$104+ Cheap flights from Illinois to St. Louis (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 9/21. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — STL
Aug 21 — Aug 281
Round-trip
1 adult, Economy
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Find cheap flights from Illinois 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 Illinois to St. Louis
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Cheapest flights from Illinois to St. LouisExplore the most affordable flight options available from Illinois to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 22, 2026.
Explore the most affordable flight options available from Illinois to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 22, 2026.
This Frontier deal was found by Cheapflights users on 7/19. 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 8/611:06 am
MDW
- STL
1 stop6h 31m
Frontier
Fri 8/74:57 pm
STL
- MDW
1 stop5h 06m
Frontier
Deal found 7/19![Frontier logo]()
$300
This Frontier deal was found by Cheapflights users on 7/17. 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.
Fri 7/315:13 pm
ORD
- STL
1 stop6h 46m
Frontier
Mon 8/37:10 pm
STL
- ORD
1 stop10h 27m
Frontier
Deal found 7/17![Frontier logo]()
$300
This Kiwi.com deal was found by Cheapflights users on 7/17. 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 8/105:13 pm
ORD
- STL
2 stops21h 43m
Frontier
Wed 8/124:57 pm
STL
- ORD
1 stop15h 05m
Frontier
Deal found 7/17![Frontier logo]()
$302
This Kiwi.com deal was found by Cheapflights users on 7/17. 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 9/111:02 pm
MDW
- STL
2 stops20h 38m
Frontier
Tue 9/1510:35 am
STL
- MDW
1 stop24h 23m
Frontier
Deal found 7/17![Frontier logo]()
$303
This American Airlines deal was found by Cheapflights users on 7/19. 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.
Thu 9/248:57 am
ORD
- STL
Nonstop1h 23m
American Airlines
Thu 9/245:18 pm
STL
- ORD
Nonstop1h 55m
American Airlines
Deal found 7/19![American Airlines logo]()
$303
This Kiwi.com deal was found by Cheapflights users on 7/18. 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 8/259:20 am
ORD
- STL
1 stop7h 11m
Frontier
Fri 8/286:17 pm
STL
- ORD
2 stops18h 33m
Frontier
Deal found 7/18![Frontier logo]()
$304
This Kiwi.com deal was found by Cheapflights users on 7/17. 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 8/111:50 pm
ORD
- STL
1 stop19h 07m
Frontier
Thu 8/138:08 pm
STL
- ORD
2 stops11h 54m
Frontier
Deal found 7/17![Frontier logo]()
$305
This Southwest deal was found by Cheapflights users on 7/17. 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.
Sat 8/159:55 am
MDW
- STL
2 stops6h 45m
Southwest
Sat 8/227:50 am
STL
- MDW
2 stops5h 30m
Southwest
Deal found 7/17![Southwest logo]()
$307
This Delta deal was found by Cheapflights users on 7/17. 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.
Wed 8/261:59 pm
ORD
- STL
1 stop6h 43m
Delta
Thu 8/2710:33 am
STL
- ORD
1 stop5h 44m
Delta
Deal found 7/17![Delta logo]()
$307
This Frontier deal was found by Cheapflights users on 7/19. 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.
Sun 8/26:05 am
MDW
- STL
1 stop11h 32m
Frontier
Wed 8/54:57 pm
STL
- MDW
1 stop5h 06m
Frontier
Deal found 7/19![Frontier logo]()
$308
This Kiwi.com deal was found by Cheapflights users on 7/17. 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 8/161:50 pm
ORD
- STL
1 stop19h 07m
Frontier
Sun 8/236:17 pm
STL
- ORD
2 stops25h 48m
Frontier
Deal found 7/17![Frontier logo]()
$309
This Southwest deal was found by Cheapflights users on 7/20. 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 7/239:35 pm
MDW
- STL
Nonstop1h 20m
Southwest
Tue 8/256:30 am
STL
- MDW
Nonstop1h 05m
Southwest
Deal found 7/20![Southwest logo]()
$310
Best flights from Illinois to St. LouisDiscover carefully curated flight deals from Illinois to St. Louis that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated July 22, 2026.
