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$185 Cheap Flights from Boise (BOI) to St. Louis (STL)

View $185 flight on Thu, Oct 15, 2026Opens in a new window

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

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

Prices were available within the past 7 days and start at $185 for one-way flights and $382 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Southwest Airlines
Tue, Oct 13 - Fri, Oct 16
BOI
Boise
STL
St. Louis
$382 Roundtrip, found 2 days ago
$382
Roundtrip
found 2 days ago
Select Southwest Airlines flight, departing Tue, Oct 13 from Boise to St. Louis, returning Fri, Oct 16, priced at $382 found 2 days ago
American Airlines
Tue, Oct 13 - Fri, Oct 16
BOI
Boise
STL
St. Louis
$385 Roundtrip, found 2 days ago
$385
Roundtrip
found 2 days ago
Select American Airlines flight, departing Tue, Oct 13 from Boise to St. Louis, returning Fri, Oct 16, priced at $385 found 2 days ago
American Airlines
Tue, Oct 13 - Thu, Oct 15
BOI
Boise
STL
St. Louis
$388 Roundtrip, found 3 days ago
$388
Roundtrip
found 3 days ago
Select American Airlines flight, departing Tue, Oct 13 from Boise to St. Louis, returning Thu, Oct 15, priced at $388 found 3 days ago
American Airlines
Thu, Oct 1 - Fri, Oct 2
BOI
Boise
STL
St. Louis
$389 Roundtrip, found 3 days ago
$389
Roundtrip
found 3 days ago
Select American Airlines flight, departing Thu, Oct 1 from Boise to St. Louis, returning Fri, Oct 2, priced at $389 found 3 days ago
Southwest Airlines
Thu, Nov 5 - Wed, Nov 11
BOI
Boise
STL
St. Louis
$390 Roundtrip, found 4 days ago
$390
Roundtrip
found 4 days ago
Select Southwest Airlines flight, departing Thu, Nov 5 from Boise to St. Louis, returning Wed, Nov 11, priced at $390 found 4 days ago
American Airlines
Thu, Oct 15 - Mon, Oct 19
BOI
Boise
STL
St. Louis
$395 Roundtrip, found 3 days ago
$395
Roundtrip
found 3 days ago
Select American Airlines flight, departing Thu, Oct 15 from Boise to St. Louis, returning Mon, Oct 19, priced at $395 found 3 days ago
Southwest Airlines
Tue, Oct 13 - Fri, Oct 16
BOI
Boise
STL
St. Louis
$400 Roundtrip, found 2 days ago
$400
Roundtrip
found 2 days ago
Select Southwest Airlines flight, departing Tue, Oct 13 from Boise to St. Louis, returning Fri, Oct 16, priced at $400 found 2 days ago
Delta
Tue, Nov 24 - Tue, Dec 1
BOI
Boise
STL
St. Louis
$417 Roundtrip, found 7 hours ago
$417
Roundtrip
found 7 hours ago
Select Delta flight, departing Tue, Nov 24 from Boise to St. Louis, returning Tue, Dec 1, priced at $417 found 7 hours ago
Alaska Airlines
Tue, Oct 27 - Tue, Nov 3
BOI
Boise
STL
St. Louis
$427 Roundtrip, found 9 hours ago
$427
Roundtrip
found 9 hours ago
Select Alaska Airlines flight, departing Tue, Oct 27 from Boise to St. Louis, returning Tue, Nov 3, priced at $427 found 9 hours ago
United
Wed, Oct 21 - Tue, Nov 3
BOI
Boise
STL
St. Louis
$437 Roundtrip, found 18 hours ago
$437
Roundtrip
found 18 hours ago
Select United flight, departing Wed, Oct 21 from Boise to St. Louis, returning Tue, Nov 3, priced at $437 found 18 hours ago

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 $539
STL
Lambert-St. Louis Intl.
Cheapest
Average driving time to city center20 min
Flights from $539

What you need to know for your flight from Boise to Lambert-St. Louis Intl.

Boise (BOI) to St. Louis (STL) at a glance

Discover a range of airlines offering flights from Boise (BOI) to St. Louis (STL) on this domestic short-haul journey. Whether you prefer full-service or budget carriers, you can easily compare options to find an itinerary that aligns with your travel budget and schedule while you explore the iconic sights and neighborhoods of St. Louis. Get all the essential details for flights departing from Boise Airport (BOI) to Lambert-St. Louis International Airport (STL).

