$71+ Cheap flights from Ontario to St. Louis (ONT - STL)
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 10/20. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — STL
Aug 31 — Sep 71
Round-trip
1 adult, Economy
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Find cheap flights from Ontario to St. Louis 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 Ontario to St. Louis
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Best
Last-minute
One-way
Cheapest flights from Ontario to St. LouisExplore the most affordable flight options available from Ontario to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 1, 2026.
Explore the most affordable flight options available from Ontario to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 1, 2026.
This Kiwi.com deal was found by Cheapflights users on 7/30. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/96:15 am
ONT
- STL
1 stop11h 02m
Frontier
Wed 9/168:10 pm
STL
- ONT
1 stop16h 20m
Frontier
Deal found 7/30![Frontier logo]()
$140
This Kiwi.com deal was found by Cheapflights users on 7/30. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/2410:49 am
ONT
- STL
1 stop6h 24m
Frontier
Thu 8/275:27 pm
STL
- ONT
1 stop17h 11m
Frontier
Deal found 7/30![Frontier logo]()
$220
This Kiwi.com deal was found by Cheapflights users on 8/1. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/116:15 am
ONT
- STL
1 stop11h 02m
Frontier
Sat 9/1912:17 pm
STL
- ONT
2 stops13h 30m
Frontier
Deal found 8/1![Frontier logo]()
$226
This Kiwi.com deal was found by Cheapflights users on 7/30. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/176:45 pm
ONT
- STL
2 stops16h 25m
Frontier
Sun 9/208:10 pm
STL
- ONT
1 stop29h 37m
Frontier
Deal found 7/30![Frontier logo]()
$239
This Frontier deal was found by Cheapflights users on 7/27. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/1611:45 am
ONT
- STL
1 stop5h 32m
Frontier
Sat 9/2612:17 pm
STL
- ONT
1 stop6h 17m
Frontier
Deal found 7/27![Frontier logo]()
$248
Best flights from Ontario to St. LouisDiscover carefully curated flight deals from Ontario to St. Louis that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated August 1, 2026.
Discover carefully curated flight deals from Ontario to St. Louis that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated August 1, 2026.
This Frontier deal was found by Cheapflights users on 7/29. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/203:40 pm
ONT
- STL
1 stop24h 10m
Frontier
Wed 8/266:45 pm
STL
- ONT
1 stop15h 18m
Frontier
Deal found 7/29![Frontier logo]()
$249
This United Airlines deal was found by Cheapflights users on 7/27. 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.
Tue 8/189:15 am
ONT
- STL
1 stop6h 49m
United Airlines
Wed 8/191:36 pm
STL
- ONT
2 stops8h 25m
United Airlines
Deal found 7/27![United Airlines logo]()
$372
This Southwest deal was found by Cheapflights users on 7/30. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/268:35 am
ONT
- STL
2 stops7h 20m
Southwest
Sat 8/298:55 am
STL
- ONT
2 stops8h 20m
Southwest
Deal found 7/30![Southwest logo]()
$377
This KAYAK deal was found by Cheapflights users on 7/29. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/245:05 pm
ONT
- STL
1 stop5h 36m
Delta
Thu 8/276:00 am
STL
- ONT
1 stop6h 42m
Delta
Deal found 7/29![Delta logo]()
$417
This Frontier deal was found by Cheapflights users on 7/27. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/1611:45 am
ONT
- STL
1 stop5h 32m
Frontier
Sun 9/2010:20 am
STL
- ONT
1 stop10h 19m
Frontier
Deal found 7/27![Frontier logo]()
$288
This Southwest deal was found by Cheapflights users on 7/29. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/175:15 am
ONT
- STL
2 stops10h 05m
Southwest
Sat 9/198:55 am
STL
- ONT
2 stops8h 20m
Southwest
Deal found 7/29![Southwest logo]()
$414
This Delta deal was found by Cheapflights users on 7/29. 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.
Tue 9/226:00 pm
ONT
- STL
2 stops12h 40m
Delta
Thu 9/242:25 pm
STL
- ONT
2 stops10h 15m
Delta
Deal found 7/29![Delta logo]()
$463
This Southwest deal was found by Cheapflights users on 7/29. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/224:55 pm
ONT
- STL
1 stop5h 50m
Southwest
Tue 12/297:40 am
STL
- ONT
2 stops10h 00m
Southwest
Deal found 7/29![Southwest logo]()
$428
This Delta deal was found by Cheapflights users on 7/29. 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.