Discover carefully curated flight deals from Illinois to St. Louis that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated July 22, 2026.
This Delta deal was found by Cheapflights users on 7/17. 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.
Wed 9/308:55 am
ORD
- STL
1 stop4h 11m
Delta
Fri 10/26:40 am
STL
- ORD
1 stop3h 57m
Delta
Deal found 7/17![Delta logo]()
$326
This American Airlines deal was found by Cheapflights users on 7/21. 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 8/116:49 am
ORD
- STL
1 stop6h 13m
American Airlines
Tue 8/118:07 pm
STL
- ORD
Nonstop1h 33m
American Airlines
Deal found 7/21![American Airlines logo]()
$327
This United Airlines deal was found by Cheapflights users on 7/21. 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 8/2110:29 am
ORD
- STL
Nonstop1h 33m
United Airlines
Sun 8/236:54 pm
STL
- ORD
Nonstop1h 36m
United Airlines
Deal found 7/21![United Airlines logo]()
$337
This Southwest deal was found by Cheapflights users on 7/20. 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.
Fri 8/2812:30 pm
MDW
- STL
1 stop5h 25m
Southwest
Sun 8/3012:55 pm
STL
- MDW
Nonstop1h 10m
Southwest
Deal found 7/20![Southwest logo]()
$347
This Kiwi.com deal was found by Cheapflights users on 7/21. 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 8/117:29 am
ORD
- STL
1 stop10h 36m
Frontier
Tue 8/118:08 pm
STL
- ORD
2 stops11h 54m
Frontier
Deal found 7/21![Frontier logo]()
$414
This Delta deal was found by Cheapflights users on 7/20. 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.
Sat 9/54:52 pm
MDW
- STL
1 stop5h 11m
Delta
Sun 9/610:33 am
STL
- MDW
1 stop6h 26m
Delta
Deal found 7/20![Delta logo]()
$327
This American Airlines deal was found by Cheapflights users on 7/21. 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.
Fri 9/2511:05 pm
ORD
- STL
Nonstop1h 22m
American Airlines
Sun 9/2711:01 am
STL
- ORD
Nonstop1h 28m
American Airlines
Deal found 7/21![American Airlines logo]()
$337
This United Airlines deal was found by Cheapflights users on 7/17. 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 8/238:40 am
ORD
- STL
Nonstop1h 32m
United Airlines
Sun 8/235:30 pm
STL
- ORD
Nonstop1h 31m
United Airlines
Deal found 7/17![United Airlines logo]()
$337
This Southwest deal was found by Cheapflights users on 7/17. 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.
Fri 8/143:10 pm
MDW
- STL
Nonstop1h 10m
Southwest
Fri 8/218:35 am
STL
- MDW
1 stop3h 45m
Southwest
Deal found 7/17![Southwest logo]()
$358
This Delta deal was found by Cheapflights users on 7/17. 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.
