$160+ Cheap flights from Ontario to St. Louis (STL)
This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 11/10. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — STL
Oct 29 — Nov 51
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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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 September 29, 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 September 29, 2026.
This Mytrip deal was found by Cheapflights users on 9/24. 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.
Wed 10/287:15 am -
2 stops11h 25m
Wed 11/46:44 pm -
2 stops19h 36m
Deal found 9/24![Multiple Airlines logo]()
$388
This Kiwi.com deal was found by Cheapflights users on 9/28. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/306:30 am -
1 stop17h 46m
Mon 11/26:44 pm -
2 stops23h 36m
Deal found 9/28![Multiple Airlines logo]()
$397
This Kiwi.com deal was found by Cheapflights users on 9/24. 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 11/126:30 am -
1 stop17h 46m
Mon 11/166:44 pm -
2 stops23h 36m
Deal found 9/24![Multiple Airlines logo]()
$406
This Kiwi.com deal was found by Cheapflights users on 9/25. 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.
Tue 10/279:20 am -
2 stops33h 20m
Sat 11/74:26 pm -
1 stop20h 14m
Deal found 9/25![Multiple Airlines logo]()
$415
This Kiwi.com deal was found by Cheapflights users on 9/27. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/36:30 am -
1 stop18h 42m
Mon 12/712:02 pm -
2 stops25h 58m
Deal found 9/27![Multiple Airlines logo]()
$416
This Mytrip deal was found by Cheapflights users on 9/27. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/1112:20 pm -
3 stops23h 59m
Wed 11/186:44 pm -
2 stops19h 36m
Deal found 9/27![Multiple Airlines logo]()
$421
This Kiwi.com deal was found by Cheapflights users on 9/25. 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 11/236:30 am -
1 stop18h 29m
Thu 11/265:59 pm -
1 stop18h 41m
Deal found 9/25![Multiple Airlines logo]()
$435
This Kiwi.com deal was found by Cheapflights users on 9/24. 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 12/38:00 am -
1 stop17h 12m
Mon 12/712:02 pm -
2 stops35h 05m
Deal found 9/24![Multiple Airlines logo]()
$494
This United Airlines deal was found by Cheapflights users on 9/27. 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 10/276:00 am -
2 stops11h 59m
Tue 11/31:08 pm -
1 stop7h 08m
Deal found 9/27![United Airlines logo]()
$600
This United Airlines deal was found by Cheapflights users on 9/24. 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.
Wed 10/216:05 am -
1 stop10h 55m
Sat 10/317:30 am -
1 stop5h 39m
Deal found 9/24![United Airlines logo]()
$601
This Air Canada deal was found by Cheapflights users on 9/25. 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.
Fri 10/162:50 pm -
1 stop4h 51m
Mon 10/264:05 pm -
1 stop6h 50m
Deal found 9/25![Air Canada logo]()
$616
This United Airlines deal was found by Cheapflights users on 9/27. 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.
Thu 12/243:10 pm -
2 stops9h 28m
Mon 1/46:58 pm -
2 stops19h 12m
Deal found 9/27![United Airlines logo]()
$626
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 September 29, 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 September 29, 2026.
This American Airlines deal was found by Cheapflights users on 9/28. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/2011:09 am -
1 stop10h 23m
Tue 10/277:03 am -
1 stop8h 44m
Deal found 9/28![American Airlines logo]()
$458
This Delta deal was found by Cheapflights users on 9/26. 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 11/245:15 pm -
1 stop17h 05m
Tue 12/16:03 am -
1 stop9h 16m
Deal found 9/26![Delta logo]()
$460
This United Airlines deal was found by Cheapflights users on 9/25. 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.
Mon 11/237:20 am -
2 stops13h 03m
Thu 11/266:00 am -
2 stops10h 57m
Deal found 9/25![United Airlines logo]()
$584
This Air Canada deal was found by Cheapflights users on 9/28. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/207:15 pm -
Nonstop2h 05m
Tue 10/274:05 pm -
Nonstop1h 54m
Deal found 9/28![Air Canada logo]()
$617
This United deal was found by Cheapflights users on 9/25. 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/2510:53 am -
1 stop4h 37m
Sun 11/14:05 pm -
Nonstop1h 54m
Deal found 9/25![Multiple Airlines logo]()
$623
This United Airlines deal was found by Cheapflights users on 9/27. 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.
