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 $298. Other airlines that can offer you cheap pricing are Delta, from $325, and United Airlines, from $376. Users have found that Hawaiian Airlines is 45% cheaper than the other options available to this destination.

What are the cheapest airlines to fly from Idaho Falls to St. Louis one-way?

The cheapest airlines for a one-way flight from Idaho Falls to St. Louis are American Airlines ($150), Delta ($155), and United Airlines ($476).

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

Currently, August is the cheapest month in which you can book a flight from Idaho Falls to St. Louis (average of $311). Flying from Idaho Falls to St. Louis in March is currently the most expensive (average of $356). 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 day to fly from Idaho Falls to St. Louis?

Travelers seeking maximum savings on their Idaho Falls to St. Louis flight should consider departing on Friday evenings when fares are most often at their lowest. Thursday mornings flights should be avoided if possible as fares are typically the most expensive at this time.

In terms of precipitation, rainfall in St. Louis ranges from 2.2 - 4.7 inches per month. May is typically the wettest month, when rainfall can reach 4.7 in. February is typically the driest time to visit St. Louis when rainfall is around 2.2 in.

If weather is an important factor for your trip to St. Louis, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 80.6 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 32.0 F).

What is the cheapest day to fly round-trip from Idaho Falls to St. Louis?

Sunday flights are found to be more expensive to fly from Idaho Falls to St. Louis. This shouldn’t discourage you from searching, as you can still find great deals by being flexible with your options. Use our search form to find deals on tickets to St. Louis.

What is the cheapest month to fly from Idaho Falls to St. Louis?

Our data shows that February tends to be the cheapest month to fly to St. Louis from Idaho Falls. Users have commonly found prices around $544 for the month, but tickets can be as low as $323. Due to multiple factors, prepare for potentially higher prices in January.

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.

$150+ Flights from Idaho Falls to St. Louis

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Cheap flight deals from Idaho Falls to St. Louis

Round-trip from	$298 (Hawaiian Airlines)
One-way from	$150 (American Airlines)
Popular in	January
Cheapest in	February
Average price	$713

From Idaho Falls Fanning Field to Lambert-St Louis

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One-way flight from Idaho Falls Fanning Field to Lambert-St Louis

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Highest demand for flights based on searches. 8% potential increase in price ($49 potential increase over avg. RT price).

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Cheapest flight prices on average. 5% potential price decrease ($31 potential savings vs. average RT price).

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Average for round-trip flights in July 2025

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Find 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 July 29, 2025.

Tue 9/306:13 amIDA - STL

1 stop7h 26mHawaiian Airlines

Sat 10/43:57 pmSTL - IDA

1 stop7h 41mHawaiian Airlines

Deal found 7/29

$298

Wed 8/2711:20 amIDA - STL

1 stop5h 27mDelta

Thu 9/47:35 amSTL - IDA

1 stop7h 44mDelta

Deal found 7/26

$325

Wed 8/205:56 pmIDA - STL

1 stop4h 57mUnited Airlines

Sat 8/236:35 amSTL - IDA

2 stops9h 36mUnited Airlines

Deal found 7/26

$376

Sat 8/21:47 pmIDA - STL

1 stop8h 10mAmerican Airlines

Sat 8/97:23 amSTL - IDA

1 stop6h 37mAmerican Airlines

Deal found 7/27

$716

Best flights from Idaho Falls to St. Louis
Discover carefully curated flight deals from Idaho Falls to St. Louis that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated July 29, 2025.

Tue 9/306:13 amIDA - STL

1 stop7h 26mHawaiian Airlines

Sat 10/43:57 pmSTL - IDA

1 stop7h 41mHawaiian Airlines

Deal found 7/29

$298

Wed 8/2711:20 amIDA - STL

1 stop5h 27mDelta

Thu 9/47:35 amSTL - IDA

1 stop7h 44mDelta

Deal found 7/26

$325

Wed 8/205:56 pmIDA - STL

1 stop4h 57mUnited Airlines

Sat 8/236:35 amSTL - IDA

2 stops9h 36mUnited Airlines

Deal found 7/26

$376

Last-minute flights from Idaho Falls to St. Louis
Discover last-minute flight deals from Idaho Falls to St. Louis. Data last updated July 29, 2025 and is based on user searches.

Sat 8/21:47 pmIDA - STL

1 stop8h 10mAmerican Airlines

Sat 8/97:23 amSTL - IDA

1 stop6h 37mAmerican Airlines

Deal found 7/27

$716

Wed 8/205:56 pmIDA - STL

1 stop4h 57mUnited Airlines

Sat 8/236:35 amSTL - IDA

2 stops9h 36mUnited Airlines

Deal found 7/26

$376

Wed 8/2711:20 amIDA - STL

1 stop5h 27mDelta

Thu 9/47:35 amSTL - IDA

1 stop7h 44mDelta

Deal found 7/26

$325

One-way flights from Idaho Falls to St. Louis
Search for one-way flight options from Idaho Falls to St. Louis. Find affordable one-way fares based on user searches. Data last updated July 29, 2025.