Sat 9/56:59 am
ORD
- STL
2 stops9h 45m
Delta
Sun 9/66:30 am
STL
- ORD
1 stop4h 12m
Delta
Deal found 7/17![Delta logo]()
$332
This KAYAK deal was found by Cheapflights users on 7/21. 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 9/145:20 am
ORD
- STL
1 stop7h 43m
American Airlines
Thu 9/175:00 am
STL
- ORD
Nonstop1h 29m
American Airlines
Deal found 7/21![American Airlines logo]()
$374
This Delta deal was found by Cheapflights users on 7/17. 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 9/159:29 am
MDW
- STL
2 stops7h 18m
Delta
Wed 9/161:55 pm
STL
- MDW
1 stop4h 38m
Delta
Deal found 7/17![Delta logo]()
$361
This Southwest deal was found by Cheapflights users on 7/19. 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 8/63:20 pm
MDW
- STL
1 stop3h 50m
Southwest
Sun 8/912:55 pm
STL
- MDW
Nonstop1h 10m
Southwest
Deal found 7/19![Southwest logo]()
$409
This Delta deal was found by Cheapflights users on 7/19. 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 8/259:24 am
MDW
- STL
1 stop3h 50m
Delta
Wed 8/266:20 am
STL
- MDW
2 stops6h 19m
Delta
Deal found 7/19![Delta logo]()
$361
This KAYAK deal was found by Cheapflights users on 7/20. 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 8/247:00 am
ORD
- STL
Nonstop1h 24m
American Airlines
Wed 8/265:42 am
STL
- ORD
1 stop5h 29m
American Airlines
Deal found 7/20![American Airlines logo]()
$403
This Delta deal was found by Cheapflights users on 7/18. 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 8/149:24 am
MDW
- STL
1 stop3h 50m
Delta
Sun 8/166:30 am
STL
- MDW
1 stop6h 09m
Delta
Deal found 7/18![Delta logo]()
$368
This Southwest deal was found by Cheapflights users on 7/17. 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.
Fri 7/318:55 am
MDW
- STL
1 stop4h 55m
Southwest
Sun 8/21:30 pm
STL
- MDW
Nonstop1h 05m
Southwest
Deal found 7/17![Southwest logo]()
$449
This KAYAK deal was found by Cheapflights users on 7/21. 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 9/141:55 pm
ORD
- STL
1 stop6h 40m
Delta
Thu 9/176:40 am
STL
- ORD
1 stop3h 57m
Delta
Deal found 7/21![Delta logo]()
$369
This Southwest deal was found by Cheapflights users on 7/18. 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 8/511:10 am
MDW
- STL
1 stop5h 15m
Southwest
Fri 8/78:50 pm
STL
- MDW
Nonstop1h 05m
Southwest
Deal found 7/18![Southwest logo]()
$449
This Delta deal was found by Cheapflights users on 7/19. 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.
Mon 9/141:55 pm
ORD
- STL
1 stop6h 40m
Delta
Tue 9/1511:21 am
STL
- ORD
2 stops9h 09m
Delta
Deal found 7/19![Delta logo]()
$393
This American Airlines deal was found by Cheapflights users on 7/21. 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.
Thu 8/202:51 pm
SPI
- STL
1 stop9h 23m
American Airlines
Thu 8/276:00 am
STL
- SPI
1 stop42h 12m
American Airlines
Deal found 7/21![American Airlines logo]()
$551
This Delta deal was found by Cheapflights users on 7/20. 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.
Thu 8/271:25 pm
MDW
- STL
1 stop4h 13m
Delta
Sun 8/306:20 am
STL
- MDW
2 stops6h 19m
Delta
Deal found 7/20![Delta logo]()
$422
This Delta deal was found by Cheapflights users on 7/17. 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.
Sat 10/37:05 am
ORD
- STL
2 stops9h 42m
Delta
Mon 10/56:40 am
STL
- ORD
1 stop3h 57m
Delta
Deal found 7/17![Delta logo]()
$432
This American Airlines deal was found by Cheapflights users on 7/19. 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.
Mon 8/32:55 pm
SPI
- STL
1 stop21h 56m
American Airlines
Fri 8/79:32 am
STL
- SPI
1 stop28h 45m
American Airlines
Deal found 7/19![American Airlines logo]()
$925
Last-minute flights from Illinois to St. LouisDiscover last-minute flight deals from Illinois to St. Louis. Data last updated July 22, 2026 and is based on user searches.
Discover last-minute flight deals from Illinois to St. Louis. Data last updated July 22, 2026 and is based on user searches.
