.m.YUL - STL

1 stop10h 42mAmerican Airlines

Deal found 20/2C$ 696

Sun 6/44:57 p.m.STL - YXU

1 stop17h 23mMultiple Airlines

Sun 13/48:00 p.m.YXU - STL

2 stops22h 56mMultiple Airlines

Deal found 20/2C$ 687

Fri 2/55:29 p.m.STL - YUL

2 stops22h 29mUnited Airlines

Sun 4/56:40 p.m.YUL - STL

1 stop22h 07mUnited Airlines

Deal found 20/2C$ 788

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 20 February 2025.

Sat 5/74:05 p.m.STL - YYZ

Nonstop1h 55mAir Canada

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

Nonstop2h 06mAir Canada

Deal found 20/2C$ 719

Mon 24/33:50 p.m.STL - YYZ

Nonstop1h 55mUnited Airlines

Fri 28/31:50 p.m.YYZ - STL

Nonstop2h 16mUnited Airlines

Deal found 20/2C$ 743

Fri 2/51:30 p.m.STL - YUL

Nonstop2h 30mAir Canada

Sun 4/56:10 p.m.YUL - STL

Nonstop2h 51mAir Canada

Deal found 20/2C$ 811

Fri 20/61:30 p.m.STL - YUL

Nonstop2h 30mMultiple Airlines

Sun 29/66:10 p.m.YUL - STL

Nonstop2h 50mMultiple Airlines

Deal found 20/2C$ 1,108

Last-minute flights from St. Louis to Ontario
Discover last-minute flight deals from St. Louis to Ontario. Data last updated 20 February 2025 and is based on user searches.

Sun 2/36:43 a.m.STL - YYZ

1 stop8h 26mWestJet

Thu 6/36:00 a.m.YYZ - STL

1 stop4h 36mWestJet

Deal found 19/2C$ 1,034

Sun 2/36:30 a.m.STL - YYZ

1 stop6h 12mAir Canada

Thu 6/31:50 p.m.YYZ - STL

Nonstop2h 16mAir Canada

Deal found 19/2C$ 1,135

Sun 2/35:50 p.m.STL - YYZ

1 stop3h 59mDelta

Thu 6/36:15 a.m.YYZ - STL

2 stops10h 19mDelta

Deal found 19/2C$ 1,249

Mon 10/33:50 p.m.STL - YUL

1 stop6h 58mAir Canada

Thu 13/38:15 a.m.YUL - STL

1 stop7h 51mAir Canada

Deal found 20/2C$ 1,045

Wed 19/35:24 p.m.STL - YYZ

1 stop17h 21mMultiple Airlines

Wed 26/32:00 p.m.YYZ - STL

2 stops10h 49mMultiple Airlines

Deal found 19/2C$ 408

Wed 19/36:15 a.m.STL - YYZ

2 stops31h 40mAlaska Airlines

Wed 26/34:20 p.m.YYZ - STL

2 stops17h 28mAlaska Airlines

Deal found 19/2C$ 1,101

Thu 20/35:33 p.m.STL - YYZ

1 stop5h 26mAir Canada

Thu 27/39:00 a.m.YYZ - STL

1 stop4h 12mAir Canada

Deal found 20/2C$ 663

Thu 20/37:29 a.m.STL - YUL

1 stop8h 30mAmerican Airlines

Thu 27/310:54 a.m.YUL - STL

1 stop10h 00mAmerican Airlines

Deal found 20/2C$ 726

Fri 21/36:10 a.m.STL - YYZ

1 stop9h 01mWestJet

Fri 21/36:15 p.m.YYZ - STL

1 stop16h 29mWestJet

Deal found 19/2C$ 852

Mon 24/35:55 a.m.STL - YYZ

1 stop10h 35mAmerican Airlines

Fri 28/311:30 a.m.YYZ - STL

1 stop7h 29mAmerican Airlines

Deal found 20/2C$ 651

Sun 30/36:30 a.m.STL - YUL

2 stops10h 05mUnited Airlines

Fri 4/46:00 a.m.YUL - STL

2 stops9h 42mUnited Airlines

Deal found 20/2C$ 1,143

Mon 31/35:24 p.m.STL - YUL

2 stops30h 15mMultiple Airlines

Mon 7/43:55 p.m.YUL - STL

1 stop26h 57mMultiple Airlines

Deal found 20/2C$ 450

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 20 February 2025.

Thu 27/36:47 p.m.STL - YYZ

1 stop28h 08mMultiple Airlines

Deal found 19/2C$ 99

Tue 25/36:10 a.m.STL - YUL

1 stop9h 18mDelta

Deal found 20/2C$ 273

Sat 22/35:33 p.m.STL - YYZ

1 stop5h 26mAir Canada

Deal found 19/2C$ 281

Sat 5/46:30 a.m.STL - YYZ

2 stops12h 18mUnited Airlines

Deal found 19/2C$ 291

Fri 25/49:39 a.m.STL - YUL

1 stop8h 12mUnited Airlines

Deal found 20/2C$ 358

Thu 6/33:50 p.m.STL - YUL

1 stop9h 03mAir Canada

Deal found 20/2C$ 729

Find flights from St. Louis to Ontario within your budget

Fly from

Fly to

Route

Depart

Return

Price

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Tue 1/4

6:47 p.m.-11:55 p.m.

