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Cheap flights from Idaho to St. Louis from $151

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Idaho to St. Louis departing on 8/17. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
1 adult, Economy, 0 bags

Discover deals from 900+ travel sites with momondo.

Find the cheapest flights from Idaho to St. Louis

Cheap round-trip flights

Enter your travel dates to find the best prices.
Multiple Airlines Logo
1:45 pm - 6:05 pm
TWF
-
STL
27h 20m
1 stop
Multiple Airlines Logo
7:10 pm - 12:00 pm
STL
-
TWF
17h 50m
1 stop
$257Multiple Airlines
Mon, Jul 6 - Sun, Jul 12
Delta Logo
5:45 pm - 12:36 am
BOI
-
STL
5h 51m
1 stop
Delta Logo
6:25 am - 1:38 pm
STL
-
BOI
8h 13m
1 stop
$263Delta
Wed, Sep 9 - Tue, Sep 15
Southwest Logo
3:40 pm - 10:35 pm
BOI
-
STL
5h 55m
1 stop
Southwest Logo
7:00 am - 1:40 pm
STL
-
BOI
7h 40m
2 stops
$270Southwest
Wed, Sep 9 - Tue, Sep 15
Southwest Logo
2:20 pm - 10:45 pm
BOI
-
STL
7h 25m
1 stop
Southwest Logo
8:35 am - 4:00 pm
STL
-
BOI
8h 25m
2 stops
$279Southwest
Tue, Sep 29 - Tue, Oct 6
Frontier Logo
1:25 pm - 6:53 pm
BOI
-
STL
28h 28m
1 stop
Frontier Logo
8:08 pm - 12:29 pm
STL
-
BOI
17h 21m
1 stop
$289Frontier
Thu, Jul 2 - Wed, Jul 8
Frontier Logo
1:25 pm - 6:53 pm
BOI
-
STL
28h 28m
1 stop
Frontier Logo
8:08 pm - 12:29 pm
STL
-
BOI
17h 21m
1 stop
$299Frontier
Thu, Jul 2 - Wed, Jul 8
United Airlines Logo
2:30 pm - 8:43 pm
IDA
-
STL
5h 13m
1 stop
United Airlines Logo
5:10 am - 9:50 am
STL
-
IDA
5h 40m
1 stop
$319United Airlines
Wed, Jul 1 - Thu, Jul 9
Alaska Airlines Logo
12:44 pm - 11:59 pm
GEG
-
STL
9h 15m
1 stop
Alaska Airlines Logo
7:00 am - 11:39 am
STL
-
GEG
6h 39m
1 stop
$331Alaska Airlines
Thu, Oct 22 - Tue, Oct 27
Alaska Airlines Logo
5:12 am - 5:10 pm
GEG
-
STL
9h 58m
1 stop
Alaska Airlines Logo
4:40 pm - 11:54 pm
STL
-
GEG
9h 14m
1 stop
$363Alaska Airlines
Thu, Oct 1 - Sat, Oct 3
United Airlines Logo
4:14 pm - 11:57 pm
IDA
-
STL
6h 43m
1 stop
United Airlines Logo
5:10 am - 9:50 am
STL
-
IDA
5h 40m
1 stop
$365United Airlines
Wed, Jul 22 - Sun, Jul 26

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American Airlines flights from Idaho to St. Louis

Our best American Airlines deals on Idaho to St. Louis flight tickets
American Airlines
Oct 22
GEG3:44 pmSpokane
6h 33m
1 stop
STL12:17 amLambert-St Louis
Oct 27
STL5:40 amLambert-St Louis
8h 18m
1 stop
GEG11:58 amSpokane
$331
American Airlines
Jul 28
GEG3:00 pmSpokane
6h 58m
1 stop
STL11:58 pmLambert-St Louis
Aug 5
STL6:00 amLambert-St Louis
9h 37m
1 stop
GEG1:37 pmSpokane
$341
American Airlines
Oct 22
GEG6:00 amSpokane
6h 45m
1 stop
STL2:45 pmLambert-St Louis
Oct 27
STL5:40 amLambert-St Louis
9h 08m
2 stops
GEG12:48 pmSpokane
$354

Southwest flights from Idaho to St. Louis

Our best Southwest deals on Idaho to St. Louis flight tickets
Southwest
Sep 9
BOI3:40 pmBoise Air Term. Gowen Fld
5h 55m
1 stop
STL10:35 pmLambert-St Louis
Sep 15
STL7:00 amLambert-St Louis
7h 40m
2 stops
BOI1:40 pmBoise Air Term. Gowen Fld
$270
Southwest
Sep 29
BOI2:20 pmBoise Air Term. Gowen Fld
7h 25m
1 stop
STL10:45 pmLambert-St Louis
Oct 6
STL8:35 amLambert-St Louis
8h 25m
2 stops
BOI4:00 pmBoise Air Term. Gowen Fld
$279
Southwest
Sep 29
BOI12:35 pmBoise Air Term. Gowen Fld
8h 05m
2 stops
STL9:40 pmLambert-St Louis
Oct 6
STL8:35 amLambert-St Louis
8h 25m
2 stops
BOI4:00 pmBoise Air Term. Gowen Fld
$356

momondo 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, momondo users made 832,500 searches. Data last updated June 10, 2026.
Use the filters below to find and compare flights from Idaho to St. Louis that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