This Southwest deal was found by Cheapflights users on 7/20. 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 7/239:35 pm
MDW
- STL
Nonstop1h 20m
Southwest
Tue 8/256:30 am
STL
- MDW
Nonstop1h 05m
Southwest
Deal found 7/20![Southwest logo]()
$310
This United Airlines deal was found by Cheapflights users on 7/20. 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 7/2312:55 pm
ORD
- STL
Nonstop1h 28m
United Airlines
Tue 8/257:25 am
STL
- ORD
Nonstop1h 36m
United Airlines
Deal found 7/20![United Airlines logo]()
$310
This Frontier deal was found by Cheapflights users on 7/17. 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.
Fri 7/315:13 pm
ORD
- STL
1 stop6h 46m
Frontier
Mon 8/37:10 pm
STL
- ORD
1 stop10h 27m
Frontier
Deal found 7/17![Frontier logo]()
$300
This Frontier deal was found by Cheapflights users on 7/19. 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.
Sun 8/26:05 am
MDW
- STL
1 stop11h 32m
Frontier
Wed 8/54:57 pm
STL
- MDW
1 stop5h 06m
Frontier
Deal found 7/19![Frontier logo]()
$308
This Frontier deal was found by Cheapflights users on 7/19. 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 8/611:06 am
MDW
- STL
1 stop6h 31m
Frontier
Fri 8/74:57 pm
STL
- MDW
1 stop5h 06m
Frontier
Deal found 7/19![Frontier logo]()
$300
This Southwest deal was found by Cheapflights users on 7/20. 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.
Sat 8/89:55 am
MDW
- STL
2 stops6h 45m
Southwest
Sat 8/296:45 am
STL
- MDW
2 stops6h 20m
Southwest
Deal found 7/20![Southwest logo]()
$311
This Kiwi.com deal was found by Cheapflights users on 7/17. 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 8/105:13 pm
ORD
- STL
2 stops21h 43m
Frontier
Wed 8/124:57 pm
STL
- ORD
1 stop15h 05m
Frontier
Deal found 7/17![Frontier logo]()
$302
This Kiwi.com deal was found by Cheapflights users on 7/17. 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 8/111:50 pm
ORD
- STL
1 stop19h 07m
Frontier
Thu 8/138:08 pm
STL
- ORD
2 stops11h 54m
Frontier
Deal found 7/17![Frontier logo]()
$305
This Southwest deal was found by Cheapflights users on 7/17. 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.
Sat 8/159:55 am
MDW
- STL
2 stops6h 45m
Southwest
Sat 8/227:50 am
STL
- MDW
2 stops5h 30m
Southwest
Deal found 7/17![Southwest logo]()
$307
This Kiwi.com deal was found by Cheapflights users on 7/17. 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 8/161:50 pm
ORD
- STL
1 stop19h 07m
Frontier
Sun 8/236:17 pm
STL
- ORD
2 stops25h 48m
Frontier
Deal found 7/17![Frontier logo]()
$309
This Kiwi.com deal was found by Cheapflights users on 7/18. 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 8/259:20 am
ORD
- STL
1 stop7h 11m
Frontier
Fri 8/286:17 pm
STL
- ORD
2 stops18h 33m
Frontier
Deal found 7/18![Frontier logo]()
$304
This Delta deal was found by Cheapflights users on 7/17. 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.
Wed 8/261:59 pm
ORD
- STL
1 stop6h 43m
Delta
Thu 8/2710:33 am
STL
- ORD
1 stop5h 44m
Delta
Deal found 7/17![Delta logo]()
$307
One-way flights from Illinois to St. LouisSearch for one-way flight options from Illinois to St. Louis. Find affordable one-way fares based on user searches. Data last updated July 22, 2026.
Search for one-way flight options from Illinois to St. Louis. Find affordable one-way fares based on user searches. Data last updated July 22, 2026.
This Kiwi.com deal was found by Cheapflights users on 7/21. 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 9/212:03 pm
ORD
- STL
1 stop19h 37m
Frontier
Deal found 7/21![Frontier logo]()
$104
This Frontier deal was found by Cheapflights users on 7/21. 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.
