$137+ Cheap flights from Idaho 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 9/28. Fares are subject to change and may not be available on all flights or dates of travel.
BOI — STL
Aug 27 — Sep 31
Round-trip
1 adult, Economy
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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
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Cheapest flights from Idaho to St. LouisExplore the most affordable flight options available from Idaho to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 28, 2026.
Explore the most affordable flight options available from Idaho to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 28, 2026.
This Expedia deal was found by Cheapflights users on 7/23. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/1712:59 pm
BOI
- STL
1 stop5h 16m
Multiple Airlines
Tue 9/226:29 am
STL
- BOI
1 stop7h 06m
Multiple Airlines
Deal found 7/23![Multiple Airlines logo]()
$304
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.
Fri 9/182:50 pm
BOI
- STL
1 stop19h 42m
Frontier
Sun 9/2012:27 pm
STL
- BOI
1 stop26h 28m
Frontier
Deal found 7/27![Frontier logo]()
$315
This CheapOair deal was found by Cheapflights users on 7/26. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/233:52 pm
BOI
- STL
1 stop8h 25m
Frontier
Sun 10/255:19 pm
STL
- BOI
1 stop22h 38m
Frontier
Deal found 7/26![Frontier logo]()
$316
This Delta 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/226:56 pm
IDA
- STL
1 stop4h 34m
Delta
Wed 12/27:10 am
STL
- IDA
1 stop6h 05m
Delta
Deal found 7/28![Delta logo]()
$329
This Kiwi.com deal was found by Cheapflights users on 7/23. 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 9/1512:59 pm
BOI
- STL
2 stops19h 41m
Frontier
Sat 9/1912:46 pm
STL
- BOI
1 stop27h 11m
Frontier
Deal found 7/23![Frontier logo]()
$333
This Delta 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/226:56 pm
IDA
- STL
2 stops12h 57m
Delta
Sat 12/57:10 am
STL
- IDA
1 stop6h 05m
Delta
Deal found 7/28![Delta logo]()
$334
This Delta deal was found by Cheapflights users on 7/26. 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 8/257:00 pm
IDA
- STL
2 stops12h 08m
Delta
Tue 9/112:52 pm
STL
- IDA
2 stops10h 40m
Delta
Deal found 7/26![Delta logo]()
$339
This Kiwi.com deal was found by Cheapflights users on 7/23. 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 9/173:52 pm
BOI
- STL
1 stop18h 59m
Frontier
Tue 9/2210:35 am
STL
- BOI
2 stops50h 29m
Frontier
Deal found 7/23![Frontier logo]()
$344
This Delta 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/166:56 pm
IDA
- STL
1 stop4h 34m
Delta
Thu 12/242:15 pm
STL
- IDA
1 stop4h 59m
Delta
Deal found 7/28![Delta logo]()
$354
This Kiwi.com deal was found by Cheapflights users on 7/23. 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 10/115:00 pm
GEG
- STL
1 stop30h 17m
Multiple Airlines
Thu 10/156:41 pm
STL
- GEG
2 stops24h 46m
Multiple Airlines
Deal found 7/23![Multiple Airlines logo]()
$358
This Trip.com deal was found by Cheapflights users on 7/25. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/88:30 am
GEG
- STL
1 stop6h 40m
Alaska Airlines
Tue 9/156:29 am
STL
- GEG
1 stop7h 08m
Alaska Airlines
Deal found 7/25![Alaska Airlines logo]()
$362
This Alaska Airlines deal was found by Cheapflights users on 7/23. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/96:00 am
BOI
- STL
1 stop10h 10m
Alaska Airlines
Tue 9/156:29 am
STL
- BOI
1 stop7h 06m
Alaska Airlines
Deal found 7/23![Alaska Airlines logo]()
$363
Best flights from Idaho to St. LouisDiscover carefully curated flight deals from Idaho to St. Louis that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated July 28, 2026.