Fri 12/2512:00 pm
ONT
- STL
1 stop9h 39m
Delta
Thu 12/316:00 am
STL
- ONT
1 stop7h 27m
Delta
Deal found 7/29![Delta logo]()
$468
This Southwest deal was found by Cheapflights users on 7/27. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/175:15 am
ONT
- STL
2 stops10h 05m
Southwest
Tue 8/1811:55 am
STL
- ONT
2 stops7h 55m
Southwest
Deal found 7/27![Southwest logo]()
$450
Last-minute flights from Ontario to St. LouisDiscover last-minute flight deals from Ontario to St. Louis. Data last updated August 1, 2026 and is based on user searches.
Discover last-minute flight deals from Ontario to St. Louis. Data last updated August 1, 2026 and is based on user searches.
This Vliegwinkel deal was found by Cheapflights users on 7/27. 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 Vliegwinkel is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/1711:47 am
ONT
- STL
1 stop28h 03m
Frontier
Mon 8/247:58 pm
STL
- ONT
1 stop5h 52m
Frontier
Deal found 7/27![Frontier logo]()
$253
This CheapOair deal was found by Cheapflights users on 7/27. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/1711:47 am
ONT
- STL
1 stop28h 03m
Frontier
Thu 8/206:45 pm
STL
- ONT
1 stop23h 37m
Frontier
Deal found 7/27![Frontier logo]()
$258
This Frontier deal was found by Cheapflights users on 7/30. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/208:17 am
ONT
- STL
1 stop6h 14m
Frontier
Thu 8/277:58 pm
STL
- ONT
1 stop5h 52m
Frontier
Deal found 7/30![Frontier logo]()
$248
This Frontier deal was found by Cheapflights users on 7/29. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/203:40 pm
ONT
- STL
1 stop24h 10m
Frontier
Wed 8/266:45 pm
STL
- ONT
1 stop15h 18m
Frontier
Deal found 7/29![Frontier logo]()
$249
This Booking.com deal was found by Cheapflights users on 7/28. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/208:17 am
ONT
- STL
1 stop6h 14m
Frontier
Tue 8/256:45 pm
STL
- ONT
1 stop23h 09m
Frontier
Deal found 7/28![Frontier logo]()
$256
This Kiwi.com deal was found by Cheapflights users on 7/30. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/2410:49 am
ONT
- STL
1 stop6h 24m
Frontier
Thu 8/275:27 pm
STL
- ONT
1 stop17h 11m
Frontier
Deal found 7/30![Frontier logo]()
$220
This Gotogate deal was found by Cheapflights users on 7/29. 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 Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/2410:49 am
ONT
- STL
1 stop6h 24m
Frontier
Wed 8/266:45 pm
STL
- ONT
1 stop23h 37m
Frontier
Deal found 7/29![Frontier logo]()
$254
This Kiwi.com deal was found by Cheapflights users on 7/30. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/276:00 am
ONT
- STL
1 stop11h 13m
Frontier
Thu 9/36:17 pm
STL
- ONT
2 stops40h 19m
Frontier
Deal found 7/30![Frontier logo]()
$257
One-way flights from Ontario to St. LouisSearch for one-way flight options from Ontario to St. Louis. Find affordable one-way fares based on user searches. Data last updated August 1, 2026.
Search for one-way flight options from Ontario to St. Louis. Find affordable one-way fares based on user searches. Data last updated August 1, 2026.
This Trip.com deal was found by Cheapflights users on 7/28. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/206:00 am
ONT
- STL
1 stop11h 15m
Frontier
Deal found 7/28![Frontier logo]()
$71
This Trip.com deal was found by Cheapflights users on 7/29. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/146:15 am
ONT
- STL
1 stop11h 02m
Frontier
Deal found 7/29![Frontier logo]()
$88
This Trip.com deal was found by Cheapflights users on 7/29. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/36:00 am
ONT
- STL
1 stop11h 13m
Frontier
Deal found 7/29![Frontier logo]()
$105
This Super.com deal was found by Cheapflights users on 7/29. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/1211:45 am
ONT
- STL
1 stop5h 32m
Frontier
Deal found 7/29![Frontier logo]()
$123
This Priceline deal was found by Cheapflights users on 7/30. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/208:17 am
ONT
- STL
1 stop6h 14m
Frontier
Deal found 7/30![Frontier logo]()
$124
This Frontier deal was found by Cheapflights users on 7/31. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/911:45 am
ONT
- STL
1 stop5h 32m
Frontier
Deal found 7/31![Frontier logo]()
$126
This Frontier deal was found by Cheapflights users on 7/31. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/711:45 am
ONT
- STL
1 stop5h 32m
Frontier
Deal found 7/31![Frontier logo]()
$127
This Super.com deal was found by Cheapflights users on 7/30. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/172:30 pm
ONT
- STL
1 stop18h 57m
Frontier
Deal found 7/30![Frontier logo]()
$128
This Super.com deal was found by Cheapflights users on 7/27. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/183:40 pm
ONT
- STL
1 stop24h 10m
Frontier
Deal found 7/27![Frontier logo]()
$129
This Mytrip deal was found by Cheapflights users on 7/28. 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.