Tue 8/189:20 am
ORD
- STL
1 stop6h 56m
Frontier
Deal found 7/21![Frontier logo]()
$110
This Delta deal was found by Cheapflights users on 7/21. 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.
Sat 10/179:29 am
MDW
- STL
1 stop5h 56m
Delta
Deal found 7/21![Delta logo]()
$113
This Kiwi.com deal was found by Cheapflights users on 7/21. 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 9/192:46 pm
ORD
- STL
2 stops18h 54m
Frontier
Deal found 7/21![Frontier logo]()
$113
This Kiwi.com deal was found by Cheapflights users on 7/21. 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 8/3011:50 am
MDW
- STL
1 stop5h 32m
Frontier
Deal found 7/21![Frontier logo]()
$114
This Kiwi.com deal was found by Cheapflights users on 7/21. 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 10/211:02 pm
MDW
- STL
2 stops20h 38m
Frontier
Deal found 7/21![Frontier logo]()
$117
This Kiwi.com deal was found by Cheapflights users on 7/21. 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 9/222:46 pm
ORD
- STL
2 stops18h 54m
Frontier
Deal found 7/21![Frontier logo]()
$118
This Kiwi.com deal was found by Cheapflights users on 7/21. 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 9/66:05 am
MDW
- STL
1 stop11h 17m
Frontier
Deal found 7/21![Frontier logo]()
$119
This Kiwi.com deal was found by Cheapflights users on 7/21. 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 8/146:05 am
MDW
- STL
1 stop26h 52m
Frontier
Deal found 7/21![Frontier logo]()
$120
This Kiwi.com deal was found by Cheapflights users on 7/21. 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 8/307:05 am
ORD
- STL
1 stop10h 17m
Frontier
Deal found 7/21![Frontier logo]()
$120
This Kiwi.com deal was found by Cheapflights users on 7/21. 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 9/206:30 am
ORD
- STL
1 stop27h 10m
Frontier
Deal found 7/21![Frontier logo]()
$123
This Frontier deal was found by Cheapflights users on 7/20. 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.
Sun 8/167:29 am
ORD
- STL
1 stop10h 46m
Frontier
Deal found 7/20![Frontier logo]()
$130
Find flight deals from Illinois to St. Louis
Keep the following information in mind while searching for Illinois to St. Louis flight deals. Data was last updated July 22, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $300 (Frontier) |
One-way from | $104 (Kiwi.com) |
Popular in | April |
Cheapest in | December |
Average price | $449 |
Good round-trip deal | $61 or less |
Good one-way deal | $179 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Illinois 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 July 22, 2026.
Use the filters below to find and compare flights from Illinois to St. Louis that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
ChicagoSt. Louis
ORD - STL
ORDSTL
Chicago O'Hare Intl
Wed 9/30
8:55 am-1:06 pm
1 stop4h 11m
Lambert-St Louis
Fri 10/2
6:40 am-10:37 am
1 stop3h 57m
$326
ChicagoSt. Louis
ORD - STL
ORDSTL
Chicago O'Hare Intl
Tue 8/11
6:49 am-1:02 pm
1 stop6h 13m
Lambert-St Louis
Tue 8/11
8:07 pm-9:40 pm
Nonstop1h 33m
$327
ChicagoSt. Louis
MDW - STL
MDWSTL
Chicago Midway
Sat 9/5
4:52 pm-10:03 pm
1 stop5h 11m
Lambert-St Louis
Sun 9/6
10:33 am-4:59 pm
1 stop6h 26m
$327
ChicagoSt. Louis
ORD - STL
ORDSTL
Chicago O'Hare Intl
Sat 9/5
6:59 am-4:44 pm
2 stops9h 45m
Lambert-St Louis
Sun 9/6
6:30 am-10:42 am
1 stop4h 12m
$332
ChicagoSt. Louis
ORD - STL
ORDSTL
Chicago O'Hare Intl
Fri 8/21
10:29 am-12:02 pm
Nonstop1h 33m
Lambert-St Louis
Sun 8/23
6:54 pm-8:30 pm
Nonstop1h 36m
$337
Quickest round-trip
ChicagoSt. Louis
ORD - STL
ORDSTL
Chicago O'Hare Intl
Fri 9/25
11:05 pm-12:27 am
Nonstop1h 22m
Lambert-St Louis
Sun 9/27
11:01 am-12:29 pm
Nonstop1h 28m
$337
ChicagoSt. Louis
ORD - STL
ORDSTL
Chicago O'Hare Intl
Sun 8/23
8:40 am-10:12 am
Nonstop1h 32m
Lambert-St Louis
Sun 8/23
5:30 pm-7:01 pm
