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$141+ Cheap flights from Idaho Falls to St. Louis (IDA - 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 7/20. Fares are subject to change and may not be available on all flights or dates of travel.
IDA — STL
Jul 8 — Jul 151
Wed 7/8
Wed 7/15
1 adult, Economy
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Cheap flight deals from Idaho Falls to St. Louis

Cheapest flights from Idaho Falls to St. Louis
Explore the most affordable flight options available from Idaho Falls to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 8, 2026.

This United Airlines deal was found by Cheapflights users on 6/7. 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 7/224:14 pm
IDA
-
STL
1 stop6h 43m
United Airlines
Sun 7/265:10 am
STL
-
IDA
1 stop5h 40m
United Airlines
Deal found 6/7$365
This United Airlines deal was found by Cheapflights users on 6/4. 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 7/25:54 pm
IDA
-
STL
1 stop5h 03m
United Airlines
Thu 7/95:10 am
STL
-
IDA
1 stop5h 40m
United Airlines
Deal found 6/4$379
This Kiwi.com deal was found by Cheapflights users on 6/4. 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 7/2010:47 pm
IDA
-
STL
1 stop18h 18m
Multiple Airlines
Thu 7/233:41 pm
STL
-
IDA
2 stops25h 19m
Multiple Airlines
Deal found 6/4$380
This Kiwi.com deal was found by Cheapflights users on 6/4. 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 7/2010:47 pm
IDA
-
STL
1 stop18h 18m
Multiple Airlines
Fri 7/244:57 pm
STL
-
IDA
2 stops40h 58m
Multiple Airlines
Deal found 6/4$392
This United Airlines deal was found by Cheapflights users on 6/4. 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 6/194:10 pm
IDA
-
STL
1 stop6h 47m
United Airlines
Tue 6/235:10 am
STL
-
IDA
1 stop5h 40m
United Airlines
Deal found 6/4$394
This Alaska Airlines deal was found by Cheapflights users on 6/3. 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 9/226:18 am
IDA
-
STL
1 stop7h 03m
Alaska Airlines
Sat 9/263:19 pm
STL
-
IDA
1 stop8h 37m
Alaska Airlines
Deal found 6/3$419
This United Airlines deal was found by Cheapflights users on 6/3. 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 7/215:54 pm
IDA
-
STL
1 stop5h 03m
United Airlines
Thu 7/235:10 am
STL
-
IDA
1 stop5h 40m
United Airlines
Deal found 6/3$474
This Alaska Airlines deal was found by Cheapflights users on 6/8. 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 6/241:43 pm
IDA
-
STL
1 stop9h 16m
Alaska Airlines
Tue 6/302:50 pm
STL
-
IDA
1 stop8h 49m
Alaska Airlines
Deal found 6/8$484
This United Airlines deal was found by Cheapflights users on 6/3. 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 9/224:04 pm
IDA
-
STL
2 stops18h 53m
United Airlines
Sat 9/265:10 am
STL
-
IDA
1 stop5h 43m
United Airlines
Deal found 6/3$488
This United Airlines deal was found by Cheapflights users on 6/7. 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 7/164:14 pm
IDA
-
STL
1 stop6h 43m
United Airlines
Mon 7/205:10 am
STL
-
IDA
1 stop5h 40m
United Airlines
Deal found 6/7$489

Find flight deals from Idaho Falls to St. Louis

Discover tips and strategies to find the most affordable flight options for your journey from Idaho Falls (IDA) to St. Louis (STL). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated June 8, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$365
(United Airlines)

One-way from

$141
(Kiwi.com)

Popular in

March

Cheapest in

September

Average price

$632
Provider with most accurate pricing for Idaho Falls Fanning Field-Lambert-St Louis flight deals.
Search Deals
Provider most trusted by Cheapflights users for Idaho Falls Fanning Field-Lambert-St Louis flights.
Search Deals
From Idaho Falls Fanning Field to Lambert-St Louis
Search Deals
One-way flight from Idaho Falls Fanning Field to Lambert-St Louis
Search Deals
Highest demand for flights based on searches. 9% potential increase in price ($56 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($16 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in June 2026
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Idaho Falls 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 June 8, 2026.
Use the filters below to find and compare flights from Idaho Falls to St. Louis that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip
Quickest round-trip

