$175 Cheap Flights from St. Louis (STL) to Idaho Falls (IDA)

View $175 flight on Thu, Oct 30, 2025Opens in a new window

Popular airlines from St. Louis Lambert Intl. Airport (STL) to Idaho Falls Regional Airport (IDA)

Cheap Flights from St. Louis to Idaho Falls (STL-IDA)

Prices were available within the past 7 days and start at $175 for one-way flights and $351 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Tue, Oct 28 - Tue, Nov 11
STL
St. Louis
IDA
Idaho Falls
$351 Roundtrip, found 5 days ago
$351
Roundtrip
found 5 days ago
Select Delta flight, departing Tue, Oct 28 from St. Louis to Idaho Falls, returning Tue, Nov 11, priced at $351 found 5 days ago
Delta
Tue, Oct 7 - Thu, Oct 23
STL
St. Louis
IDA
Idaho Falls
$356 Roundtrip, found 5 days ago
$356
Roundtrip
found 5 days ago
Select Delta flight, departing Tue, Oct 7 from St. Louis to Idaho Falls, returning Thu, Oct 23, priced at $356 found 5 days ago
Alaska Airlines
Thu, Oct 23 - Mon, Oct 27
STL
St. Louis
IDA
Idaho Falls
$367 Roundtrip, found 5 days ago
$367
Roundtrip
found 5 days ago
Select Alaska Airlines flight, departing Thu, Oct 23 from St. Louis to Idaho Falls, returning Mon, Oct 27, priced at $367 found 5 days ago
Hawaiian Airlines
Wed, Feb 25 - Thu, Mar 5
STL
St. Louis
IDA
Idaho Falls
$371 Roundtrip, found 1 day ago
$371
Roundtrip
found 1 day ago
Select Hawaiian Airlines flight, departing Wed, Feb 25 from St. Louis to Idaho Falls, returning Thu, Mar 5, priced at $371 found 1 day ago
Delta
Wed, Jan 7 - Thu, Jan 8
STL
St. Louis
IDA
Idaho Falls
$376 Roundtrip, found 1 day ago
$376
Roundtrip
found 1 day ago
Select Delta flight, departing Wed, Jan 7 from St. Louis to Idaho Falls, returning Thu, Jan 8, priced at $376 found 1 day ago
Alaska Airlines
Sat, Oct 25 - Mon, Oct 27
STL
St. Louis
IDA
Idaho Falls
$379 Roundtrip, found 8 hours ago
$379
Roundtrip
found 8 hours ago
Select Alaska Airlines flight, departing Sat, Oct 25 from St. Louis to Idaho Falls, returning Mon, Oct 27, priced at $379 found 8 hours ago
Delta
Mon, Nov 24 - Thu, Dec 4
STL
St. Louis
IDA
Idaho Falls
$381 Roundtrip, found 3 days ago
$381
Roundtrip
found 3 days ago
Select Delta flight, departing Mon, Nov 24 from St. Louis to Idaho Falls, returning Thu, Dec 4, priced at $381 found 3 days ago
Alaska Airlines
Sat, Nov 8 - Tue, Nov 11
STL
St. Louis
IDA
Idaho Falls
$383 Roundtrip, found 21 hours ago
$383
Roundtrip
found 21 hours ago
Select Alaska Airlines flight, departing Sat, Nov 8 from St. Louis to Idaho Falls, returning Tue, Nov 11, priced at $383 found 21 hours ago
United
Sat, Nov 8 - Tue, Nov 11
STL
St. Louis
IDA
Idaho Falls
$393 Roundtrip, found 21 hours ago
$393
Roundtrip
found 21 hours ago
Select United flight, departing Sat, Nov 8 from St. Louis to Idaho Falls, returning Tue, Nov 11, priced at $393 found 21 hours ago
American Airlines
Thu, May 28 - Tue, Jun 2
STL
St. Louis
IDA
Idaho Falls
$406 Roundtrip, found 6 days ago
$406
Roundtrip
found 6 days ago
Select American Airlines flight, departing Thu, May 28 from St. Louis to Idaho Falls, returning Tue, Jun 2, priced at $406 found 6 days ago

Find the cheapest month to fly from St. Louis (STL) to Idaho Falls (IDA)

January is typically the cheapest month to fly

From $304 - $834 per traveler.