Discover carefully curated flight deals from Idaho to St. Louis that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated July 28, 2026.
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.
Fri 9/182:50 pm
BOI
- STL
1 stop19h 42m
Frontier
Sun 9/2012:27 pm
STL
- BOI
1 stop26h 28m
Frontier
Deal found 7/27![Frontier logo]()
$315
This Delta deal was found by Cheapflights users on 7/26. 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 8/256:00 am
IDA
- STL
1 stop6h 38m
Delta
Tue 9/111:00 am
STL
- IDA
2 stops12h 32m
Delta
Deal found 7/26![Delta logo]()
$334
This Alaska Airlines deal was found by Cheapflights users on 7/23. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/272:06 pm
BOI
- STL
1 stop8h 53m
Alaska Airlines
Wed 10/287:02 am
STL
- BOI
1 stop8h 09m
Alaska Airlines
Deal found 7/23![Alaska Airlines logo]()
$363
This Southwest deal was found by Cheapflights users on 7/23. 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 9/152:20 pm
BOI
- STL
1 stop7h 30m
Southwest
Sat 9/194:20 pm
STL
- BOI
1 stop6h 45m
Southwest
Deal found 7/23![Southwest logo]()
$363
This United Airlines deal was found by Cheapflights users on 7/25. 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.
Tue 9/152:41 pm
BOI
- STL
1 stop4h 57m
United Airlines
Sat 9/194:40 pm
STL
- BOI
1 stop7h 00m
United Airlines
Deal found 7/25![United Airlines logo]()
$369
This American Airlines deal was found by Cheapflights users on 7/24. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/91:50 pm
BOI
- STL
1 stop8h 53m
American Airlines
Tue 9/153:34 pm
STL
- BOI
1 stop7h 53m
American Airlines
Deal found 7/24![American Airlines logo]()
$369
This CheapOair deal was found by Cheapflights users on 7/23. 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.
Fri 10/233:52 pm
BOI
- STL
1 stop8h 25m
Frontier
Sun 10/255:19 pm
STL
- BOI
1 stop22h 38m
Frontier
Deal found 7/23![Frontier logo]()
$329
This Alaska Airlines deal was found by Cheapflights users on 7/23. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/217:24 pm
GEG
- STL
1 stop19h 46m
Alaska Airlines
Thu 9/246:08 pm
STL
- GEG
1 stop7h 03m
Alaska Airlines
Deal found 7/23![Alaska Airlines logo]()
$363
This Southwest deal was found by Cheapflights users on 7/26. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/26:00 am
BOI
- STL
1 stop8h 05m
Southwest
Tue 9/85:25 pm
STL
- BOI
1 stop6h 05m
Southwest
Deal found 7/26![Southwest logo]()
$369
This American Airlines deal was found by Cheapflights users on 7/25. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/2412:44 pm
GEG
- STL
1 stop8h 58m
American Airlines
Mon 8/313:32 pm
STL
- GEG
1 stop7h 10m
American Airlines
Deal found 7/25![American Airlines logo]()
$369
This Southwest deal was found by Cheapflights users on 7/25. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/223:25 pm
BOI
- STL
1 stop5h 55m
Southwest
Sat 8/294:20 pm
STL
- BOI
1 stop6h 40m
Southwest
Deal found 7/25![Southwest logo]()
$369
This Alaska Airlines deal was found by Cheapflights users on 7/25. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/96:00 am
BOI
- STL
1 stop10h 10m
Alaska Airlines
Tue 9/156:29 am
STL
- BOI
1 stop7h 06m
Alaska Airlines
Deal found 7/25![Alaska Airlines logo]()
$369
This Delta 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/236:00 am
IDA
- STL
2 stops9h 34m
Delta
Wed 12/26:20 am
STL
- IDA
2 stops12h 56m
Delta
Deal found 7/28![Delta logo]()
$407
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.
