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Cheap flights from Idaho to St. Louis from $138

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 10/28. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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0 bags

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Find the cheapest flights from Idaho to St. Louis

Cheap round-trip flights

Enter your travel dates to find the best prices.
United Airlines Logo
6:20 am - 4:27 pmBOI-STL
9h 07m1 stop
United Airlines Logo
4:55 pm - 9:36 pmSTL-BOI
5h 41m1 stop
$273United Airlines
Find Deal
Tue, Oct 28 - Tue, Nov 4
Delta Logo
11:41 am - 9:23 pmBOI-STL
8h 42m2 stops
Delta Logo
2:29 pm - 12:08 amSTL-BOI
10h 39m2 stops
$274Delta
Find Deal
Sat, Oct 25 - Tue, Oct 28
Multiple Airlines Logo
6:38 pm - 9:07 amGEG-STL
36h 29m2 stops
Multiple Airlines Logo
7:45 pm - 11:08 amSTL-GEG
17h 23m1 stop
$282Multiple Airlines
Find Deal
Mon, Oct 27 - Sat, Nov 8
Southwest Logo
2:15 pm - 9:10 pmBOI-STL
5h 55m1 stop
Southwest Logo
3:00 pm - 10:10 pmSTL-BOI
8h 10m1 stop
$285Southwest
Find Deal
Sat, Oct 25 - Tue, Oct 28
Southwest Logo
2:15 pm - 9:10 pmBOI-STL
5h 55m1 stop
Southwest Logo
5:05 pm - 11:20 pmSTL-BOI
7h 15m2 stops
$290Southwest
Find Deal
Sat, Oct 25 - Tue, Oct 28
Alaska Airlines Logo
11:42 am - 11:59 pmGEG-STL
10h 17m1 stop
Alaska Airlines Logo
7:00 am - 1:58 pmSTL-GEG
8h 58m1 stop
$290Alaska Airlines
Find Deal
Mon, Oct 27 - Sat, Nov 8
American Airlines Logo
12:49 pm - 10:08 pmGEG-STL
7h 19m1 stop
American Airlines Logo
11:42 am - 4:42 pmSTL-GEG
7h 00m1 stop
$291American Airlines
Find Deal
Sat, Nov 1 - Mon, Nov 3
Alaska Airlines Logo
11:43 am - 11:59 pmBOI-STL
11h 16m1 stop
Alaska Airlines Logo
7:00 am - 3:12 pmSTL-BOI
9h 12m1 stop
$293Alaska Airlines
Find Deal
Thu, Nov 13 - Tue, Nov 18
American Airlines Logo
1:26 pm - 10:06 pmBOI-STL
7h 40m1 stop
American Airlines Logo
7:00 am - 1:44 pmSTL-BOI
7h 44m1 stop
$300American Airlines
Find Deal
Sat, Oct 25 - Tue, Oct 28
Multiple Airlines Logo
9:16 pm - 9:07 amGEG-STL
33h 51m2 stops
Multiple Airlines Logo
2:42 pm - 8:26 pmSTL-GEG
7h 44m1 stop
$375Multiple Airlines
Find Deal
Thu, Nov 13 - Sun, Nov 16

United Airlines flights from Idaho to St. Louis

Our best United Airlines deals on Idaho to St. Louis flight tickets
United Airlines
Oct 28
BOI6:20 amBoise Air Term. Gowen Fld
9h 07m
1 stop
STL4:27 pmLambert-St Louis
Nov 4
STL4:55 pmLambert-St Louis
5h 41m
1 stop
BOI9:36 pmBoise Air Term. Gowen Fld
$273
Find similar
United Airlines
Oct 28
BOI6:20 amBoise Air Term. Gowen Fld
9h 07m
1 stop
STL4:27 pmLambert-St Louis
Nov 4
STL1:35 pmLambert-St Louis
10h 53m
2 stops
BOI11:28 pmBoise Air Term. Gowen Fld
$278
Find similar
United Airlines
Oct 29
BOI6:20 amBoise Air Term. Gowen Fld
9h 08m
2 stops
STL4:28 pmLambert-St Louis
Nov 5
STL5:29 pmLambert-St Louis
6h 59m
1 stop
BOI11:28 pmBoise Air Term. Gowen Fld
$280
Find similar

