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$140+ Cheap flights from St. Louis (STL) to Idaho

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 9/4. Fares are subject to change and may not be available on all flights or dates of travel.
STL — BOI
Jun 17 — Jun 241
Tue 6/17
Tue 6/24
1 adult, Economy
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Cheap flight deals from St. Louis to Idaho

Keep the following information in mind while searching for St. Louis to Idaho flight deals. Data was last updated June 12, 2025.

Round-trip from

$254
(Alaska Airlines)

One-way from

$140
(American Airlines)

Popular in

November

Cheapest in

April

Average price

$439
From Lambert-St Louis to Idaho
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One-way flight from Lambert-St Louis to Idaho
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Highest demand for flights based on searches. 8% potential increase in price ($37 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease ($8 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 St. Louis to Idaho

Cheapest flights from St. Louis to Idaho
Explore the most affordable flight options available from St. Louis to Idaho. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 12, 2025.

This Alaska Airlines deal was found by Cheapflights users on 6/10. 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 9/163:35 pmSTL - BOI
1 stop8h 05mAlaska Airlines
Wed 9/246:35 amBOI - STL
1 stop7h 04mAlaska Airlines
Deal found 6/10$254
This Delta deal was found by Cheapflights users on 6/10. 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 9/186:59 pmSTL - BOI
1 stop6h 18mDelta
Thu 9/2511:30 pmBOI - STL
1 stop7h 40mDelta
Deal found 6/10$255
This Southwest deal was found by Cheapflights users on 6/10. 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 9/84:00 pmSTL - BOI
2 stops8h 05mSouthwest
Mon 9/154:30 pmBOI - STL
1 stop6h 25mSouthwest
Deal found 6/10$260
This American Airlines deal was found by Cheapflights users on 6/10. 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.
Thu 8/145:15 amSTL - BOI
1 stop8h 31mAmerican Airlines
Sun 8/175:15 pmBOI - STL
1 stop6h 01mAmerican Airlines
Deal found 6/10$271
This FlightHub deal was found by Cheapflights users on 6/11. 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.
Sat 9/137:52 pmSTL - GEG
1 stop17h 16mFrontier
Sun 9/2112:08 pmGEG - STL
1 stop18h 59mFrontier
Deal found 6/11$276
This Delta deal was found by Cheapflights users on 6/10. 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 8/63:41 pmSTL - GEG
1 stop8h 18mDelta
Tue 8/125:05 pmGEG - STL
1 stop5h 33mDelta
Deal found 6/10$279
This Southwest deal was found by Cheapflights users on 6/10. 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 8/194:35 pmSTL - GEG
2 stops7h 55mSouthwest
Tue 8/266:15 amGEG - STL
1 stop8h 40mSouthwest
Deal found 6/10$284
This Hawaiian Airlines deal was found by Cheapflights users on 6/10. 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.
Sat 9/133:35 pmSTL - BOI
1 stop8h 05mHawaiian Airlines
Sat 9/206:35 amBOI - STL
1 stop7h 04mHawaiian Airlines
Deal found 6/10$286
This American Airlines deal was found by Cheapflights users on 6/11. 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.
Sat 8/167:53 amSTL - GEG
1 stop7h 14mAmerican Airlines
Sat 8/2312:14 pmGEG - STL
1 stop6h 36mAmerican Airlines
Deal found 6/11$307
This Alaska Airlines deal was found by Cheapflights users on 6/10. 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.
Thu 9/116:30 pmSTL - GEG
1 stop7h 29mAlaska Airlines
Sun 9/145:46 pmGEG - STL
1 stop18h 53mAlaska Airlines
Deal found 6/10$332
This American Airlines deal was found by Cheapflights users on 6/11. 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 9/95:55 amSTL - JAC
1 stop10h 33mAmerican Airlines
Wed 9/173:25 pmJAC - STL
1 stop5h 28mAmerican Airlines
Deal found 6/11$343
This United Airlines deal was found by Cheapflights users on 6/9. 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 8/215:15 amSTL - BOI
2 stops9h 15mUnited Airlines
Tue 8/265:00 amBOI - STL
2 stops8h 33mUnited Airlines
Deal found 6/9$345

Cheapflights Fare Finder

Customize your flight search to find flights from St. Louis to Idaho 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 12, 2025.
Use the filters below to find and compare flights from St. Louis to Idaho that are best for you.