Sat 10/242:28 pm
IDA
- STL
1 stop5h 08m
United Airlines
Wed 10/287:30 am
STL
- IDA
2 stops9h 08m
United Airlines
Deal found 7/27![United Airlines logo]()
$424
This Alaska Airlines deal was found by Cheapflights users on 7/24. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/317:20 am
GEG
- STL
1 stop6h 24m
Alaska Airlines
Wed 11/47:00 am
STL
- GEG
1 stop7h 45m
Alaska Airlines
Deal found 7/24![Alaska Airlines logo]()
$369
This Southwest deal was found by Cheapflights users on 7/24. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/256:15 am
GEG
- STL
1 stop9h 35m
Southwest
Sat 8/2911:50 am
STL
- GEG
1 stop8h 30m
Southwest
Deal found 7/24![Southwest logo]()
$369
This Delta 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/145:14 pm
GEG
- STL
1 stop5h 30m
Delta
Fri 9/182:25 pm
STL
- GEG
1 stop5h 49m
Delta
Deal found 7/27![Delta logo]()
$410
This United Airlines 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/12:38 pm
SUN
- STL
1 stop4h 58m
United Airlines
Mon 10/54:39 pm
STL
- SUN
1 stop5h 46m
United Airlines
Deal found 7/28![United Airlines logo]()
$445
This Alaska Airlines deal was found by Cheapflights users on 7/25. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/257:03 am
GEG
- STL
1 stop9h 35m
Alaska Airlines
Sat 8/296:08 pm
STL
- GEG
1 stop7h 03m
Alaska Airlines
Deal found 7/25![Alaska Airlines logo]()
$369
This American Airlines deal was found by Cheapflights users on 7/24. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/314:30 pm
JAC
- STL
1 stop6h 12m
American Airlines
Tue 9/16:00 am
STL
- JAC
1 stop7h 15m
American Airlines
Deal found 7/24![American Airlines logo]()
$460
This Delta 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 12/186:56 pm
IDA
- STL
1 stop4h 34m
Delta
Thu 12/241:30 pm
STL
- IDA
2 stops9h 49m
Delta
Deal found 7/27![Delta logo]()
$434
This Alaska 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/246:09 am
IDA
- STL
1 stop8h 35m
Alaska Airlines
Wed 10/287:02 am
STL
- IDA
1 stop9h 18m
Alaska Airlines
Deal found 7/27![Alaska Airlines logo]()
$379
This United Airlines deal was found by Cheapflights users on 7/23. 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 9/25:00 am
GEG
- STL
2 stops10h 06m
United Airlines
Wed 9/910:53 am
STL
- GEG
2 stops12h 21m
United Airlines
Deal found 7/23![United Airlines logo]()
$464
This Delta deal was found by Cheapflights users on 7/26. 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.
Mon 9/217:30 pm
GEG
- STL
2 stops13h 01m
Delta
Fri 9/255:47 pm
STL
- GEG
1 stop7h 07m
Delta
Deal found 7/26![Delta logo]()
$457
This Delta deal was found by Cheapflights users on 7/26. 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.
Mon 9/217:30 pm
GEG
- STL
2 stops13h 01m
Delta
Thu 9/246:55 pm
STL
- GEG
1 stop6h 34m
Delta
Deal found 7/26![Delta logo]()
$457
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.
Thu 8/279:28 am
JAC
- STL
1 stop7h 31m
United Airlines
Mon 8/319:00 am
STL
- JAC
1 stop4h 49m
United Airlines
Deal found 7/27![United Airlines logo]()
$519
This United Airlines deal was found by Cheapflights users on 7/26. 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 Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/34:25 pm
JAC
- STL
1 stop6h 06m
United Airlines
Sun 9/612:30 pm
STL
- JAC
1 stop9h 50m
United Airlines
Deal found 7/26![United Airlines logo]()
$519
This Travelocity 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 Travelocity is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/110:28 am
SUN
- STL
2 stops12h 15m
Alaska Airlines
Mon 10/510:12 am
STL
- SUN
2 stops25h 54m
Alaska Airlines
Deal found 7/28![Alaska Airlines logo]()
$630
This Delta 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/811:44 am
PIH
- STL
2 stops11h 10m
Delta
Tue 10/132:38 pm
STL
- PIH
2 stops8h 10m
Delta
Deal found 7/27![Delta logo]()
$708
This United Airlines deal was found by Cheapflights users on 7/24. 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.