Nonstop1h 31m
$337
ChicagoSt. Louis
MDW - STL
MDWSTL
Chicago Midway
Fri 8/28
12:30 pm-5:55 pm
1 stop5h 25m
Lambert-St Louis
Sun 8/30
12:55 pm-2:05 pm
Nonstop1h 10m
$347
ChicagoSt. Louis
MDW - STL
MDWSTL
Chicago Midway
Fri 8/14
3:10 pm-4:20 pm
Nonstop1h 10m
Lambert-St Louis
Fri 8/21
8:35 am-12:20 pm
1 stop3h 45m
$358
ChicagoSt. Louis
MDW - STL
MDWSTL
Chicago Midway
Tue 9/15
9:29 am-4:47 pm
2 stops7h 18m
Lambert-St Louis
Wed 9/16
1:55 pm-6:33 pm
1 stop4h 38m
$361
Showing 1-10 of 46 resultsSorted by cheapest first
Best time to book a flight from Illinois to St. Louis
Have a flexible travel schedule? Discover the best time to fly to St. Louis from Illinois with our price prediction graph.
MDW-STL
ORD-STL
SPI-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 Illinois to St. Louis
USIL-STL
MDW-STL
ORD-STL
SPI-STL
What is the cheapest month to book a flight from Illinois to St. Louis?
Currently, December is the cheapest month in which you can book a flight from Illinois to St. Louis (average of $214). Flying from Illinois to St. Louis in April is currently the most expensive (average of $601). 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 IL to STL?
Find hourly flight availability from Illinois 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 July 22, 2026.
It’s typically best to fly out from Illinois to St. Louis at noon. Doing so could potentially save you 33% on the flight price compared to flying in the evening, which is usually more expensive.
Weekly flight availability from Illinois to St. Louis
Explore weekly flight availability from Illinois 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 July 22, 2026.
The most flights from USIL to STL are scheduled on a Tuesday (72 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (34 on average).
How much does it cost to fly round-trip from Illinois to St. Louis?
How far ahead should I book a flight from Illinois to St. Louis?
The price you pay for your flight from Illinois to St. Louis may vary depending on when you book. For the best chance of a lower fare, look to book 74 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.
What is the cheapest day to fly from Illinois to St. Louis?
Use this chart to determine the cheapest time to fly round-trip from Illinois to St. Louis. Price data was last updated on July 18, 2026.
Travelers seeking maximum savings on their Illinois to St. Louis flight should consider departing on Saturday afternoons when fares are most often at their lowest. Sunday evenings flights should be avoided if possible as fares are typically the most expensive at this time.
Related info for your journey
Find useful and relevant information for your journey from Illinois 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
Browse thousands of different options on Cheapflights for your next trip
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Alternative routes for Illinois to St. Louis
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Complete your trip
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Illinois and St. Louis flights
Browse other Illinois and St. Louis flight options. Last updated on July 22, 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 July 22, 2026.
Illinois to St. Louis flights
Consider these flights traveling from Illinois to St. Louis.
Top 4 airlines flying from Illinois to St. Louis
Discover the top 4 airlines that operate flights from Illinois 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 July 22, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$77 | Average$476 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$151 | Average$366 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$157 | Average$486 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$165 | Average$213 | FlexibilityNo cancel fee | On-timeN/A |