HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Idaho

$84+ 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 10/15. Fares are subject to change and may not be available on all flights or dates of travel.
STL — BOI
Aug 19 — Aug 261
Tue 8/19
Tue 8/26
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from St. Louis to Idaho with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

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 August 14, 2025.

Round-trip from

$207
(FlightHub)

One-way from

$84
(FlightHub)

Popular in

December

Cheapest in

April

Average price

$385
From Lambert-St Louis to Idaho
Search Deals
One-way flight from Lambert-St Louis to Idaho
Search Deals
Highest demand for flights based on searches. 7% potential increase in price ($35 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($9 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in August 2025
Search Deals

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 August 14, 2025.

This Alaska Airlines deal was found by Cheapflights users on 8/13. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/306:00 amSTL - BOI
1 stop10h 00mAlaska Airlines
Tue 9/305:45 pmBOI - STL
1 stop19h 54mAlaska Airlines
Deal found 8/13$250
This Delta deal was found by Cheapflights users on 8/12. 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 9/25:30 pmSTL - BOI
1 stop6h 30mDelta
Tue 9/910:45 amBOI - STL
1 stop6h 02mDelta
Deal found 8/12$251
This Delta deal was found by Cheapflights users on 8/12. 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 9/25:30 pmSTL - BOI
1 stop7h 26mDelta
Sat 9/63:06 pmBOI - STL
1 stop7h 17mDelta
Deal found 8/12$265
This Alaska Airlines deal was found by Cheapflights users on 8/12. 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 9/26:00 amSTL - BOI
1 stop10h 00mAlaska Airlines
Mon 9/82:28 pmBOI - STL
1 stop8h 31mAlaska Airlines
Deal found 8/12$268
This Delta deal was found by Cheapflights users on 8/12. 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.
Sun 8/318:46 amSTL - BOI
1 stop6h 15mDelta
Tue 9/91:02 pmBOI - STL
1 stop7h 16mDelta
Deal found 8/12$269
This Southwest deal was found by Cheapflights users on 8/13. 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.
Fri 10/316:05 amSTL - BOI
1 stop5h 20mSouthwest
Tue 11/46:10 amBOI - STL
2 stops10h 10mSouthwest
Deal found 8/13$270
This Delta deal was found by Cheapflights users on 8/11. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/278:40 amSTL - GEG
1 stop6h 37mDelta
Tue 9/305:03 pmGEG - STL
1 stop5h 35mDelta
Deal found 8/11$273
This FlightHub deal was found by Cheapflights users on 8/12. 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 9/137:55 pmSTL - GEG
1 stop17h 03mFrontier
Sun 9/2111:53 amGEG - STL
1 stop19h 13mFrontier
Deal found 8/12$276
This Delta deal was found by Cheapflights users on 8/12. 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 9/135:05 pmSTL - BOI
1 stop7h 54mDelta
Sat 9/205:25 amBOI - STL
1 stop5h 05mDelta
Deal found 8/12$279
This Delta deal was found by Cheapflights users on 8/13. 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.
Wed 9/107:35 amSTL - BOI
2 stops11h 41mDelta
Wed 9/175:43 pmBOI - STL
1 stop5h 55mDelta
Deal found 8/13$282
This Delta deal was found by Cheapflights users on 8/12. 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.
Sun 8/318:46 amSTL - BOI
1 stop6h 15mDelta
Sat 9/612:45 pmBOI - STL
1 stop7h 33mDelta
Deal found 8/12$283
This Southwest deal was found by Cheapflights users on 8/13. 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.
Sun 9/286:00 amSTL - BOI
1 stop5h 10mSouthwest
Fri 10/312:35 pmBOI - STL
1 stop10h 35mSouthwest
Deal found 8/13$284

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 August 14, 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. LouisSpokane

