$141+ 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 9/25. 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
1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.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 June 12, 2025.
Round-trip from | $302 (Mytrip) |
|---|---|
One-way from | $141 (American Airlines) |
Popular in | March |
Cheapest in | January |
Average price | $397 |
Good round-trip deal | $692 or less |
Good one-way deal | $177 or less |
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 June 12, 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 June 12, 2025.
This Mytrip deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This American Airlines deal was found by Cheapflights users on 6/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This American Airlines deal was found by Cheapflights users on 6/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Sun Country Air deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Sun Country Air is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Air Canada deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This United Airlines deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Delta deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Mytrip deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Mytrip deal was found by Cheapflights users on 6/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Delta deal was found by Cheapflights users on 6/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This United Airlines deal was found by Cheapflights users on 6/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
This Air Canada deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Cheapflights Fare Finder
Customize your flight search to find flights from St. Louis to 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, Cheapflights users made 2,558,603 searches. Data last updated June 12, 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
Wed 7/9
11:24 am-2:05 pm
2 stops25h 41m
Toronto Pearson Intl
Tue 7/15
6:30 am-4:31 pm
1 stop11h 01m
St. LouisToronto
STL - YYZ
STLYYZ
Lambert-St Louis
Mon 9/15
5:55 am-5:49 pm
1 stop10h 54m
Toronto Pearson Intl
Wed 9/17
11:44 am-9:53 pm
1 stop11h 09m
St. LouisToronto
STL - YYZ
STLYYZ
Lambert-St Louis
Sun 6/29
6:12 am-4:50 pm
1 stop9h 38m
Toronto Pearson Intl
Thu 7/3
11:40 am-11:30 am
1 stop24h 50m
St. LouisToronto
STL - YYZ
STLYYZ
Lambert-St Louis
Sun 6/22
7:30 am-10:25 am
Nonstop1h 55m
Toronto Pearson Intl
Thu 6/26
11:30 am-12:36 pm
Nonstop2h 06m
St. LouisToronto
STL - YYZ
STLYYZ
Lambert-St Louis
Thu 9/25
12:25 pm-9:02 pm
1 stop7h 37m
Toronto Pearson Intl
Sun 9/28
2:10 pm-2:27 pm
1 stop25h 17m
St. LouisMontreal
STL - YUL
STLYUL
Lambert-St Louis
Mon 7/14
10:47 am-5:55 pm
2 stops30h 08m
Montreal Pierre Elliott Trudeau Intl
Mon 7/21
8:55 am-4:31 pm
3 stops32h 36m
St. LouisOttawa
STL - YOW
STLYOW
Lambert-St Louis
Wed 7/9
11:24 am-5:06 pm
1 stop28h 42m
Ottawa
Wed 7/16
11:00 am-9:52 am
2 stops23h 52m
St. LouisMontreal
STL - YUL
STLYUL
Lambert-St Louis
Mon 8/11
6:45 pm-10:07 am
1 stop14h 22m
Montreal Pierre Elliott Trudeau Intl
Tue 8/19
6:00 am-8:57 pm
1 stop15h 57m
St. LouisMontreal
STL - YUL
STLYUL
Lambert-St Louis
Mon 8/11
7:59 pm-11:36 am
1 stop14h 37m
Montreal Pierre Elliott Trudeau Intl
Mon 8/18
12:30 pm-11:51 pm
1 stop12h 21m
St. LouisToronto
STL - YYZ
STLYYZ
Lambert-St Louis
Fri 6/27
6:40 am-2:41 pm
1 stop7h 01m
Toronto Pearson Intl
Wed 7/23
11:29 am-4:18 pm
1 stop5h 49m
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?
Currently, January is the cheapest month in which you can book a flight from St. Louis to Region of Ontario (average of $243). Flying from St. Louis to Region of Ontario in July is currently the most expensive (average of $353). 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?
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 June 12, 2025.
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
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 June 12, 2025.
The most flights from STL to CAON are scheduled on a Wednesday (4 on average). You will have fewer flight options on Sunday, which is when the least amount of flights are scheduled (2 on average).
Rainfall in Ontario by month
Plan your trip to Ontario by taking into account the average rainfall totals by month.
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.
Temperature in Ontario by month
Plan your trip to Ontario by taking into account the average temperature totals 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 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).
Reviews of airlines servicing Ontario
Get insights into the airlines that provide service to Ontario. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Ontario. Reviews last updated June 12, 2025.
Peruse reviews from past customers who have flown with Delta, United Airlines and American Airlines from St. Louis to Ontario to help guide your decision. In addition to providing an overall rating, users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Boarding
Food
Crew
Comfort
Overall
Entertainment
Reviews
Kim,May 2025
PIH - SLC
Boarding
Food
Crew
Comfort
Overall
Entertainment
Reviews
Kim,May 2025
PIH - SLC
Boarding
Food
Crew
Comfort
Overall
Entertainment
Reviews
Kim,May 2025
PIH - SLC
Boarding
Food
Crew
Comfort
Overall
Entertainment
Reviews
Kim,May 2025
PIH - SLC
Boarding
Food
Crew
Comfort
Overall
Entertainment
Reviews
Kim,May 2025
PIH - SLC
Boarding
Food
Crew
Comfort
Overall
Entertainment
Reviews
Kim,May 2025
PIH - SLC
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.
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 3 airlines flying from St. Louis to Ontario
Discover the top 3 airlines that operate flights from St. Louis to Ontario. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated June 12, 2025.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$220 | Average$663 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$220 | Average$645 | FlexibilityNo cancel fee | On-time67% | |
| Cheapest$304 | Average$612 | FlexibilityNo cancel fee | On-time71% |