Delta flights from Idaho to St. Louis

Our best Delta deals on Idaho to St. Louis flight tickets
Delta
Oct 25
BOI11:41 amBoise Air Term. Gowen Fld
8h 42m
2 stops
STL9:23 pmLambert-St Louis
Oct 28
STL2:29 pmLambert-St Louis
10h 39m
2 stops
BOI12:08 amBoise Air Term. Gowen Fld
$274
Find similar
Delta
Nov 24
GEG4:43 pmSpokane
6h 03m
1 stop
STL12:46 amLambert-St Louis
Dec 2
STL8:05 pmLambert-St Louis
5h 54m
1 stop
GEG11:59 pmSpokane
$283
Find similar
Delta
Oct 22
GEG5:45 amSpokane
6h 47m
1 stop
STL2:32 pmLambert-St Louis
Oct 25
STL6:50 amLambert-St Louis
10h 07m
2 stops
GEG2:57 pmSpokane
$294
Find similar

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 October 1, 2025.
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

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Tue 10/28

6:20 am-4:27 pm

1 stop9h 07m

Lambert-St Louis

Tue 11/4

4:55 pm-9:36 pm

1 stop5h 41m

$273

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Sat 10/25

11:41 am-9:23 pm

2 stops8h 42m

Lambert-St Louis

Tue 10/28

2:29 pm-12:08 am

2 stops10h 39m

$274

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

Mon 10/27

6:38 pm-9:07 am

2 stops36h 29m

Lambert-St Louis

Sat 11/8

7:45 pm-11:08 am

1 stop17h 23m

$282

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Sat 10/25

2:15 pm-9:10 pm

1 stop5h 55m

Lambert-St Louis

Tue 10/28

3:00 pm-10:10 pm

1 stop8h 10m

$285

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Sat 10/25

2:15 pm-9:10 pm

1 stop5h 55m

Lambert-St Louis

Tue 10/28

5:05 pm-11:20 pm

2 stops7h 15m

$290

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

Mon 10/27

11:42 am-11:59 pm

1 stop10h 17m

Lambert-St Louis

Sat 11/8

7:00 am-1:58 pm

1 stop8h 58m

$290

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

Sat 11/1

12:49 pm-10:08 pm

1 stop7h 19m

Lambert-St Louis

Mon 11/3

11:42 am-4:42 pm

1 stop7h 00m

$291

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Thu 11/13

11:43 am-11:59 pm

1 stop11h 16m

Lambert-St Louis

Tue 11/18

7:00 am-3:12 pm

1 stop9h 12m

$293

BoiseSt. Louis

BOI - STL

BOISTL

Boise Air Term. Gowen Fld

Sat 10/25

1:26 pm-10:06 pm

1 stop7h 40m

Lambert-St Louis

Tue 10/28

7:00 am-1:44 pm

1 stop7h 44m

$300

SpokaneSt. Louis

GEG - STL

GEGSTL

Spokane

Thu 11/13

9:16 pm-9:07 am

2 stops33h 51m

Lambert-St Louis

Sun 11/16

2:42 pm-8:26 pm

1 stop7h 44m

$375

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, April 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 $334. The month of June is another great option to travel to St. Louis, with average flight prices from Idaho averaging around $362.

What is the cheapest day to depart on your flight to St. Louis?

The cheapest day to depart on your flight to St. Louis is on a Tuesday when prices can be found for as low as $391. This is often the case because there is less demand to fly during this day of the week. If your travel schedule is flexible, try to avoid departing on a Monday because tickets tend to average around $561. These prices are subject to change though, so be sure to set up a Price Alert for flights to St. Louis.

What is the cheapest time of day to depart on your flight to St. Louis?

Flying to St. Louis from Idaho in the afternoon is the least expensive time of day to depart. momondo users have found prices as low as $410 when looking at flights departing in the afternoon. In the morning is when there is more demand to fly to St. Louis, so prices are often more expensive at around $496 per ticket.

How far in advance should I book a flight to St. Louis?

You are more likely to see cheaper flights to St. Louis from Idaho when booking weeks ahead of your departure date. In general, you can expect to find flights to St. Louis for around $444 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to St. Louis from Idaho for as low as $317 on momondo.

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

You could potentially save up to 19% 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

Direct flights

None
There are no direct flights from Idaho to St. Louis. There are no popular flight routes from Idaho to St. Louis.
Search flight deals

  • 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 $209Free CancellationRating
7.9
7,961 reviews
Search Delta flights
American AirlinesPriceFrom $226Free CancellationRating
7.2
10,000 reviews
Search American Airlines flights
Alaska AirlinesPriceFrom $278Free CancellationRating
8.0
10,000 reviews
Search Alaska Airlines flights
SouthwestPriceFrom $286Free CancellationRating
8.0
4,248 reviews
Search Southwest flights
United AirlinesPriceFrom $286Free CancellationRating
7.4
8,929 reviews
Search United 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
Hermann
Fairview Heights
Florissant
Maryland Heights
O'Fallon
Collinsville
Fenton
Wentzville
St. Peters
Alton
Farmington
Festus
Glencoe
Clayton
Edwardsville
Eureka
Litchfield
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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