1 stop28h 08m

Toronto Pearson Intl

Thu 3/4

7:05 a.m.-5:52 p.m.

1 stop11h 47m

C$ 305

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Thu 10/4

6:11 p.m.-2:55 p.m.

1 stop19h 44m

Montreal Pierre Elliott Trudeau Intl

Sun 13/4

6:45 a.m.-5:16 p.m.

2 stops11h 31m

C$ 402

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Mon 31/3

9:30 a.m.-8:31 p.m.

1 stop10h 01m

Toronto Pearson Intl

Mon 7/4

6:14 a.m.-2:46 p.m.

1 stop9h 32m

C$ 616

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Mon 31/3

6:10 a.m.-4:28 p.m.

1 stop9h 18m

Montreal Pierre Elliott Trudeau Intl

Mon 7/4

6:00 a.m.-2:46 p.m.

1 stop9h 46m

C$ 635

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Mon 24/3

5:55 a.m.-5:30 p.m.

1 stop10h 35m

Toronto Pearson Intl

Fri 28/3

11:30 a.m.-5:59 p.m.

1 stop7h 29m

C$ 651

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Thu 20/3

5:33 p.m.-11:59 p.m.

1 stop5h 26m

Toronto Pearson Intl

Thu 27/3

9:00 a.m.-12:12 p.m.

1 stop4h 12m

C$ 663

St. LouisLondon

STL - YXU

STLYXU

Lambert-St Louis

Sun 6/4

4:57 p.m.-11:20 a.m.

1 stop17h 23m

London

Sun 13/4

8:00 p.m.-5:56 p.m.

2 stops22h 56m

C$ 687

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Wed 23/4

9:39 a.m.-6:42 p.m.

1 stop8h 03m

Toronto Pearson Intl

Sat 26/4

8:00 a.m.-8:04 p.m.

2 stops13h 04m

C$ 689

St. LouisMontreal

STL - YUL

STLYUL

Lambert-St Louis

Fri 4/4

5:00 p.m.-9:50 a.m.

1 stop15h 50m

Montreal Pierre Elliott Trudeau Intl

Sat 5/4

12:30 p.m.-10:12 p.m.

1 stop10h 42m

C$ 696

St. LouisToronto

STL - YYZ

STLYYZ

Lambert-St Louis

Fri 23/5

5:40 p.m.-11:57 p.m.

1 stop5h 17m

Toronto Pearson Intl

Sun 25/5

6:00 a.m.-9:31 a.m.

1 stop4h 31m

C$ 788

Flights are sorted by cheapest round-trip flights first.

Deals found on 19/2

Showing 1-10 of 22 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.

Travel insights for flights from St. Louis to Ontario

Get recent, data-driven insights about flights from St. Louis to Ontario including ideal travel times, pricing trends, and more.

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.

Weekly flight availability from St. Louis to Region of Ontario

The most flights from STL to CAON are scheduled on a Wednesday (2 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (1 on average).

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 Alaska Airlines, Delta and United Airlines. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.

Alaska Airlines

8.0

Very good

9,692 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

Alaska Airlines

8.0

Very good

9,692 reviews

Alaska Airlines

8.0

Very good

9,692 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

Delta

8.0

Very good

8,220 reviews

Alaska Airlines

8.0

Very good

9,692 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

United Airlines

7.4

Good

8,766 reviews

Alaska Airlines

8.0

Very good

9,692 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

American Airlines

7.2

Good

10,000 reviews

Alaska Airlines

8.0

Very good

9,692 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

WestJet

7.2

Good

2,801 reviews

Alaska Airlines

8.0

Very good

9,692 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

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$ 273. Users have also found prices from C$ 281 and C$ 291 on Air Canada and United Airlines, 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 (73%), Jazz (73%), United Airlines( 73%).
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

London Airport car rentals

Toronto Region of Waterloo Intl 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$ 366	AverageC$ 793	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.

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.

Cheap flights from St. Louis to Ontario from C$ 99

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 27/3. 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 20 February 2025.

Round-trip from

One-way from

Popular in

Cheapest in

Average price

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 20 February 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 20 February 2025.

Find flights from St. Louis to Ontario within your budget

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.

Travel insights for flights from St. Louis to Ontario

Get recent, data-driven insights about flights from St. Louis to Ontario including ideal travel times, pricing trends, and more.

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 20 February 2025.

Weekly flight availability from St. Louis to Region of Ontario

Explore weekly flight availability from St. Louis to Ontario. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated 20 February 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 Alaska Airlines, Delta and United 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?

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?

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for St. Louis to Ontario

See prices for flight routes from nearby airports that may be better suited for you.

Top airline flying from St. Louis to Ontario

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travelers can enjoy low prices and a wide availability of flights to their desired destinations.

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

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

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

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

100% Free

Book with Flexibility

Travel Smart

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 20 February 2025.