Wed 9/241:35 pmIDA - STL

1 stop8h 15mAmerican Airlines

Deal found 7/29

$150

Wed 9/246:51 pmIDA - STL

2 stops12h 23mDelta

Deal found 7/29

$155

Tue 8/55:00 amIDA - STL

1 stop6h 46mUnited Airlines

Deal found 7/28

$476

Cheapflights Fare Finder

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

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Tue 9/30

6:13 am-2:39 pm

1 stop7h 26m

Lambert-St Louis

Sat 10/4

3:57 pm-10:38 pm

1 stop7h 41m

$298

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Wed 8/27

11:20 am-5:47 pm

1 stop5h 27m

Lambert-St Louis

Thu 9/4

7:35 am-2:19 pm

1 stop7h 44m

$325

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Wed 8/20

5:56 pm-11:53 pm

1 stop4h 57m

Lambert-St Louis

Sat 8/23

6:35 am-3:11 pm

2 stops9h 36m

$376

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Wed 9/24

1:35 pm-10:50 pm

1 stop8h 15m

$150

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Wed 9/24

6:51 pm-8:14 am

2 stops12h 23m

$155

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Tue 8/5

5:00 am-12:46 pm

1 stop6h 46m

$476

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/29

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 time of day to fly from IDA to STL?

Unlike at noon, when flights are generally more expensive, you can save up to 23% on flights from Idaho Falls to St. Louis by exploring options for tickets in the afternoon.

Reviews of airlines servicing St. Louis

Read reviews from past customers who have flown Delta, Hawaiian Airlines, and United 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

8.0

Very good

7,979 reviews

Reviews

1 / 20

10.0

Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

Delta

8.0

Very good

7,979 reviews

Delta

8.0

Very good

7,979 reviews

Reviews

1 / 20

10.0

Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

Hawaiian Airlines

7.8

Good

2,605 reviews

Delta

8.0

Very good

7,979 reviews

Reviews

1 / 20

10.0

Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

United Airlines

7.4

Good

8,896 reviews

Delta

8.0

Very good

7,979 reviews

Reviews

1 / 20

10.0

Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

American Airlines

7.2

Good

10,000 reviews

Delta

8.0

Very good

7,979 reviews

Reviews

1 / 20

10.0

Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

Related info for your journey

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 $298. Other airlines that can offer you cheap pricing are Delta, from $325, and United Airlines, from $376. Users have found that Hawaiian Airlines is 45% cheaper than the other options available to this destination.
What are the cheapest airlines to fly from Idaho Falls to St. Louis one-way?
The cheapest airlines for a one-way flight from Idaho Falls to St. Louis are American Airlines ($150), Delta ($155), and United Airlines ($476).
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, August is the cheapest month in which you can book a flight from Idaho Falls to St. Louis (average of $311). Flying from Idaho Falls to St. Louis in March is currently the most expensive (average of $356). 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

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Collinsville

Eureka

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Glencoe

Alton

Chesterfield

Festus

Farmington

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Top airline flying from Idaho Falls to St. Louis

Airline	Cheapest	Average	Flexibility	On-time
American Airlines	Cheapest$324	Average$384	FlexibilityNo cancel fee	On-time71%

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$150+ 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 9/24. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from Idaho Falls to St. Louis with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Cheap flight deals from Idaho Falls to St. Louis

Round-trip from

One-way from

Popular in

Cheapest in

Average price

Find flight deals from Idaho Falls to St. Louis

Cheapest flights from Idaho Falls to St. LouisExplore 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 July 29, 2025.

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 July 29, 2025.

Cheapflights Fare Finder

Use the filters below to find and compare flights from Idaho Falls to St. Louis that are best for you.

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.

Cheapflights Insights

Everything you need to know about your flight from Idaho Falls to St. Louis

What is the cheapest time of day to fly from IDA to STL?

Find hourly flight availability from Idaho Falls 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 29, 2025.

Reviews of airlines servicing St. Louis

Read reviews from past customers who have flown Delta, Hawaiian Airlines, and United 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.

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.

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

What are the cheapest airlines to fly from Idaho Falls to St. Louis one-way?

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

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

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

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

Traveling to a place near St. Louis?

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.

Alternative routes for Idaho Falls to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.

Top airline flying from Idaho Falls to St. Louis

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Book with Flexibility

Travel Smart

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 July 29, 2025.