Tue 9/225:44 pm
ONT
- STL
1 stop15h 48m
Frontier
Deal found 7/28![Frontier logo]()
$130
This Trip.com deal was found by Cheapflights users on 7/29. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/197:56 pm
ONT
- STL
1 stop21h 17m
Frontier
Deal found 7/29![Frontier logo]()
$134
Find flight deals from Ontario to St. Louis
Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to St. Louis (STL). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated August 1, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $140 (Kiwi.com) |
One-way from | $71 (Trip.com) |
Popular in | July |
Cheapest in | April |
Average price | $325 |
Cheapflights Fare Finder
Customize your flight search to find flights from Ontario to St. Louis 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 August 1, 2026.
Use the filters below to find and compare flights from Ontario to St. Louis that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
OntarioSt. Louis
ONT - STL
ONTSTL
Ontario
Thu 8/20
3:40 pm-5:50 pm
1 stop24h 10m
Lambert-St Louis
Wed 8/26
6:45 pm-8:03 am
1 stop15h 18m
$249
OntarioSt. Louis
ONT - STL
ONTSTL
Ontario
Wed 9/16
11:45 am-7:17 pm
1 stop5h 32m
Lambert-St Louis
Sun 9/20
10:20 am-6:39 pm
1 stop10h 19m
$288
OntarioSt. Louis
ONT - STL
ONTSTL
Ontario
Tue 8/18
9:15 am-6:04 pm
1 stop6h 49m
Lambert-St Louis
Wed 8/19
1:36 pm-8:01 pm
2 stops8h 25m
$372
OntarioSt. Louis
ONT - STL
ONTSTL
Ontario
Wed 8/26
8:35 am-5:55 pm
2 stops7h 20m
Lambert-St Louis
Sat 8/29
8:55 am-3:15 pm
2 stops8h 20m
$377
OntarioSt. Louis
ONT - STL
ONTSTL
Ontario
Thu 9/17
5:15 am-5:20 pm
2 stops10h 05m
Lambert-St Louis
Sat 9/19
8:55 am-3:15 pm
2 stops8h 20m
$414
Quickest round-trip
OntarioSt. Louis
ONT - STL
ONTSTL
Ontario
Mon 8/24
5:05 pm-12:41 am
1 stop5h 36m
Lambert-St Louis
Thu 8/27
6:00 am-10:42 am
1 stop6h 42m
$417
OntarioSt. Louis
ONT - STL
ONTSTL
Ontario
Tue 12/22
4:55 pm-12:45 am
1 stop5h 50m
Lambert-St Louis
Tue 12/29
7:40 am-3:40 pm
2 stops10h 00m
$428
OntarioSt. Louis
ONT - STL
ONTSTL
Ontario
Mon 8/17
5:15 am-5:20 pm
2 stops10h 05m
Lambert-St Louis
Tue 8/18
11:55 am-5:50 pm
2 stops7h 55m
$450
OntarioSt. Louis
ONT - STL
ONTSTL
Ontario
Tue 9/22
6:00 pm-8:40 am
2 stops12h 40m
Lambert-St Louis
Thu 9/24
2:25 pm-10:40 pm
2 stops10h 15m
$463
OntarioSt. Louis
ONT - STL
ONTSTL
Ontario
Fri 12/25
12:00 pm-11:39 pm
1 stop9h 39m
Lambert-St Louis
Thu 12/31
6:00 am-11:27 am
1 stop7h 27m
$468
Showing 1-10 of 22 resultsSorted by cheapest first
Compare providers for flights from Ontario to St. Louis
Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Ontario to St. Louis in August.
| Provider | Price Accuracy | Trust Score* |
|---|---|---|
| Price Accuracy1 star | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy- | Trust Score*1 star |
- Most accurate provider: When it comes to deals on Ontario-St. Louis flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ontario-St. Louis flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ontario-St. Louis flight searches over the past month and is updated monthly.