Mon 8/317:00 am
JAC
- STL
2 stops7h 38m
United Airlines
Tue 9/110:53 am
STL
- JAC
2 stops7h 56m
United Airlines
Deal found 7/24![United Airlines logo]()
$778
Last-minute flights from Idaho to St. LouisDiscover last-minute flight deals from Idaho to St. Louis. Data last updated July 28, 2026 and is based on user searches.
Discover last-minute flight deals from Idaho to St. Louis. Data last updated July 28, 2026 and is based on user searches.
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.
Thu 7/301:24 pm
BOI
- STL
1 stop4h 59m
Frontier
Wed 8/58:08 pm
STL
- BOI
1 stop17h 21m
Frontier
Deal found 7/27![Frontier logo]()
$390
This American Airlines deal was found by Cheapflights users on 7/25. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/183:19 pm
BOI
- STL
1 stop7h 55m
American Airlines
Thu 8/279:32 am
STL
- BOI
1 stop5h 57m
American Airlines
Deal found 7/25![American Airlines logo]()
$369
This Southwest deal was found by Cheapflights users on 7/25. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/2212:55 pm
BOI
- STL
2 stops8h 25m
Southwest
Sat 8/292:25 pm
STL
- BOI
2 stops8h 35m
Southwest
Deal found 7/25![Southwest logo]()
$379
This American Airlines deal was found by Cheapflights users on 7/26. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/2412:44 pm
GEG
- STL
1 stop8h 58m
American Airlines
Sat 8/298:00 am
STL
- GEG
1 stop8h 09m
American Airlines
Deal found 7/26![American Airlines logo]()
$369
This Southwest deal was found by Cheapflights users on 7/23. 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 8/246:00 am
GEG
- STL
2 stops10h 25m
Southwest
Sat 8/297:10 am
STL
- GEG
2 stops9h 25m
Southwest
Deal found 7/23![Southwest logo]()
$398
This Delta deal was found by Cheapflights users on 7/26. 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 8/257:00 pm
IDA
- STL
1 stop4h 41m
Delta
Tue 9/15:00 pm
STL
- IDA
1 stop6h 32m
Delta
Deal found 7/26![Delta logo]()
$329
This American Airlines deal was found by Cheapflights users on 7/26. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/252:20 pm
IDA
- STL
1 stop8h 22m
American Airlines
Tue 9/16:00 am
STL
- IDA
1 stop8h 09m
American Airlines
Deal found 7/26![American Airlines logo]()
$354
This Southwest deal was found by Cheapflights users on 7/23. 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 8/256:15 am
GEG
- STL
1 stop9h 35m
Southwest
Sat 8/2911:50 am
STL
- GEG
1 stop8h 30m
Southwest
Deal found 7/23![Southwest logo]()
$363
This American Airlines deal was found by Cheapflights users on 7/26. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/255:20 am
GEG
- STL
2 stops10h 45m
American Airlines
Sat 8/295:00 am
STL
- GEG
2 stops11h 09m
American Airlines
Deal found 7/26![American Airlines logo]()
$380
This Delta deal was found by Cheapflights users on 7/26. 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.
Wed 8/267:54 pm
GEG
- STL
2 stops10h 43m
Delta
Wed 9/211:13 am
STL
- GEG
2 stops12h 03m
Delta
Deal found 7/26![Delta logo]()
$384
This Southwest deal was found by Cheapflights users on 7/25. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/2710:55 am
GEG
- STL
2 stops9h 10m
Southwest
Tue 9/12:45 pm
STL
- GEG
2 stops9h 40m
Southwest
Deal found 7/25![Southwest logo]()
$406
This Priceline deal was found by Cheapflights users on 7/23. 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.
