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St. Louis

$117+ 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 8/12. Fares are subject to change and may not be available on all flights or dates of travel.
BOI — STL
Aug 7 — Aug 141
Thu 8/7
Thu 8/14
1 adult, Economy
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Cheap 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 August 2, 2025.

Round-trip from

$235
(FlightHub)

One-way from

$117
(FlightHub)

Popular in

January

Cheapest in

April

Average price

$341
From Idaho to Lambert-St Louis
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One-way flight from Idaho to Lambert-St Louis
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Highest demand for flights based on searches. 17% potential increase in price ($93 potential increase over avg. RT price).
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Cheapest flight prices on average. 9% potential price decrease ($37 potential savings vs. average RT price).
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Average for round-trip flights in August 2025
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Find flight deals from Idaho to St. Louis

Cheapest flights from Idaho to St. Louis
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 August 2, 2025.

This FlightHub deal was found by Cheapflights users on 7/31. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/2912:33 pmBOI - STL
1 stop19h 38mFrontier
Sat 9/67:55 pmSTL - BOI
1 stop16h 42mFrontier
Deal found 7/31$235
This FlightHub deal was found by Cheapflights users on 7/31. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/912:03 pmGEG - STL
1 stop19h 04mFrontier
Wed 10/157:52 pmSTL - GEG
1 stop17h 16mFrontier
Deal found 7/31$247
This Alaska Airlines deal was found by Cheapflights users on 7/31. 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 10/61:32 pmGEG - STL
1 stop8h 31mAlaska Airlines
Tue 10/146:33 amSTL - GEG
1 stop8h 04mAlaska Airlines
Deal found 7/31$252
This Delta deal was found by Cheapflights users on 7/30. 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 9/275:40 amGEG - STL
1 stop6h 04mDelta
Tue 9/307:00 pmSTL - GEG
1 stop6h 35mDelta
Deal found 7/30$253
This Delta deal was found by Cheapflights users on 7/31. 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 8/275:45 amBOI - STL
2 stops11h 02mDelta
Sat 9/611:29 amSTL - BOI
2 stops12h 03mDelta
Deal found 7/31$274
This Hawaiian Airlines deal was found by Cheapflights users on 8/1. 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 Hawaiian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/114:34 pmBOI - STL
1 stop6h 25mHawaiian Airlines
Sun 9/146:00 amSTL - BOI
1 stop10h 00mHawaiian Airlines
Deal found 8/1$278
This Alaska Airlines deal was found by Cheapflights users on 7/31. 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 8/2710:00 amBOI - STL
1 stop6h 34mAlaska Airlines
Fri 9/56:30 pmSTL - BOI
1 stop6h 38mAlaska Airlines
Deal found 7/31$279
This Delta deal was found by Cheapflights users on 8/1. 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 9/93:15 pmSUN - STL
1 stop5h 03mDelta
Tue 9/167:40 amSTL - SUN
1 stop7h 57mDelta
Deal found 8/1$291
This Hawaiian Airlines deal was found by Cheapflights users on 7/31. 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 Hawaiian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/306:13 amIDA - STL
1 stop7h 26mHawaiian Airlines
Sat 10/46:33 amSTL - IDA
1 stop10h 05mHawaiian Airlines
Deal found 7/31$298
This American Airlines deal was found by Cheapflights users on 7/31. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/71:12 pmGEG - STL
1 stop8h 42mAmerican Airlines
Thu 10/167:16 amSTL - GEG
1 stop7h 04mAmerican Airlines
Deal found 7/31$320
This Alaska Airlines deal was found by Cheapflights users on 7/31. 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.
Sun 11/25:05 amIDA - STL
1 stop8h 13mAlaska Airlines
Sat 11/87:00 amSTL - IDA
1 stop9h 13mAlaska Airlines
Deal found 7/31$327
This Delta deal was found by Cheapflights users on 7/31. 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 9/306:51 pmIDA - STL
2 stops12h 23mDelta
Sat 10/45:30 pmSTL - IDA
1 stop5h 55mDelta
Deal found 7/31$332

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 August 2, 2025.
Use the filters below to find and compare flights from Idaho to St. Louis that are best for you.

