$179 Cheap Flights from Idaho Falls (IDA) to St. Louis (STL)

View $179 flight on Mon, Nov 24, 2025Opens in a new window

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

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

Prices were available within the past 7 days and start at $179 for one-way flights and $339 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Tue, Nov 18 - Sat, Dec 6
IDA
Idaho Falls
STL
St. Louis
$339 Roundtrip, found 2 days ago
$339
Roundtrip
found 2 days ago
Select Delta flight, departing Tue, Nov 18 from Idaho Falls to St. Louis, returning Sat, Dec 6, priced at $339 found 2 days ago
United
Sat, Jan 10 - Tue, Jan 13
IDA
Idaho Falls
STL
St. Louis
$339 Roundtrip, found 2 days ago
$339
Roundtrip
found 2 days ago
Select United flight, departing Sat, Jan 10 from Idaho Falls to St. Louis, returning Tue, Jan 13, priced at $339 found 2 days ago
Delta
Sat, Feb 14 - Tue, Feb 24
IDA
Idaho Falls
STL
St. Louis
$344 Roundtrip, found 2 days ago
$344
Roundtrip
found 2 days ago
Select Delta flight, departing Sat, Feb 14 from Idaho Falls to St. Louis, returning Tue, Feb 24, priced at $344 found 2 days ago
Alaska Airlines
Sun, Feb 15 - Sat, Feb 21
IDA
Idaho Falls
STL
St. Louis
$352 Roundtrip, found 2 days ago
$352
Roundtrip
found 2 days ago
Select Alaska Airlines flight, departing Sun, Feb 15 from Idaho Falls to St. Louis, returning Sat, Feb 21, priced at $352 found 2 days ago
Delta
Fri, Jan 9 - Sat, Jan 10
IDA
Idaho Falls
STL
St. Louis
$354 Roundtrip, found 2 days ago
$354
Roundtrip
found 2 days ago
Select Delta flight, departing Fri, Jan 9 from Idaho Falls to St. Louis, returning Sat, Jan 10, priced at $354 found 2 days ago
Delta
Sat, Feb 14 - Mon, Feb 16
IDA
Idaho Falls
STL
St. Louis
$360 Roundtrip, found 2 days ago
$360
Roundtrip
found 2 days ago
Select Delta flight, departing Sat, Feb 14 from Idaho Falls to St. Louis, returning Mon, Feb 16, priced at $360 found 2 days ago
Hawaiian Airlines
Tue, Feb 3 - Tue, Feb 10
IDA
Idaho Falls
STL
St. Louis
$362 Roundtrip, found 8 hours ago
$362
Roundtrip
found 8 hours ago
Select Hawaiian Airlines flight, departing Tue, Feb 3 from Idaho Falls to St. Louis, returning Tue, Feb 10, priced at $362 found 8 hours ago
Alaska Airlines
Thu, Dec 4 - Sun, Dec 7
IDA
Idaho Falls
STL
St. Louis
$365 Roundtrip, found 3 days ago
$365
Roundtrip
found 3 days ago
Select Alaska Airlines flight, departing Thu, Dec 4 from Idaho Falls to St. Louis, returning Sun, Dec 7, priced at $365 found 3 days ago
Hawaiian Airlines
Tue, Jan 6 - Tue, Jan 20
IDA
Idaho Falls
STL
St. Louis
$366 Roundtrip, found 8 hours ago
$366
Roundtrip
found 8 hours ago
Select Hawaiian Airlines flight, departing Tue, Jan 6 from Idaho Falls to St. Louis, returning Tue, Jan 20, priced at $366 found 8 hours ago
American Airlines
Tue, Jan 20 - Thu, Jan 22
IDA
Idaho Falls
STL
St. Louis
$371 Roundtrip, found 3 hours ago
$371
Roundtrip
found 3 hours ago
Select American Airlines flight, departing Tue, Jan 20 from Idaho Falls to St. Louis, returning Thu, Jan 22, priced at $371 found 3 hours ago

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

January is typically the cheapest month to fly

From $305 - $1,008 per traveler.

