$128 Cheap Flights from St. Louis (STL) to Boise (BOI)

View $128 flight on Wed, Aug 27, 2025Opens in a new window

Popular airlines from St. Louis Lambert Intl. Airport (STL) to Boise Airport (BOI)

Cheap Flights from St. Louis to Boise (STL-BOI)

Prices were available within the past 7 days and start at $128 for one-way flights and $225 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Sat, Aug 9 - Sun, Aug 17
STL
St. Louis
BOI
Boise
$225 Roundtrip, found 4 days ago
$225
Roundtrip
found 4 days ago
Select Frontier Airlines flight, departing Sat, Aug 9 from St. Louis to Boise, returning Sun, Aug 17, priced at $225 found 4 days ago
Frontier Airlines
Wed, Aug 20 - Sun, Sep 7
STL
St. Louis
BOI
Boise
$245 Roundtrip, found 10 hours ago
$245
Roundtrip
found 10 hours ago
Select Frontier Airlines flight, departing Wed, Aug 20 from St. Louis to Boise, returning Sun, Sep 7, priced at $245 found 10 hours ago
Frontier Airlines
Wed, Aug 6 - Sun, Aug 17
STL
St. Louis
BOI
Boise
$255 Roundtrip, found 2 hours ago
$255
Roundtrip
found 2 hours ago
Select Frontier Airlines flight, departing Wed, Aug 6 from St. Louis to Boise, returning Sun, Aug 17, priced at $255 found 2 hours ago
Frontier Airlines
Wed, Aug 20 - Thu, Sep 4
STL
St. Louis
BOI
Boise
$265 Roundtrip, found 10 hours ago
$265
Roundtrip
found 10 hours ago
Select Frontier Airlines flight, departing Wed, Aug 20 from St. Louis to Boise, returning Thu, Sep 4, priced at $265 found 10 hours ago
Bargain Flight
Tue, Oct 14 - Tue, Oct 14
STL
St. Louis
BOI
Boise
$270 Roundtrip, found 4 days ago
$270
Roundtrip
found 4 days ago
Select Bargain Flight flight, departing Tue, Oct 14 from St. Louis to Boise, returning Tue, Oct 14, priced at $270 found 4 days ago
Alaska Airlines
Tue, Oct 14 - Tue, Oct 14
STL
St. Louis
BOI
Boise
$273 Roundtrip, found 4 days ago
$273
Roundtrip
found 4 days ago
Select Alaska Airlines flight, departing Tue, Oct 14 from St. Louis to Boise, returning Tue, Oct 14, priced at $273 found 4 days ago
Frontier Airlines
Wed, Aug 6 - Sun, Aug 10
STL
St. Louis
BOI
Boise
$274 Roundtrip, found 3 days ago
$274
Roundtrip
found 3 days ago
Select Frontier Airlines flight, departing Wed, Aug 6 from St. Louis to Boise, returning Sun, Aug 10, priced at $274 found 3 days ago
Frontier Airlines
Wed, Aug 20 - Sun, Aug 31
STL
St. Louis
BOI
Boise
$275 Roundtrip, found 10 hours ago
$275
Roundtrip
found 10 hours ago
Select Frontier Airlines flight, departing Wed, Aug 20 from St. Louis to Boise, returning Sun, Aug 31, priced at $275 found 10 hours ago
Hawaiian Airlines
Tue, Oct 21 - Tue, Nov 4
STL
St. Louis
BOI
Boise
$279 Roundtrip, found 6 days ago
$279
Roundtrip
found 6 days ago
Select Hawaiian Airlines flight, departing Tue, Oct 21 from St. Louis to Boise, returning Tue, Nov 4, priced at $279 found 6 days ago
Southwest Airlines
Wed, Oct 1 - Tue, Oct 7
STL
St. Louis
BOI
Boise
$279 Roundtrip, found 1 day ago
$279
Roundtrip
found 1 day ago
Select Southwest Airlines flight, departing Wed, Oct 1 from St. Louis to Boise, returning Tue, Oct 7, priced at $279 found 1 day ago

Find the cheapest month to fly from St. Louis (STL) to Boise (BOI)

November is typically the cheapest month to fly

From $180 - $696 per traveler.

Graph displaying average flight prices per month

Alternative airports near Boise

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

Select flight to Boise Airport BOI. Cheapest and Closest option available. Average driving time to city center is 8 minutes. Flights from $393
BOI
Boise Airport
CheapestClosest
Average driving time to city center8 min
Flights from $393
0
Flights from St. Louis (STL) to Boise (BOI)
Origin airport
Lambert-St. Louis Intl.
Destination airport
Boise
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Hawaiian Airlines, Southwest Airlines, United
Roundtrip price
$225
Distance
1379 mi

St. Louis to Boise Flights

The cheapest times to fly from St. Louis to Boise

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

 

The best time to book a flight from St. Louis to Boise

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

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 Boise in 2025. You can also book with separate airlines for your outbound and return journeys, from $128 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 Boise 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 Boise 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 Boise Airport (BOI) cost?
Discover the latest flight deals from STL to BOI by entering your preferred travel dates and searching on Expedia. Easily compare prices by departure date if you have flexibility with your schedule and use handy filters to explore prices for your preferred journey. As a member of One Key™, our free loyalty program, you can use Price Tracking to watch fares and receive notifications if prices go up or down.
What is the cheapest month to fly from STL to BOI?
The cheapest flights from STL to BOI are usually during off-peak season, when demand is lower. To save money, avoid flying during public holidays, school breaks and major local events.
What is the cheapest airline that flies from STL to BOI?
Use the filter tool on Expedia to compare airlines and find the cheapest carrier that'll take you from STL to BOI. Sort your results by "Price (lowest to highest)" to snap up a great deal.
How many flights per day from Lambert-St. Louis Intl. Airport (STL) to Boise Airport (BOI)?
There aren't any daily nonstop flights available from Lambert-St. Louis Intl. Airport (STL) to Boise Airport (BOI). But you can choose flights with layovers. Filter your search on Expedia to include one or more stops, and you'll be cruising above the clouds in no time.
What day of the week has the most flights from STL to BOI?
You'll usually find Tuesday the quietest day for flights, while Fridays are often the busiest.* However this can vary 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 Boise Airport (BOI)?
Opt for a flight from Lambert-St. Louis Intl. Airport (STL) to Boise Airport (BOI) that takes off before 3 PM to reduce the risk of cancellations and delays. Later departures 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 Lambert-St. Louis Intl. Airport (STL) to Boise Airport (BOI) last-minute?
Waiting until just before your departure to book a ticket from STL to BOI generally means paying more. Although you may find some last-minute discounts, there's no guarantee. Keep your travel plans flexible for the best chance of landing a bargain.
Is it cheaper to book a STL to BOI flight and hotel package?
Securing a STL to BOI flight and hotel package is generally cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your trip in one place. Choose from our impressive range of hotels and then add car rentals, flights and activities to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Lambert-St. Louis Intl. Airport (STL) to Boise Airport (BOI)?
Typically, you can cancel or modify your STL to BOI flight. However, there may be additional fees, especially if you made your booking over 24 hours ago. Double-check your itinerary for the airline's fees and guidelines on flight changes, or if you want further details, head to our Customer Service portal.

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*Available to One Key members.