Fly from

Idaho

Fly to

St. Louis

Route

Depart

Return

Price

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Fri 8/29

12:33 pm-9:11 am

1 stop19h 38m

Lambert-St Louis

Sat 9/6

7:55 pm-11:37 am

1 stop16h 42m

$235

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

Thu 10/9

12:03 pm-9:07 am

1 stop19h 04m

Lambert-St Louis

Wed 10/15

7:52 pm-11:08 am

1 stop17h 16m

$247

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

Mon 10/6

1:32 pm-12:03 am

1 stop8h 31m

Lambert-St Louis

Tue 10/14

6:33 am-12:37 pm

1 stop8h 04m

$252

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

Sat 9/27

5:40 am-1:44 pm

1 stop6h 04m

Lambert-St Louis

Tue 9/30

7:00 pm-11:35 pm

1 stop6h 35m

$253

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

Tue 1/6

6:00 am-4:14 pm

1 stop8h 14m

Lambert-St Louis

Sun 1/11

5:57 am-12:59 pm

1 stop9h 02m

$272

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Wed 8/27

5:45 am-5:47 pm

2 stops11h 02m

Lambert-St Louis

Sat 9/6

11:29 am-10:32 pm

2 stops12h 03m

$274

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Thu 9/11

4:34 pm-11:59 pm

1 stop6h 25m

Lambert-St Louis

Sun 9/14

6:00 am-3:00 pm

1 stop10h 00m

$278

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Wed 8/27

9:00 am-5:34 pm

1 stop7h 34m

Lambert-St Louis

Thu 9/4

6:30 pm-12:08 am

1 stop6h 38m

$279

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

Tue 1/20

5:00 am-1:52 pm

1 stop6h 52m

Lambert-St Louis

Mon 2/2

2:55 pm-8:59 pm

1 stop8h 04m

$279

HaileySt. Louis

SUN - STL

SUNSTL

Hailey Sun Valley-Friedman

Tue 9/9

3:15 pm-9:18 pm

1 stop5h 03m

Lambert-St Louis

Tue 9/16

7:40 am-2:37 pm

1 stop7h 57m

$291

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/31

Showing 1-10 of 48 results
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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.
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

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

Currently, August is the cheapest month in which you can book a flight from Idaho to St. Louis (average of $311). Flying from Idaho 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 time of day to fly from ID to STL?

Find hourly flight availability from Idaho 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 August 2, 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Idaho to St. Louis as you normally would.

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 August 2, 2025.
See what other customers who have flown with Alaska Airlines, Southwest, and Delta from Idaho to St. Louis have to say. 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.
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Crew

8.5

Comfort

7.8

Food

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Crew

8.5

Comfort

7.8

Food

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Southwest
8.0
Very good
4,246 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Crew

8.5

Comfort

7.8

Food

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Delta
8.0
Very good
7,983 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Crew

8.5

Comfort

7.8

Food

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
Hawaiian Airlines
7.8
Good
2,611 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Crew

8.5

Comfort

7.8

Food

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.
United Airlines
7.4
Good
8,904 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Crew

8.5

Comfort

7.8

Food

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Jonathan,Jul 2025

SEA - BOS

Fantastic Check-in with easy baggage drop. While it took a while to find out which was the gate, the boarding was a dream, the stewards were simply incredible and the flight fantastic.

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.

  • What airport do you fly into for flights to St. Louis from Idaho?

    Located just 12.7 mi from the city center, Lambert-St Louis (STL) is the airport most travelers will use when flying to St. Louis from Idaho.

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

    To fly one-way, consider booking your trip with Frontier, which is currently one of the cheapest options available, starting at $117. Alaska Airlines flights start at $126 while deals on Delta start at $140 one-way.

  • What are the most popular routes from Idaho to St. Louis?

    When deciding which route to take from Idaho to St. Louis consider Boise Air Term. Gowen Fld - Lambert-St Louis, Idaho Falls Fanning Field - Lambert-St Louis or Spokane - Lambert-St Louis as they are the most popular.

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

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

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

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

    Yes. Cheapflights offers flight deals from Idaho 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 to St. Louis?

    Currently, August is the cheapest month in which you can book a flight from Idaho to St. Louis (average of $311). Flying from Idaho 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

Traveling to a place near St. Louis?

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

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Alternative routes for Idaho to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.
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Top 5 airlines flying from Idaho to St. Louis

Discover the top 5 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 August 2, 2025.
AirlineCheapestAverageFlexibilityOn-time
American AirlinesCheapest$226Average$393FlexibilityNo cancel feeOn-time71%
DeltaCheapest$226Average$365FlexibilityNo cancel feeOn-timeN/A
Alaska AirlinesCheapest$278Average$447FlexibilityNo cancel feeOn-time75%
SouthwestCheapest$286Average$448FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$292Average$649FlexibilityNo cancel feeOn-time69%

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