Alternative airports near St. Louis

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

Select flight to Lambert-St. Louis Intl. STL. Cheapest option available. Average driving time to city center is 20 minutes. Flights from $405
STL
Lambert-St. Louis Intl.
Cheapest
Average driving time to city center20 min
Flights from $405

Frequently asked questions

How much does a flight from Idaho Falls Regional Airport (IDA) to Lambert-St. Louis Intl. Airport (STL) cost?
Lock in a cheap one-way flight from $179 or cheap return flight from $339 from Idaho Falls Regional Airport (IDA) to Lambert-St. Louis Intl. Airport (STL) 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 Idaho Falls Regional Airport (IDA) to Lambert-St. Louis Intl. Airport (STL)?
The cheapest month to fly from IDA to STL is November, when demand is low. Off-peak months are typically when better flight deals are available between these airports.
What is the cheapest airline that flies from Idaho Falls Regional Airport (IDA) to Lambert-St. Louis Intl. Airport (STL)?
Use the filters on Expedia to compare airlines and find the cheapest carrier that'll fly you from IDA to STL. Then, sort your results by "Price (lowest to highest)" to pick up the best deal available.
How many flights per day from Idaho Falls Regional Airport (IDA) to Lambert-St. Louis Intl. Airport (STL)?
You'll need to take a flight with a layover if you're traveling from Idaho Falls Regional Airport (IDA) to Lambert-St. Louis Intl. Airport (STL). There are no daily direct flights on this route. However, simply 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 IDA to STL?
Usually you'll find the widest variety of flight choices on a Friday. Tuesdays tend to be the quietest.* But this can vary based on the airline, season and other factors.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Idaho Falls Regional Airport (IDA) to Lambert-St. Louis Intl. Airport (STL)?
Choose a flight from Idaho Falls Regional Airport (IDA) to Lambert-St. Louis Intl. Airport (STL) that leaves before 3 PM to reduce the risk of delays and cancellations. Departures after this hour have a 22% higher chance of being canceled, on average.**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 Idaho Falls Regional Airport (IDA) to Lambert-St. Louis Intl. Airport (STL) last-minute?
Last-minute fares from IDA to STL are typically more expensive. For the best rates, start searching for flights early. That said, if you're flexible with your travel dates, it's possible to land a cheap ticket just before your departure.
Is it cheaper to book an IDA to STL flight and hotel package?
Compared with arranging hotels and flights separately, booking an IDA to STL flight and hotel package with Expedia could result in significant savings. Better yet, managing everything in one place will take the stress out of planning your trip. Simply pick your flights and select from our extensive range of hotels, then tailor your trip with extras like tours, activities and car rentals.
Can I cancel or change the date of my flight from Idaho Falls Regional Airport (IDA) to Lambert-St. Louis Intl. Airport (STL)?
If you reserved your IDA to STL flight in the last 24 hours, you may be able to cancel or modify it without fees. Depending on the airline and the type of ticket you have, additional charges may apply for changes after that time. Airline policies and contact information can be found in your itinerary or confirmation email. Or, go to our Customer Service portal if you want more information.

Travel information

Origin airport
Idaho Falls Regional
Destination airport
Lambert-St. Louis Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Hawaiian Airlines, United
Roundtrip price
$338
Distance
1172 mi

Book with confidence

Idaho Falls to St. Louis Flights

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

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 Idaho Falls to St. Louis are during the month of November. You can find some of the cheapest flights from Idaho Falls to St. Louis with Expedia's search tool and vast selection of airlines.

 

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

Sunday is one of the best days to book for cheap flights from Idaho Falls to St. Louis: 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 Idaho Falls to St. Louis

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 Idaho Falls to St. Louis in 2025. You can also book with separate airlines for your outbound and return journeys, from $179 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 Idaho Falls to St. Louis 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 Idaho Falls to St. Louis 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.

 

Idaho Falls to St. Louis Flights

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*Available to One Key members.