Graph displaying average flight prices per month

Alternative airports near Idaho Falls

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Idaho Falls Regional IDA. Cheapest and Closest option available. Average driving time to city center is 5 minutes. Flights from $431
IDA
Idaho Falls Regional
CheapestClosest
Average driving time to city center5 min
Flights from $431
Flights from St. Louis (STL) to Idaho Falls (IDA)
Origin airport
Lambert-St. Louis Intl.
Destination airport
Idaho Falls Regional
Airlines serving
Alaska Airlines, American Airlines, Delta, Hawaiian Airlines, United
Roundtrip price
$350
Distance
1172 mi

St. Louis to Idaho Falls Flights

The cheapest times to fly from St. Louis to Idaho Falls

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from St. Louis to Idaho Falls are during the month of October. You can find some of the cheapest flights from St. Louis to Idaho Falls with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from St. Louis to Idaho Falls

Sunday is one of the best days to book for cheap flights from St. Louis to Idaho Falls: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from St. Louis to Idaho Falls

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from St. Louis to Idaho Falls in 2025. You can also book with separate airlines for your outbound and return journeys, from $175 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap St. Louis to Idaho Falls flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your St. Louis to Idaho Falls airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Frequently asked questions

How much does a flight from Lambert-St. Louis Intl. Airport (STL) to Idaho Falls Regional Airport (IDA) cost?
Lock in a cheap one-way flight from $175 or cheap return flight from $351 from Lambert-St. Louis Intl. Airport (STL) to Idaho Falls Regional Airport (IDA) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to see our cheapest flight deals on this route.
What is the cheapest month to fly from Lambert-St. Louis Intl. Airport (STL) to Idaho Falls Regional Airport (IDA)?
Flying in October may help you find better deals, as it's the cheapest month for flights between STL and IDA. You'll often find the lowest fares during the off-season.
What is the cheapest airline that flies from Lambert-St. Louis Intl. Airport (STL) to Idaho Falls Regional Airport (IDA)?
Expedia's filter tool lets you easily compare different airlines, travel time and fares all in one place. Choose your preferences, then sort by "Price (lowest to highest)" to see which carrier offers the cheapest STL to IDA flight.
How many flights per day from Lambert-St. Louis Intl. Airport (STL) to Idaho Falls Regional Airport (IDA)?
You'll need to book a flight with a layover if you're traveling from Lambert-St. Louis Intl. Airport (STL) to Idaho Falls Regional Airport (IDA). Direct flights don't operate daily on this route. However, just filter your search to include one or two stops to discover the best option for your trip.
What day of the week has the most flights from STL to IDA?
You'll usually find Tuesday the quietest day for flights, while Fridays are often the busiest.* However this can change from season to season and during public holidays or peak travel times.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Lambert-St. Louis Intl. Airport (STL) to Idaho Falls Regional Airport (IDA)?
To avoid possible delays on the Lambert-St. Louis Intl. Airport (STL) to Idaho Falls Regional Airport (IDA) route, fly before 3 PM. Flights after this time have a 22% higher chance of being canceled.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
Is it cheaper to buy a plane ticket from Lambert-St. Louis Intl. Airport (STL) to Idaho Falls Regional Airport (IDA) last-minute?
Last-minute fares from STL to IDA are typically more expensive. To lock in the best rates, start looking for flights ahead of time. That said, if you're flexible with your travel dates, you may score a cheap ticket just before your departure.
Is it cheaper to book a STL to IDA flight and hotel package?
Compared with arranging hotels and flights separately, booking a STL to IDA flight and hotel package with Expedia could lead to significant savings. Better yet, managing everything in one place will take the stress out of planning your trip. Just pick your flights and select from our wide range of hotels, then personalize your trip with other add-ons like activities, tours and car rentals.
Can I cancel or change the date of my flight from Lambert-St. Louis Intl. Airport (STL) to Idaho Falls Regional Airport (IDA)?
It's usually possible to reschedule or cancel your STL to IDA flight. However, if it's been more than 24 hours since booking, additional fees may apply. Check your airline's policies in your itinerary to see what changes are allowed and if any costs are involved. You'll also find more details on our Customer Service portal.

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*Available to One Key members.