Fly from

St. Louis

Fly to

Idaho

Route

Depart

Return

Price

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Mon 9/8

6:30 pm-9:28 am

1 stop15h 58m

Boise Air Term. Gowen Fld

Mon 9/15

4:34 pm-11:59 pm

1 stop6h 25m

$254

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Thu 8/21

6:00 am-12:19 pm

1 stop7h 19m

Boise Air Term. Gowen Fld

Tue 8/26

1:36 pm-11:14 pm

1 stop8h 38m

$255

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Mon 9/8

4:00 pm-11:05 pm

2 stops8h 05m

Boise Air Term. Gowen Fld

Mon 9/15

4:30 pm-11:55 pm

1 stop6h 25m

$260

St. LouisSpokane

STL - GEG

STLGEG

Lambert-St Louis

Wed 8/6

3:41 pm-9:59 pm

1 stop8h 18m

Spokane

Tue 8/12

5:05 pm-12:38 am

1 stop5h 33m

$279

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Thu 8/21

7:11 pm-11:59 pm

1 stop5h 48m

Boise Air Term. Gowen Fld

Tue 8/26

5:45 am-5:47 pm

2 stops11h 02m

$280

St. LouisSpokane

STL - GEG

STLGEG

Lambert-St Louis

Tue 8/19

4:35 pm-10:30 pm

2 stops7h 55m

Spokane

Tue 8/26

6:15 am-4:55 pm

1 stop8h 40m

$284

St. LouisSpokane

STL - GEG

STLGEG

Lambert-St Louis

Sat 8/16

7:53 am-1:07 pm

1 stop7h 14m

Spokane

Sat 8/23

12:14 pm-8:50 pm

1 stop6h 36m

$307

St. LouisJackson

STL - JAC

STLJAC

Lambert-St Louis

Tue 9/9

5:55 am-3:28 pm

1 stop10h 33m

Jackson Hole

Wed 9/17

3:25 pm-9:53 pm

1 stop5h 28m

$343

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Thu 8/21

5:15 am-1:30 pm

2 stops9h 15m

Boise Air Term. Gowen Fld

Tue 8/26

5:00 am-2:33 pm

2 stops8h 33m

$345

St. LouisSpokane

STL - GEG

STLGEG

Lambert-St Louis

Wed 7/9

3:24 pm-9:09 pm

1 stop7h 45m

Spokane

Wed 7/16

9:45 am-6:35 pm

1 stop6h 50m

$370

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/10

Showing 1-10 of 45 results
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Best time to book a flight from St. Louis to Idaho

Have a flexible travel schedule? Discover the best time to fly to Idaho from St. Louis 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 St. Louis to Idaho

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

Currently, October is the cheapest month in which you can book a flight from St. Louis to Idaho (average of $314). Flying from St. Louis to Idaho in June is currently the most expensive (average of $395). 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 STL to ID?

Find hourly flight availability from St. Louis to Idaho. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 12, 2025.

When flying from St. Louis to Idaho, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

Rainfall in Idaho by month

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

In terms of precipitation, rainfall in Idaho ranges from 0.2 - 1.6 inches per month. December is typically the wettest month, when rainfall can reach 1.6 in. August is typically the driest time to visit Idaho when rainfall is around 0.2 in.

Temperature in Idaho by month

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

If weather is an important factor for your trip to Idaho, 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 75.2 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 30.2 F).

Reviews of airlines servicing Idaho

Get insights into the airlines that provide service to Idaho. 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 Idaho. Reviews last updated June 12, 2025.
Read through reviews of airlines operating flights from St. Louis to Idaho, such as Alaska Airlines, Southwest and Delta. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Boarding

8.1

Comfort

7.8

Food

7.1

Entertainment

7.1

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

Crew

8.5

Overall

8.0

Boarding

8.1

Comfort

7.8

Food

7.1

Entertainment

7.1

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
4,287 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Boarding

8.1

Comfort

7.8

Food

7.1

Entertainment

7.1

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
7,946 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Boarding

8.1

Comfort

7.8

Food

7.1

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Hawaiian Airlines
7.9
Good
2,494 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Boarding

8.1

Comfort

7.8

Food

7.1

Entertainment

7.1

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
8,790 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Boarding

8.1

Comfort

7.8

Food

7.1

Entertainment

7.1

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 St. Louis to Idaho. 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 from for flights from St. Louis to Idaho?

    For a flight from St. Louis to Idaho, you will be flying from Lambert-St Louis. Lambert-St Louis (STL) is just 12.7 mi from the center of the city.

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

    The cheapest airlines for a one-way flight from St. Louis to Idaho are American Airlines ($140), Southwest ($145), and Sun Country Air ($176).

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

    The most popular route from St. Louis to Idaho is Lambert-St Louis - Jackson Hole. You may also consider Lambert-St Louis - Spokane or Lambert-St Louis - Boise Air Term. Gowen Fld.

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

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

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

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

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

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

    Currently, October is the cheapest month in which you can book a flight from St. Louis to Idaho (average of $314). Flying from St. Louis to Idaho in June is currently the most expensive (average of $395). 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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Alternative routes for St. Louis to Idaho

See prices for flight routes from nearby airports that may be better suited for you.
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Top 4 airlines flying from St. Louis to Idaho

Discover the top 4 airlines that operate flights from St. Louis to Idaho. 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 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
American AirlinesCheapest$239Average$534FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$258Average$589FlexibilityNo cancel feeOn-time69%
DeltaCheapest$286Average$492FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$298Average$481FlexibilityNo cancel feeOn-time63%

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