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St. Louis

$139+ 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 8/18. Fares are subject to change and may not be available on all flights or dates of travel.
BOI — STL
juin 20 — juin 271
ven. 6/20
ven. 6/27
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 juin 15, 2025.

Round-trip from

$277
(American Airlines)

One-way from

$139
(Delta)

Popular in

January

Cheapest in

April

Average price

$392
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. 18% potential increase in price ($96 potential increase over avg. RT price).
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Cheapest flight prices on average. 9% potential price decrease ($36 potential savings vs. average RT price).
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Average for round-trip flights in June 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 juin 15, 2025.

This American Airlines deal was found by Cheapflights users on 6/14. 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.
jeu. 8/73:10 pmGEG - STL
1 stop7h 06mAmerican Airlines
mar. 8/125:15 amSTL - GEG
1 stop8h 24mAmerican Airlines
Deal found 6/14$277
This United Airlines deal was found by Cheapflights users on 6/13. 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.
mer. 11/55:00 amBOI - STL
1 stop6h 39mUnited Airlines
mar. 11/119:00 amSTL - BOI
1 stop5h 25mUnited Airlines
Deal found 6/13$279
This Hawaiian Airlines deal was found by Cheapflights users on 6/14. 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.
ven. 9/196:35 amBOI - STL
1 stop7h 04mHawaiian Airlines
sam. 9/273:35 pmSTL - BOI
1 stop8h 05mHawaiian Airlines
Deal found 6/14$286
This American Airlines deal was found by Cheapflights users on 6/14. 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.
ven. 9/261:17 pmBOI - STL
1 stop7h 36mAmerican Airlines
dim. 9/287:23 amSTL - BOI
1 stop6h 09mAmerican Airlines
Deal found 6/14$287
This Southwest deal was found by Cheapflights users on 6/13. 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.
mer. 11/512:05 pmBOI - STL
2 stops8h 30mSouthwest
mar. 11/1110:25 amSTL - BOI
2 stops7h 45mSouthwest
Deal found 6/13$289
This Delta deal was found by Cheapflights users on 6/13. 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.
jeu. 8/711:09 pmGEG - STL
1 stop7h 17mDelta
mar. 8/127:35 amSTL - GEG
2 stops9h 10mDelta
Deal found 6/13$291
This Delta deal was found by Cheapflights users on 6/13. 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.
mer. 11/57:30 amBOI - STL
2 stops9h 27mDelta
mar. 11/117:30 amSTL - BOI
2 stops13h 46mDelta
Deal found 6/13$306
This Alaska Airlines deal was found by Cheapflights users on 6/14. 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.
sam. 8/308:46 pmBOI - STL
1 stop16h 53mAlaska Airlines
dim. 8/316:30 pmSTL - BOI
2 stops13h 50mAlaska Airlines
Deal found 6/14$340
This Southwest deal was found by Cheapflights users on 6/14. 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.
ven. 10/174:25 pmGEG - STL
1 stop5h 30mSouthwest
dim. 10/1910:30 pmSTL - GEG
1 stop12h 45mSouthwest
Deal found 6/14$342
This American Airlines deal was found by Cheapflights users on 6/14. 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.
mer. 9/33:25 pmJAC - STL
1 stop17h 01mAmerican Airlines
dim. 9/75:19 amSTL - JAC
1 stop6h 11mAmerican Airlines
Deal found 6/14$352
This FlightHub deal was found by Cheapflights users on 6/13. 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.
jeu. 7/1011:58 amGEG - STL
1 stop19h 13mFrontier
lun. 7/147:29 pmSTL - GEG
1 stop17h 37mFrontier
Deal found 6/13$361
This Delta deal was found by Cheapflights users on 6/14. 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.
sam. 8/307:30 amJAC - STL
1 stop4h 59mDelta
sam. 8/305:30 pmSTL - JAC
1 stop4h 59mDelta
Deal found 6/14$371

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 juin 15, 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

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

jeu. 8/7

3:10 pm-12:16 am

1 stop7h 06m

Lambert-St Louis

mar. 8/12

5:15 am-11:39 am

1 stop8h 24m

$277

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

mer. 11/5

5:00 am-12:39 pm

1 stop6h 39m

Lambert-St Louis

mar. 11/11

9:00 am-1:25 pm

1 stop5h 25m

$279

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

ven. 9/19

6:35 am-2:39 pm

1 stop7h 04m

Lambert-St Louis

sam. 9/27

3:35 pm-10:40 pm

1 stop8h 05m

$286

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

ven. 9/26

1:17 pm-9:53 pm

1 stop7h 36m

Lambert-St Louis

dim. 9/28

7:23 am-12:32 pm

1 stop6h 09m

$287

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

mer. 11/5

12:05 pm-9:35 pm

2 stops8h 30m

Lambert-St Louis

mar. 11/11

10:25 am-5:10 pm

2 stops7h 45m

$289

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

jeu. 8/7

11:09 pm-8:26 am

1 stop7h 17m

Lambert-St Louis

mar. 8/12

7:35 am-2:45 pm

2 stops9h 10m

$291

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

mer. 11/5

7:30 am-5:57 pm

2 stops9h 27m

Lambert-St Louis

mar. 11/11

7:30 am-8:16 pm

2 stops13h 46m

$306

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

sam. 8/30

8:46 pm-2:39 pm

1 stop16h 53m

Lambert-St Louis

dim. 8/31

6:30 pm-7:20 am

2 stops13h 50m

$340

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

ven. 10/17

4:25 pm-11:55 pm

1 stop5h 30m

Lambert-St Louis

dim. 10/19

10:30 pm-9:15 am

1 stop12h 45m

$342

JacksonSt. Louis

JAC - STL

JACSTL

Jackson Hole

mer. 9/3

3:25 pm-9:26 am

1 stop17h 01m

Lambert-St Louis

dim. 9/7

5:19 am-10:30 am

1 stop6h 11m

$352

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/13

Showing 1-10 of 38 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 juin 15, 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.

Rainfall in St. Louis by month

Plan your trip to St. Louis by taking into account the average rainfall totals by month.

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.

Temperature in St. Louis by month

Plan your trip to St. Louis by taking into account the average temperature totals by month.

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).

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 juin 15, 2025.
Peruse reviews from past customers who have flown with Alaska Airlines, Southwest and Delta from Idaho to St. Louis to help guide your decision. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Overall

8.0

Food

7.1

Entertainment

7.1

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Overall

8.0

Food

7.1

Entertainment

7.1

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Southwest
8.0
Very good
4,285 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Overall

8.0

Food

7.1

Entertainment

7.1

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Delta
8.0
Very good
7,961 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Overall

8.0

Food

7.1

Entertainment

7.1

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Hawaiian Airlines
7.8
Good
2,499 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Overall

8.0

Food

7.1

Entertainment

7.1

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
United Airlines
7.4
Good
8,793 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Overall

8.0

Food

7.1

Entertainment

7.1

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

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 Delta, which is currently one of the cheapest options available, starting at $139. American Airlines flights start at $154 while deals on Southwest start at $169 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 Spokane - Lambert-St Louis, Boise Air Term. Gowen Fld - Lambert-St Louis or Idaho Falls Fanning Field - 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 Idaho?

Book flights to Idaho if you plan to visit one of these locations
O'Fallon
Maryland Heights
Fairview Heights
Collinsville
Eureka
St. Peters
Glencoe
Festus
Alton
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 juin 15, 2025.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$208Average$445FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$226Average$406FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$292Average$648FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$326Average$447FlexibilityNo cancel feeOn-time75%
SouthwestCheapest$346Average$458FlexibilityNo cancel feeOn-time63%

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