Sun 8/3012:24 pm
BOI
- STL
1 stop5h 49m
Multiple Airlines
Fri 9/46:08 pm
STL
- BOI
1 stop6h 47m
Multiple Airlines
Deal found 7/23![Multiple Airlines logo]()
$398
One-way flights from Idaho to St. LouisSearch for one-way flight options from Idaho to St. Louis. Find affordable one-way fares based on user searches. Data last updated July 28, 2026.
Search for one-way flight options from Idaho to St. Louis. Find affordable one-way fares based on user searches. Data last updated July 28, 2026.
This CheapOair deal was found by Cheapflights users on 7/25. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/282:50 pm
BOI
- STL
1 stop19h 42m
Frontier
Deal found 7/25![Frontier logo]()
$137
This Priceline deal was found by Cheapflights users on 7/26. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/3012:24 pm
BOI
- STL
1 stop5h 49m
Frontier
Deal found 7/26![Frontier logo]()
$159
This Kiwi.com deal was found by Cheapflights users on 7/24. 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 9/132:50 pm
BOI
- STL
2 stops27h 25m
Frontier
Deal found 7/24![Frontier logo]()
$164
This Expedia deal was found by Cheapflights users on 7/26. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/2312:24 pm
BOI
- STL
1 stop5h 49m
Frontier
Deal found 7/26![Frontier logo]()
$172
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/161:24 pm
BOI
- STL
1 stop4h 59m
Frontier
Deal found 7/28![Frontier logo]()
$179
This Southwest deal was found by Cheapflights users on 7/23. 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 8/152:25 pm
BOI
- STL
1 stop6h 10m
Southwest
Deal found 7/23![Southwest logo]()
$182
This American Airlines deal was found by Cheapflights users on 7/23. 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 9/112:44 pm
GEG
- STL
1 stop8h 58m
American Airlines
Deal found 7/23![American Airlines logo]()
$182
This CheapOair deal was found by Cheapflights users on 7/25. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/272:50 pm
BOI
- STL
1 stop20h 01m
Frontier
Deal found 7/25![Frontier logo]()
$184
This Priceline deal was found by Cheapflights users on 7/26. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/242:17 pm
BOI
- STL
1 stop8h 42m
Alaska Airlines
Deal found 7/26![Alaska Airlines logo]()
$185
This United Airlines deal was found by Cheapflights users on 7/24. 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 11/265:00 am
BOI
- STL
2 stops9h 43m
United Airlines
Deal found 7/24![United Airlines logo]()
$190
This Expedia deal was found by Cheapflights users on 7/24. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/61:24 pm
BOI
- STL
1 stop4h 59m
Frontier
Deal found 7/24![Frontier logo]()
$195
This Kiwi.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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/169:14 pm
GEG
- STL
2 stops20h 09m
Multiple Airlines
Deal found 7/28![Multiple Airlines logo]()
$205
Find flight deals from Idaho to St. Louis
Keep the following information in mind while searching for Idaho to St. Louis flight deals. Data was last updated July 28, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $304 (Expedia) |
One-way from | $137 (CheapOair) |
Popular in | March |
Cheapest in | October |
Average price | $492 |
Cheapflights Fare Finder
Customize your flight search to find flights from Idaho 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 28, 2026.