Thu 12/246:15 am -
1 stop5h 27m
Mon 1/49:35 am -
2 stops8h 52m
Deal found 9/27![United Airlines logo]()
$600
This Air Canada deal was found by Cheapflights users on 9/24. 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.
Fri 10/162:50 pm -
1 stop4h 51m
Mon 10/264:05 pm -
1 stop6h 50m
Deal found 9/24![Air Canada logo]()
$618
This Delta deal was found by Cheapflights users on 9/24. 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.
Sun 11/87:55 am -
1 stop8h 44m
Sun 11/156:40 am -
1 stop5h 50m
Deal found 9/24![Delta logo]()
$624
This United deal was found by Cheapflights users on 9/25. 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/167:00 am -
1 stop6h 13m
Tue 10/202:40 pm -
Nonstop1h 54m
Deal found 9/25![Multiple Airlines logo]()
$634
This United Airlines deal was found by Cheapflights users on 9/28. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/146:00 am -
1 stop5h 44m
Tue 11/249:40 am -
2 stops11h 16m
Deal found 9/28![United Airlines logo]()
$600
This United Airlines deal was found by Cheapflights users on 9/27. 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 10/276:00 am -
2 stops11h 59m
Tue 11/31:08 pm -
1 stop7h 08m
Deal found 9/27![United Airlines logo]()
$600
This United deal was found by Cheapflights users on 9/26. 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 12/1110:53 am -
1 stop8h 23m
Mon 12/144:05 pm -
Nonstop2h 00m
Deal found 9/26![Multiple Airlines logo]()
$673
This United Airlines deal was found by Cheapflights users on 9/24. 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.
Wed 10/216:00 am -
3 stops9h 17m
Sat 10/3111:15 am -
2 stops9h 41m
Deal found 9/24![United Airlines logo]()
$601
This United Airlines deal was found by Cheapflights users on 9/24. 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.
Thu 12/33:10 pm -
1 stop8h 05m
Mon 12/76:30 am -
1 stop13h 46m
Deal found 9/24![United Airlines logo]()
$601
This United Airlines deal was found by Cheapflights users on 9/25. 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.
Sun 10/258:35 am -
1 stop4h 35m
Sun 11/18:30 am -
1 stop4h 33m
Deal found 9/25![United Airlines logo]()
$623
This United Airlines deal was found by Cheapflights users on 9/24. 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.
Thu 10/228:50 am -
1 stop4h 23m
Thu 10/299:59 am -
1 stop6h 50m
Deal found 9/24![United Airlines logo]()
$624
This United Airlines deal was found by Cheapflights users on 9/27. 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.
Thu 10/221:00 pm -
1 stop9h 21m
Tue 10/275:00 am -
2 stops11h 57m
Deal found 9/27![United Airlines logo]()
$627
This United Airlines deal was found by Cheapflights users on 9/24. 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.
Fri 10/163:10 pm -
1 stop6h 59m
Mon 10/261:08 pm -
2 stops7h 51m
Deal found 9/24![United Airlines logo]()
$632
This United Airlines deal was found by Cheapflights users on 9/25. 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.
Thu 10/156:05 am -
1 stop10h 55m
Mon 10/191:29 pm -
1 stop7h 06m
Deal found 9/25![United Airlines logo]()
$647
This United Airlines deal was found by Cheapflights users on 9/28. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/128:35 am -
1 stop8h 08m
Mon 11/169:40 am -
1 stop8h 05m
Deal found 9/28![United Airlines logo]()
$670
Last-minute flights from Ontario to St. LouisDiscover last-minute flight deals from Ontario to St. Louis. Data last updated September 29, 2026 and is based on user searches.
Discover last-minute flight deals from Ontario to St. Louis. Data last updated September 29, 2026 and is based on user searches.
This United Airlines deal was found by Cheapflights users on 9/25. 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.
Thu 10/156:05 am -
1 stop10h 55m
Mon 10/191:29 pm -
1 stop7h 06m
Deal found 9/25![United Airlines logo]()
$647
This Air Canada deal was found by Cheapflights users on 9/25. 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.
Fri 10/162:50 pm -
1 stop4h 51m
Mon 10/264:05 pm -
1 stop6h 50m
Deal found 9/25![Air Canada logo]()
$616
This United Airlines deal was found by Cheapflights users on 9/24. 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.