Twin FallsSt. Louis

TWF - STL

TWFSTL

Twin Falls Joslin

Mon 7/6

1:45 pm-6:05 pm

1 stop27h 20m

Lambert-St Louis

Sun 7/12

7:10 pm-12:00 pm

1 stop17h 50m

$257

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Wed 9/9

5:45 pm-12:36 am

1 stop5h 51m

Lambert-St Louis

Tue 9/15

6:25 am-1:38 pm

1 stop8h 13m

$263

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Wed 9/9

3:40 pm-10:35 pm

1 stop5h 55m

Lambert-St Louis

Tue 9/15

7:00 am-1:40 pm

2 stops7h 40m

$270

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Tue 9/29

2:20 pm-10:45 pm

1 stop7h 25m

Lambert-St Louis

Tue 10/6

8:35 am-4:00 pm

2 stops8h 25m

$279

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Thu 7/2

1:25 pm-6:53 pm

1 stop28h 28m

Lambert-St Louis

Wed 7/8

8:08 pm-12:29 pm

1 stop17h 21m

$289

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Thu 7/2

1:25 pm-6:53 pm

1 stop28h 28m

Lambert-St Louis

Wed 7/8

8:08 pm-12:29 pm

1 stop17h 21m

$299
Quickest round-trip

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Wed 7/1

2:30 pm-8:43 pm

1 stop5h 13m

Lambert-St Louis

Thu 7/9

5:10 am-9:50 am

1 stop5h 40m

$319

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

Thu 10/22

12:44 pm-11:59 pm

1 stop9h 15m

Lambert-St Louis

Tue 10/27

7:00 am-11:39 am

1 stop6h 39m

$331

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

Thu 10/1

5:12 am-5:10 pm

1 stop9h 58m

Lambert-St Louis

Sat 10/3

4:40 pm-11:54 pm

1 stop9h 14m

$363

Idaho FallsSt. Louis

IDA - STL

IDASTL

Idaho Falls Fanning Field

Wed 7/22

4:14 pm-11:57 pm

1 stop6h 43m

Lambert-St Louis

Sun 7/26

5:10 am-9:50 am

1 stop5h 40m

$365

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to St. Louis from

How to get the cheapest flight ticket from Idaho to St. Louis

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest month to fly to St. Louis?

In general, November is the cheapest month to fly from Idaho to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $185. The month of October is another great option to travel to St. Louis, with average flight prices from Idaho averaging around $194.

Can stopping save me money on Idaho to St. Louis flights?

You could potentially save up to 68% on your flight if you consider stops on a Idaho to St. Louis flight.

Cheap Idaho to St. Louis flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Idaho to St. Louis

Fastest flight time

4h 41m

Direct flights

None
The fastest flight from Idaho to St. Louis takes 4h 41m
There are no direct flights from Idaho to St. Louis. There are no popular flight routes from Idaho to St. Louis.
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Frequently asked questions about flying from Idaho to St. Louis

  • When did momondo last update prices for flights from Idaho to Lambert-St Louis Airport?

    Prices for flights from Idaho to Lambert-St Louis Airport are refreshed on a daily basis.

  • How many operators does momondo search for flights from Idaho to Lambert-St Louis Airport?

  • How old do you have to be to fly from Idaho to Lambert-St Louis Airport?

    The minimum age a child must be to fly alone is five but airlines that offer an unaccompanied minor (UNMR) service will have their own age restrictions, including rules around flight length, timings, and stopovers. We always recommend checking with the individual airline you are booking with to travel from Idaho to Lambert-St Louis Airport.

  • What documentation or ID do you need to fly to Lambert-St Louis Airport?

    The required travel and health documents for your Lambert-St Louis Airport trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Lambert-St Louis Airport. We recommend that you seek guidance from your airline or a reliable third party such as IATA.

Best airlines flying from Idaho to St. Louis

Compare and see reviews for airlines that fly from Idaho to St. Louis with momondo
Airline
Rating
Free Cancellation
Price
DeltaPriceFrom $185Free CancellationRating
7.9
8,396 reviews
Search Delta flights
SouthwestPriceFrom $281Free CancellationRating
7.9
4,237 reviews
Search Southwest flights
United AirlinesPriceFrom $283Free CancellationRating
7.4
9,804 reviews
Search United Airlines flights
American AirlinesPriceFrom $350Free CancellationRating
7.1
11,640 reviews
Search American Airlines flights

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
St. Charles
Chesterfield
Fairview Heights
Hermann
Maryland Heights
Florissant
O'Fallon
St. Peters
Collinsville
Alton
Wentzville
Fenton
Clayton
Farmington
Festus
Eureka
Litchfield
Edwardsville
Grafton
Shrewsbury

Why use momondo?

Why should I use momondo to find a flight deal from Idaho to St. Louis?

We help find the flight that best suits your needs, momondo compares prices from hundreds of airlines and travel agents and helps you filter them to find the best flight from Idaho to St. Louis for you.

Can I find flights from Idaho to St. Louis with flexible booking policies on momondo?

Yes. momondo enables you to select and highlight flights to St. Louis from Idaho with this policy.

How can momondo help me find flights from Idaho to St. Louis?

Once you have performed a search for Idaho to St. Louis flights, momondo helps you find the right one by offering useful filters to narrow down your flight selection. Flights can be filtered by multiple factors such as airline, airport and price; but also by other criteria like aircraft type and payment method.

I’m not ready to book a flight from Idaho to St. Louis right now. Can momondo alert me if prices change?

If you are simply researching potential flights to St. Louis, momondo offers a useful price alert feature which will track prices for flights to St. Louis from Idaho and alert you when they change.

An easier way to manage your St. Louis trip

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