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Wed 7/22

4:14 pm-11:57 pm

1 stop6h 43m

Lambert-St Louis

Sun 7/26

5:10 am-9:50 am

1 stop5h 40m

$365

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Tue 9/22

6:18 am-2:21 pm

1 stop7h 03m

Lambert-St Louis

Sat 9/26

3:19 pm-10:56 pm

1 stop8h 37m

$419

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Tue 9/22

4:04 pm-11:57 am

2 stops18h 53m

Lambert-St Louis

Sat 9/26

5:10 am-9:53 am

1 stop5h 43m

$488

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Thu 7/16

4:14 pm-11:57 pm

1 stop6h 43m

Lambert-St Louis

Mon 7/20

5:10 am-9:50 am

1 stop5h 40m

$489

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Sat 8/29

2:25 pm-8:46 pm

1 stop5h 21m

Lambert-St Louis

Tue 9/1

7:00 am-9:18 pm

2 stops15h 18m

$494

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Sat 8/29

6:18 am-5:10 pm

2 stops9h 52m

Lambert-St Louis

Tue 9/1

3:04 pm-10:56 pm

1 stop8h 52m

$516

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Tue 7/21

4:14 pm-4:37 pm

1 stop23h 23m

Lambert-St Louis

Fri 7/24

7:56 pm-3:37 pm

1 stop20h 41m

$529

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Mon 7/27

4:14 pm-4:37 pm

1 stop23h 23m

Lambert-St Louis

Fri 7/31

5:37 pm-1:06 pm

1 stop20h 29m

$529

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Sat 7/4

12:30 pm-9:26 pm

1 stop7h 56m

Lambert-St Louis

Sat 7/11

5:10 am-9:50 am

1 stop5h 40m

$546
Cheapest one-way

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Thu 8/20

4:04 pm-11:40 pm

1 stop6h 36m

$160

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/7

Showing 1-10 of 18 resultsSorted by cheapest first
1
2

Compare providers for flights from Idaho Falls to St. Louis

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Idaho Falls to St. Louis in June.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Idaho Falls-St. Louis flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Idaho Falls-St. Louis flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Idaho Falls-St. Louis flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Idaho Falls-St. Louis flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Idaho Falls-St. Louis flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Idaho Falls to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Idaho Falls with our price prediction graph.
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 Falls to St. Louis

What is the cheapest month to book a flight from Idaho Falls to St. Louis?

Currently, September is the cheapest month in which you can book a flight from Idaho Falls to St. Louis (average of $430). Flying from Idaho Falls to St. Louis in March is currently the most expensive (average of $738). 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 Falls to St. Louis?

Reviews of airlines servicing St. Louis

Get insights into the airlines that provide service to St. Louis. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to St. Louis. Reviews last updated June 8, 2026.
Read reviews from past customers who have flown Delta,United Airlines, andAmerican Airlines from Idaho Falls to St. Louis. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
7.9
Good
8,396 reviews

Overall

7.9

Boarding

8.1

Entertainment

7.8

Comfort

7.8

Crew

8.5

Food

7.2

Reviews

1 / 20
10.0
Excellent

Anonymous,May 2026

SEA - KOA

The snacks were not very good, not everyone was very friendly and professional
Delta
7.9
Good
8,396 reviews
Delta
7.9
Good
8,396 reviews

Overall

7.9

Boarding

8.1

Entertainment

7.8

Comfort

7.8

Crew

8.5

Food

7.2

Reviews

1 / 20
10.0
Excellent

Anonymous,May 2026

SEA - KOA

The snacks were not very good, not everyone was very friendly and professional
United Airlines
7.4
Good
9,781 reviews
Delta
7.9
Good
8,396 reviews

Overall

7.9

Boarding

8.1

Entertainment

7.8

Comfort

7.8

Crew

8.5

Food

7.2

Reviews

1 / 20
10.0
Excellent

Anonymous,May 2026

SEA - KOA

The snacks were not very good, not everyone was very friendly and professional
American Airlines
7.1
Good
11,640 reviews
Delta
7.9
Good
8,396 reviews

Overall

7.9

Boarding

8.1

Entertainment

7.8

Comfort

7.8

Crew

8.5

Food

7.2

Reviews

1 / 20
10.0
Excellent

Anonymous,May 2026

SEA - KOA

The snacks were not very good, not everyone was very friendly and professional

Related info for your journey

Find useful and relevant information for your journey from Idaho Falls to St. Louis. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • How long is the flight from Idaho Falls to St. Louis?

    A quick flight from Idaho Falls to St. Louis can take about 6h 43m. United Airlines provides one of the quickest options available for as low as $365. The distance from Idaho Falls to St. Louis is about 1171 mi. This flight may include one or multiple stops.

  • What are the cheapest airlines flying from Idaho Falls to St. Louis round-trip?

    Cheapflights users have booked flights from Idaho Falls to St. Louis round-trip from $185. Other airlines that can offer you cheap pricing are American Airlines, from $350, and United Airlines, from $387. Users have found that Delta is 67% cheaper than the other options available to this destination.

  • Can I find deals for flights from Idaho Falls to St. Louis that include hotel bookings?

    Yes. In addition to deals on Idaho Falls to St. Louis flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Idaho Falls to St. Louis?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Idaho Falls to St. Louis.

  • Can I find deals for business class flights from Idaho Falls to St. Louis?

    Yes. Cheapflights offers flight deals from Idaho Falls to St. Louis by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Idaho Falls to St. Louis?

    Currently, September is the cheapest month in which you can book a flight from Idaho Falls to St. Louis (average of $430). Flying from Idaho Falls to St. Louis in March is currently the most expensive (average of $738). 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.

See more FAQs

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
O'Fallon
Edwardsville
Fenton
Swansea
Fairview Heights
Maryland Heights
Collinsville
Eureka
Wentzville
Glencoe
Chesterfield
Alton
Farmington
Festus

Browse thousands of different options on Cheapflights for your next trip

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Top 3 airlines flying from Idaho Falls to St. Louis

Discover the top 3 airlines that operate flights from Idaho Falls 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 June 8, 2026.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$185Average$558FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$350Average$430FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$387Average$520FlexibilityNo cancel feeOn-time69%

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