Fri 10/163:10 pm -
1 stop6h 59m
Mon 10/261:08 pm -
2 stops7h 51m
Deal found 9/24![United Airlines logo]()
$632
This Delta deal was found by Cheapflights users on 9/28. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/166:50 am -
2 stops12h 33m
Mon 10/262:25 pm -
2 stops9h 19m
Deal found 9/28![Delta logo]()
$659
This American Airlines deal was found by Cheapflights users on 9/27. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/2011:09 am -
1 stop10h 23m
Tue 10/277:03 am -
1 stop8h 44m
Deal found 9/27![American Airlines logo]()
$458
This American Airlines deal was found by Cheapflights users on 9/27. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/2011:09 am -
1 stop10h 23m
Sat 10/317:03 am -
1 stop8h 44m
Deal found 9/27![American Airlines logo]()
$460
This United Airlines deal was found by Cheapflights users on 9/24. 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.
Wed 10/216:05 am -
1 stop10h 55m
Sat 10/317:30 am -
1 stop5h 39m
Deal found 9/24![United Airlines logo]()
$601
This Kiwi.com deal was found by Cheapflights users on 9/25. 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.
Tue 10/279:20 am -
2 stops33h 20m
Sat 11/74:26 pm -
1 stop20h 14m
Deal found 9/25![Multiple Airlines logo]()
$415
This United Airlines deal was found by Cheapflights users on 9/27. 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 10/273:10 pm -
1 stop7h 42m
Tue 11/37:30 am -
1 stop5h 39m
Deal found 9/27![United Airlines logo]()
$600
This Mytrip deal was found by Cheapflights users on 9/24. 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.
Wed 10/287:15 am -
2 stops11h 25m
Wed 11/46:44 pm -
2 stops19h 36m
Deal found 9/24![Multiple Airlines logo]()
$388
This Kiwi.com deal was found by Cheapflights users on 9/28. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/306:30 am -
1 stop17h 46m
Mon 11/26:44 pm -
2 stops23h 36m
Deal found 9/28![Multiple Airlines logo]()
$397
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 September 29, 2026.
Search for one-way flight options from Ontario to St. Louis. Find affordable one-way fares based on user searches. Data last updated September 29, 2026.
This Kiwi.com deal was found by Cheapflights users on 9/25. 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.
Tue 11/1012:20 pm -
2 stops30h 20m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/25![Multiple Airlines logo]()
$160
This Kiwi.com deal was found by Cheapflights users on 9/28. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/1212:20 pm -
2 stops30h 20m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/28![Multiple Airlines logo]()
$174
This Kiwi.com deal was found by Cheapflights users on 9/24. 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.
Sun 11/89:15 am -
2 stops33h 25m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/24![Multiple Airlines logo]()
$180
This Trip.com deal was found by Cheapflights users on 9/24. 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 10/124:45 pm -
2 stops21h 36m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/24![Multiple Airlines logo]()
$199
This Kiwi.com deal was found by Cheapflights users on 9/25. 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.
Sun 11/226:30 am -
1 stop30h 55m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/25![Multiple Airlines logo]()
$241
This Kiwi.com deal was found by Cheapflights users on 9/28. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/159:15 am -
2 stops33h 25m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/28![Multiple Airlines logo]()
$247
This Kiwi.com deal was found by Cheapflights users on 9/27. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/1112:20 pm -
3 stops47h 59m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/27![Multiple Airlines logo]()
$249
This Kiwi.com deal was found by Cheapflights users on 9/27. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/309:05 am -
2 stops51h 12m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/27![Multiple Airlines logo]()
$251
This Air Canada deal was found by Cheapflights users on 9/28. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/710:05 am -
1 stop6h 21m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/28![Air Canada logo]()
$296
This Kiwi.com deal was found by Cheapflights users on 9/28. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/75:40 pm -
3 stops44h 41m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/28![Multiple Airlines logo]()
$327
This United Airlines deal was found by Cheapflights users on 9/28. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/73:10 pm -
2 stops9h 14m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/28![United Airlines logo]()
$329
Find flight deals from Ontario to St. Louis
Keep the following information in mind while searching for Ontario to St. Louis flight deals. Data was last updated September 29, 2026.