  • Fastest flight duration: around 4h 15m in-flight, plus roughly 1h 15m layover with one stop
  • Route distance: roughly 1,400 miles (2,250 km)
  • Flights per week: around 11 departures on average
  • Typical fares (one-way): economy tickets often range from $125–$455, depending on seasonality and how far ahead you book

Flights from Boise Airport (BOI) to Lambert-St. Louis International Airport (STL)

Based on recent traveler bookings, here are the top airlines flying from Boise to St. Louis, often selected for their one-stop services. Common layover points include Denver International Airport (DEN) with a layover of about 1 hour, Salt Lake City International Airport (SLC) at approximately 1 hour and 30 minutes, and Minneapolis - St. Paul International Airport (MSP) with a 55-minute layover. These options provide the flexibility to balance price, overall travel time, and cabin class to help you find the ideal itinerary.

  • Delta: This full-service airline provides one-stop flights, capturing about 34% of departures on this route. One-way fares generally fall between $125 and $450. Expect an in-flight duration of 4 hours and 15 minutes, with the total travel time, including layover, being approximately 5 hours and 45 minutes.
  • United: Another full-service option, United accounts for around 26% of departures on this route. Their one-stop service offers one-way fares typically ranging from $140 to $505. In-flight, you can anticipate 4 hours and 15 minutes, while the overall journey time is roughly 5 hours and 45 minutes, including layover.
  • Southwest Airlines: Known as a low-cost carrier, Southwest provides one-stop service on this route, making up about 24% of departures. One-way fares usually range from $125 to $480. The flight time is 4 hours and 15 minutes, with an estimated total travel duration of 5 hours and 45 minutes, factoring in the layover.
  • American Airlines: This full-service carrier offers one-stop flights, representing approximately 9% of departures on this route. Their one-way fares typically range from $125 to $385. Expect an in-flight time of 4 hours and 15 minutes, with a total travel duration of about 5 hours and 45 minutes, including layover.
  • Alaska Airlines: Another full-service airline, Alaska Airlines accounts for roughly 7% of departures on this route. Their one-stop service features one-way fares from $140 to $290. In-flight, the time is 4 hours and 15 minutes, with an overall journey time of about 5 hours and 45 minutes, including layover.

Travelers can enhance their journey from Boise to St. Louis by upgrading their flights. Delta provides options for both first class and premium economy, while United offers first class service.

Best time to fly from Boise (BOI) to St. Louis (STL)

The most popular months for travelers flying from Boise to St. Louis are March, April, and August, when peak temperatures in St. Louis reach up to 77°F in August. If you prefer quieter travel, consider November, the least busy and relatively cheaper time to visit with fewer crowds and temperatures around 46.2°F. For better deals, September usually offers the lowest average one-way fare around $207. Flight availability peaks in July, with approximately 15 flights per week, making it easier to find convenient departure times. January, February, March, April, and December have the fewest flights, with approximately 10 flights per week.

  • Cheapest time to fly: September usually offers good deals with average one-way fare around $207, roughly 16% cheaper than the yearly average.
  • Another budget-friendly time to fly: April typically offers an average one-way fare of around $223.
  • Most flight options: July has the highest number of flights from Boise to St. Louis, with approximately 15 flights per week, giving you more flexibility in scheduling your trip.
calendar iconMonthtemperature iconTemperaturecrowd level iconDemandflights iconWeekly Flightsprice iconAverage one-way Fare
January31.6°F (-0.2°C)Average10$256
February34.9°F (1.6°C)Slightly Low10$284
March46.4°F (8.0°C)Slightly High10$329
April56.1°F (13.4°C)Slightly High10$223
May66.6°F (19.2°C)Average11$239
June76.1°F (24.5°C)Average13$243
July78.6°F (25.9°C)Average15$238
August77.0°F (25.0°C)Slightly High12$228
September70.9°F (21.6°C)Average12$207
October58.6°F (14.8°C)Average13$251
November46.2°F (7.9°C)Slightly Low11$228
December37.8°F (3.2°C)Slightly Low10$240

*Average one-way fare is based on Expedia flight booking data from January 2025 to April 2026 for the specified route and travel class and may change depending on availability, dates, and demand.

Alternative routes from Boise (BOI) to St. Louis (STL)

  • Boise to Springfield (BOI-SPI): Abraham Lincoln Capital Airport (SPI) lies approximately 85 miles from Lambert-St. Louis International Airport (STL), making it a convenient option for travelers heading to the region.
  • Boise to Carbondale (BOI-MDH): Southern Illinois Airport (MDH) is located roughly 90 miles from Lambert-St. Louis International Airport (STL), offering another viable choice for those flying to St. Louis.