STL - GEG

STLGEG

Lambert-St Louis

Sat 9/13

7:55 pm-10:58 am

1 stop17h 03m

Spokane

Sun 9/21

11:53 am-9:06 am

1 stop19h 13m

$207

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Tue 9/30

6:00 am-3:00 pm

1 stop10h 00m

Boise Air Term. Gowen Fld

Tue 9/30

5:45 pm-2:39 pm

1 stop19h 54m

$250

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Tue 9/30

3:35 pm-10:50 pm

1 stop8h 15m

Boise Air Term. Gowen Fld

Wed 10/1

8:00 am-5:34 pm

1 stop8h 34m

$250

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Tue 9/2

6:00 am-3:00 pm

1 stop10h 00m

Boise Air Term. Gowen Fld

Wed 9/3

6:35 am-2:39 pm

1 stop7h 04m

$250

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Tue 9/2

5:30 pm-11:00 pm

1 stop6h 30m

Boise Air Term. Gowen Fld

Tue 9/9

10:45 am-5:47 pm

1 stop6h 02m

$251

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Wed 9/10

5:30 pm-11:58 pm

1 stop7h 28m

Boise Air Term. Gowen Fld

Wed 9/17

5:43 pm-12:38 am

1 stop5h 55m

$251

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Fri 10/31

5:11 am-12:43 pm

1 stop8h 32m

Boise Air Term. Gowen Fld

Tue 11/4

2:06 pm-11:50 pm

1 stop8h 44m

$265

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Tue 9/2

5:30 pm-11:56 pm

1 stop7h 26m

Boise Air Term. Gowen Fld

Sat 9/6

3:06 pm-11:23 pm

1 stop7h 17m

$265

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Tue 9/2

6:00 am-3:00 pm

1 stop10h 00m

Boise Air Term. Gowen Fld

Mon 9/8

2:28 pm-11:59 pm

1 stop8h 31m

$268

St. LouisBoise

STL - BOI

STLBOI

Lambert-St Louis

Tue 9/2

6:00 am-3:00 pm

1 stop10h 00m

Boise Air Term. Gowen Fld

Thu 9/4

9:00 am-5:34 pm

1 stop7h 34m

$268

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/14

Showing 1-10 of 60 results
1
2
3
...
6

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 $399). 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 August 14, 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.

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 August 14, 2025.
Peruse reviews from past customers who have flown with Southwest, Delta, and United Airlines from St. Louis to Idaho to help guide your decision. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,244 reviews

Food

7.0

Crew

8.6

Entertainment

7.5

Boarding

8.1

Comfort

8.0

Overall

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Southwest
8.0
Very good
4,244 reviews
Southwest
8.0
Very good
4,244 reviews

Food

7.0

Crew

8.6

Entertainment

7.5

Boarding

8.1

Comfort

8.0

Overall

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Delta
8.0
Very good
7,980 reviews
Southwest
8.0
Very good
4,244 reviews

Food

7.0

Crew

8.6

Entertainment

7.5

Boarding

8.1

Comfort

8.0

Overall

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
United Airlines
7.4
Good
8,916 reviews
Southwest
8.0
Very good
4,244 reviews

Food

7.0

Crew

8.6

Entertainment

7.5

Boarding

8.1

Comfort

8.0

Overall

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,244 reviews

Food

7.0

Crew

8.6

Entertainment

7.5

Boarding

8.1

Comfort

8.0

Overall

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.

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 Frontier ($84), Hawaiian Airlines ($175), and American Airlines ($193).

  • 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 - Boise Air Term. Gowen Fld or Lambert-St Louis - Spokane.

  • 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 $399). 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

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 St. Louis to Idaho

See prices for flight routes from nearby airports that may be better suited for you.
St. Louis to Seattle flights
St. Louis to Las Vegas flights
Kansas City to Las Vegas flights
St. Louis to Miami flights
Kansas City to Boston flights
St. Louis to Newark flights
St. Louis to Orlando flights
St. Louis to Denver flights
Kansas City to Denver flights
St. Louis to LaGuardia flights
Kansas City to Hobby flights
Kansas City to Newark flights
Kansas City to LaGuardia flights
Kansas City to John F Kennedy Intl flights
Kansas City to O'Hare Intl flights
Kansas City to Orlando flights
St. Louis to John F Kennedy Intl flights
Kansas City to San Diego flights
Kansas City to Seattle flights
St. Louis to Boston flights
St. Louis to Dallas/Fort Worth flights
St. Louis to Reagan-National flights
Kansas City to George Bush Intcntl flights
Kansas City to Atlanta flights
St. Louis to Los Angeles flights
Kansas City to Miami flights
Kansas City to Los Angeles flights
St. Louis to Sky Harbor Intl flights
Kansas City to Sky Harbor Intl flights
St. Louis to Atlanta flights
St. Louis to Fort Lauderdale flights
St. Louis to Salt Lake City flights
St. Louis to Dulles Intl flights
St. Louis to Hobby flights
Kansas City to Dulles Intl flights
St. Louis to O'Hare Intl flights
Kansas City to Dallas/Fort Worth flights
Kansas City to Minneapolis flights
St. Louis to Baltimore flights
Kansas City to San Francisco flights
St. Louis to New Orleans flights
St. Louis to Minneapolis flights
St. Louis to San Francisco flights
St. Louis to San Diego flights
St. Louis to Tampa flights
Springfield to Valparaiso flights
Kansas City to Midway flights
St. Louis to George Bush Intcntl flights
St. Louis to Myrtle Beach flights
Kansas City to Ontario flights

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 August 14, 2025.
AirlineCheapestAverageFlexibilityOn-time
American AirlinesCheapest$239Average$506FlexibilityNo cancel feeOn-time71%
DeltaCheapest$273Average$426FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$287Average$550FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$292Average$440FlexibilityNo cancel feeOn-time63%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.