Round-trip from | $388 (Mytrip) |
|---|---|
One-way from | $160 (Kiwi.com) |
Popular in | March |
Cheapest in | January |
Average price | $630 |
Good round-trip deal | $498 or less |
Good one-way deal | $360 or less |
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 7,457,451 searches. Data last updated September 29, 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
TorontoSt. Louis
YYZ Toronto Pearson Intl - STL Lambert-St Louis
YYZSTL
Toronto Pearson Intl
Tue 11/10
12:20 pm-5:40 pm
2 stops30h 20m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$160
TorontoSt. Louis
YYZ Toronto Pearson Intl - STL Lambert-St Louis
YYZSTL
Toronto Pearson Intl
Thu 11/12
6:30 am-11:16 pm
1 stop17h 46m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$235
TorontoSt. Louis
YYZ Toronto Pearson Intl - STL Lambert-St Louis
YYZSTL
Toronto Pearson Intl
Sun 11/22
6:30 am-12:25 pm
1 stop30h 55m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$241
OttawaSt. Louis
YOW Ottawa - STL Lambert-St Louis
YOWSTL
Ottawa
Mon 11/30
9:05 am-11:17 am
2 stops51h 12m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$251
TorontoSt. Louis
YYZ Toronto Pearson Intl - STL Lambert-St Louis
YYZSTL
Toronto Pearson Intl
Tue 11/10
12:44 pm-9:38 pm
1 stop9h 54m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$259
TorontoSt. Louis
YYZ Toronto Pearson Intl - STL Lambert-St Louis
YYZSTL
Toronto Pearson Intl
Wed 1/6
11:45 am-7:27 pm
1 stop8h 42m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$269
TorontoSt. Louis
YYZ Toronto Pearson Intl - STL Lambert-St Louis
YYZSTL
Toronto Pearson Intl
Wed 1/6
7:15 am-4:58 pm
2 stops34h 43m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$303
TorontoSt. Louis
YYZ Toronto Pearson Intl - STL Lambert-St Louis
YYZSTL
Toronto Pearson Intl
Wed 11/11
7:20 am-4:59 pm
2 stops10h 39m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$322
OttawaSt. Louis
YOW Ottawa - STL Lambert-St Louis
YOWSTL
Ottawa
Sat 11/7
5:40 pm-1:21 pm
3 stops44h 41m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$327
OttawaSt. Louis
YOW Ottawa - STL Lambert-St Louis
YOWSTL
Ottawa
Sat 11/7
3:10 pm-11:24 pm
2 stops9h 14m
Lambert-St Louis
Wed 12/31
12:00 am-1:00 am
Nonstop0h 00m
$329
Showing 1-10 of 32 resultsSorted by cheapest first
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.
YYZ-STL
YOW-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
CAON-STL
YYZ-STL
YOW-STL
What is the cheapest month to book a flight from Region of Ontario to St. Louis?
Currently, January is the cheapest month in which you can book a flight from Region of Ontario to St. Louis (average of $418). Flying from Region of Ontario to St. Louis in April is currently the most expensive (average of $610). 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 ON to STL?
Find hourly flight availability from Ontario to St. Louis. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated September 29, 2026.
One of the essential ways to save on airfare from Region of Ontario to St. Louis is to remain as flexible as possible. Flights that are in the afternoon tend to be the most expensive. A flight at noon could potentially save you up to 20% on airfare.
Weekly flight availability from Region of Ontario to St. Louis
Explore weekly flight availability from Ontario to St. Louis. 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 September 29, 2026.
The most flights from CAON to STL are scheduled on a Monday (4 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (4 on average).
How much does it cost to fly round-trip from Region of Ontario to St. Louis?
Airfare is typical for this route at the moment.
Region of Ontario to St. Louis flights typically cost between $350 and $556 in October.The cheapest round-trip price found within the last 5 days was $388 on Multiple Airlines (Oct 28-Nov 4).
How far ahead should I book a flight from Region of Ontario to St. Louis?
Booking 46 days in advance of your planned departure date is, on average, the best time to get cheap flights from Region of Ontario to St. Louis. The general trend is that the closer you book to the departure date, the more expensive your flight will be.
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 locationsFairview Heights
O'Fallon
Fenton
Swansea
Eureka
Wentzville
Maryland Heights
Collinsville
Edwardsville
Glencoe
Chesterfield
Browse thousands of different options on Cheapflights for your next trip
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St. Louis flight routes
Alternative routes for Ontario to St. Louis
See prices for flight routes from nearby airports that may be better suited for you.
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 September 29, 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 September 29, 2026.
Top 2 airlines flying from Ontario to St. Louis
Discover the top 2 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 7,457,451 searches. Data last updated September 29, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$226 | Average$549 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$231 | Average$444 | FlexibilityNo cancel fee | On-time67% |