Use the filters below to find and compare flights from Idaho to St. Louis that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
BoiseSt. Louis
BOI - STL
BOISTL
Boise Air Term. Gowen Fld
Fri 9/18
2:50 pm-11:32 am
1 stop19h 42m
Lambert-St Louis
Sun 9/20
12:27 pm-1:55 pm
1 stop26h 28m
$315
BoiseSt. Louis
BOI - STL
BOISTL
Boise Air Term. Gowen Fld
Fri 10/23
3:52 pm-1:17 am
1 stop8h 25m
Lambert-St Louis
Sun 10/25
5:19 pm-2:57 pm
1 stop22h 38m
$329
Idaho FallsSt. Louis
IDA - STL
IDASTL
Idaho Falls Fanning Field
Tue 8/25
6:00 am-1:38 pm
1 stop6h 38m
Lambert-St Louis
Tue 9/1
11:00 am-10:32 pm
2 stops12h 32m
$334
BoiseSt. Louis
BOI - STL
BOISTL
Boise Air Term. Gowen Fld
Tue 10/27
2:06 pm-11:59 pm
1 stop8h 53m
Lambert-St Louis
Wed 10/28
7:02 am-2:11 pm
1 stop8h 09m
$363
BoiseSt. Louis
BOI - STL
BOISTL
Boise Air Term. Gowen Fld
Tue 9/15
2:20 pm-10:50 pm
1 stop7h 30m
Lambert-St Louis
Sat 9/19
4:20 pm-10:05 pm
1 stop6h 45m
$363
SpokaneSt. Louis
GEG - STL
GEGSTL
Spokane
Mon 9/21
7:24 pm-5:10 pm
1 stop19h 46m
Lambert-St Louis
Thu 9/24
6:08 pm-11:11 pm
1 stop7h 03m
$363
BoiseSt. Louis
BOI - STL
BOISTL
Boise Air Term. Gowen Fld
Tue 9/15
2:41 pm-8:38 pm
1 stop4h 57m
Lambert-St Louis
Sat 9/19
4:40 pm-10:40 pm
1 stop7h 00m
$369
BoiseSt. Louis
BOI - STL
BOISTL
Boise Air Term. Gowen Fld
Wed 9/9
1:50 pm-11:43 pm
1 stop8h 53m
Lambert-St Louis
Tue 9/15
3:34 pm-10:27 pm
1 stop7h 53m
$369
BoiseSt. Louis
BOI - STL
BOISTL
Boise Air Term. Gowen Fld
Wed 9/2
6:00 am-3:05 pm
1 stop8h 05m
Lambert-St Louis
Tue 9/8
5:25 pm-10:30 pm
1 stop6h 05m
$369
SpokaneSt. Louis
GEG - STL
GEGSTL
Spokane
Mon 8/24
12:44 pm-11:42 pm
1 stop8h 58m
Lambert-St Louis
Mon 8/31
3:32 pm-8:42 pm
1 stop7h 10m
$369
Showing 1-10 of 54 resultsSorted by cheapest first
Best time to book a flight from Idaho to St. Louis
Have a flexible travel schedule? Discover the best time to fly to St. Louis from Idaho with our price prediction graph.
BOI-STL
GEG-STL
IDA-STL
JAC-STL
SUN-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 Idaho to St. Louis
USID-STL
BOI-STL
GEG-STL
IDA-STL
JAC-STL
What is the cheapest month to book a flight from Idaho to St. Louis?
Currently, September is the cheapest month in which you can book a flight from Idaho to St. Louis (average of $434). Flying from Idaho to St. Louis in February is currently the most expensive (average of $837). 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 Idaho to St. Louis?
Airfare is below average for this route at the moment.
Idaho to St. Louis flights typically cost between $414 and $676 in September.The cheapest round-trip price found within the last 5 days was $304 on Multiple Airlines (Sep 17-Sep 22).
Related info for your journey
Find useful and relevant information for your journey from Idaho 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
Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.
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Alternative routes for Idaho 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.
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Idaho and St. Louis flights
Browse other Idaho and St. Louis flight options. Last updated on July 28, 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 28, 2026.
Idaho to St. Louis flights
Consider these flights traveling from Idaho to St. Louis.
Top 3 airlines flying from Idaho to St. Louis
Discover the top 3 airlines that operate flights from Idaho 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 28, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$185 | Average$501 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$283 | Average$498 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$347 | Average$502 | FlexibilityNo cancel fee | On-time63% |