- Most trusted provider: When it comes to deals on Ontario-St. Louis flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Ontario-St. Louis flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.
Best time to book a flight from Ontario to St. Louis
Have a flexible travel schedule? Discover the best time to fly to St. Louis from Ontario with our price prediction graph.
ONT-STL
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 Ontario to St. Louis
How far ahead should I book a flight from Ontario to St. Louis?
The best time to book flights from Ontario to St. Louis is 81 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.
What is the cheapest month to book a flight from Ontario to St. Louis?
Currently, April is the cheapest month in which you can book a flight from Ontario to St. Louis (average of $250). Flying from Ontario to St. Louis in July is currently the most expensive (average of $622). 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.
How much does it cost to fly round-trip from Ontario to St. Louis?
Airfare is below average for this route at the moment.
Ontario to St. Louis flights typically cost between $268 and $403 in September.The cheapest round-trip price found within the last 5 days was $140 on Frontier (Sep 9-Sep 16).
Reviews of airlines servicing St. Louis
Get insights into the airlines that provide service to St. Louis. 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 St. Louis. Reviews last updated August 1, 2026.
Get a feel of what it's like to fly with Southwest,Delta, andUnited Airlines from Ontario to St. Louis by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Comfort
8.0
Boarding
8.1
Overall
8.0
Food
7.0
Entertainment
7.5
Crew
8.6
Reviews
1 / 20
8.0
ExcellentLa Tracimeldamarcos,Jun 2026
LAX - SLC
Comfort
8.0
Boarding
8.1
Overall
8.0
Food
7.0
Entertainment
7.5
Crew
8.6
Reviews
1 / 20
8.0
ExcellentLa Tracimeldamarcos,Jun 2026
LAX - SLC
Comfort
8.0
Boarding
8.1
Overall
8.0
Food
7.0
Entertainment
7.5
Crew
8.6
Reviews
1 / 20
8.0
ExcellentLa Tracimeldamarcos,Jun 2026
LAX - SLC
Comfort
8.0
Boarding
8.1
Overall
8.0
Food
7.0
Entertainment
7.5
Crew
8.6
Reviews
1 / 20
8.0
ExcellentLa Tracimeldamarcos,Jun 2026
LAX - SLC
Comfort
8.0
Boarding
8.1
Overall
8.0
Food
7.0
Entertainment
7.5
Crew
8.6
Reviews
1 / 20
8.0
ExcellentLa Tracimeldamarcos,Jun 2026
LAX - SLC
Comfort
8.0
Boarding
8.1
Overall
8.0
Food
7.0
Entertainment
7.5
Crew
8.6
Reviews
1 / 20
8.0
ExcellentLa Tracimeldamarcos,Jun 2026
LAX - SLC
Related info for your journey
Find useful and relevant information for your journey from Ontario to St. Louis. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
Traveling to a place near St. Louis?
Book flights to St. Louis if you plan to visit one of these locationsEdwardsville
O'Fallon
Fenton
Swansea
Fairview Heights
Eureka
Maryland Heights
Collinsville
Wentzville
Glencoe
Chesterfield
Farmington
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St. Louis flight routes
Alternative routes for Ontario to St. Louis
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Complete your trip
Complete your trip to St. Louis by adding a car rental and/or hotel reservation to your travel itinerary.
Search flights from Ontario to St. Louis by cabin class
Find flights from Ontario to St. Louis, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Ontario and St. Louis flights
Browse other Ontario and St. Louis flight options. Last updated on August 1, 2026.
Other flights from Ontario
Browse through other flights departing from Ontario. Flights are based on user searches made on Cheapflights and were last updated on August 1, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Other flights to St. Louis
Explore flights to St. Louis departing from other origins. Flights are based on user searches made on Cheapflights and were last updated on August 1, 2026.
Top 5 airlines flying from Ontario to St. Louis
Discover the top 5 airlines that operate flights from Ontario to St. Louis. 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 August 1, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$105 | Average$254 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$165 | Average$420 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$292 | Average$536 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$292 | Average$399 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$316 | Average$517 | FlexibilityNo cancel fee | On-time63% |