How to find the best prices for flights from Boise (BOI) to St. Louis (STL)

Getting some of the best deals on flights from Boise to St. Louis is all about timing and flexibility. Here are some key tips to help you save:

  1. Best times to book and fly: cheaper fares are usually found when booking 2-8 weeks in advance, which coincides with when most travelers make their reservations. Evening departures (6 PM-12 AM) often offer lower prices, while morning flights (5 AM-12 PM) are the most popular. Additionally, flying on Thursday provides both cheaper prices and increased travel demand.
  2. Set up price alerts: stay updated on price changes by using Expedia's Price Tracker. Receive alerts when fares drop for your selected route.
  3. Bundle and save: bundle your flight and hotel to save on Expedia, or unlock a hotel deal after booking your flight.*
  4. Compare flight options: use Expedia's search tool to compare airlines, routes, direct vs. non-direct flights, and flight times. You can also sort by price to find the most affordable options.
  5. Stay flexible with dates: being open to different travel days can sometimes help you find better prices on flights and hotels.
  6. Think about luggage: nowadays, it's important to check the airline's baggage policies to find the best value. That may be paying for an additional carry-on bag or booking a ticket with checked luggage included. Either way, double-check your allowance before confirming your booking to avoid excess baggage fees at the airport.

*Members only. Savings vary and are not available on all bundles. Select hotels.

Arriving at Lambert-St. Louis International Airport from Boise Airport

St. Louis welcomes travelers from Boise with a range of transport options based on price, convenience, and proximity. Here's how to reach St. Louis efficiently:

  • Hotel transfer: Transfers offer a convenient way to reach your hotel in St. Louis, with private rides that can be arranged in advance.
  • Car rental: Renting a car from Lambert-St. Louis International Airport is a great option if you plan to explore and sightsee beyond the city. Browse cheap car rentals at Lambert-St. Louis International Airport on Expedia.
  • Taxi/ride-hailing: Taxis and ride-hailing services may be available from designated pickup areas outside the terminal, check locally on arrival.
  • Public transportation: From Lambert-St. Louis International Airport, Lambert Main Terminal Station, a metro station, is conveniently located just 0.1 miles away on foot, providing easy access to public transport connections.

Frequently asked questions

How much does a flight from Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.) cost?
You can find cheap one-way flights from $185 and cheap return flights from $382 Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.) with Expedia. One-way flights generally range between $205 and $876, and roundtrip flights usually range from $361 to $1141. Flight prices vary based on the month and day of the week you want to travel, as well as the airline and how far in advance you book your ticket. Filter your search on Expedia by "Price (lowest to highest)" to see the cheapest fares first, and use the Price Tracking tool to receive alerts when Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.) ticket fares go up or down.*Typical price ranges based on flights available on Expedia in the last year. Prices include multi-airline options.
What is the cheapest month to fly from Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
September is the cheapest month to fly from Boise, ID (BOI) to St. Louis, MO (STL), with average round-trip fares around $341. This fare is about 19% lower than the average price throughout the year, likely due to reduced travel demand after the summer. Other economical months include January and August.*Averages based on flights available on Expedia in the last year.
Which airlines fly direct from Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
Enter BOI to STL and your travel dates, then apply the 'Nonstop' filter to see only direct flights.
What is the cheapest airline that flies from Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
Frontier Airlines is one of the cheapest airlines offering connecting flights from Boise, ID (BOI) to St. Louis, MO (STL), with round-trip tickets starting from around $150. Use Expedia's search tool to compare the prices and schedules of airlines that fly this route to find the best option for your plans and budget.*Prices based on flights available on Expedia in the last year.
How do I find cheap flights from Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
To find a cheap flight from Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.), be flexible with your dates. Traveling outside of peak vacation months and booking a mid-week flight can help you save. Early morning and late night flights are often more affordable, too. Expedia allows you to compare flight times, airlines and routes all in one place to find low fares. You can also set up Price Tracking and receive alerts when fares go up or down.
What is the best time to fly from Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
For flights from Boise to St. Louis, the best times to fly are in September and August. These months offer return flights at an average price of about $341, making them the most affordable options. Traveling during these months also means you can enjoy pleasant weather and fewer crowds.*Prices based on flights available on Expedia in the last year.
What is the earliest flight from Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
The earliest flight from Boise Airport (BOI) to Lambert-St. Louis International Airport (STL) typically departs at 12:55 AM. Operated by Delta, this flight is a good option for those looking to arrive in St. Louis early. To compare early flights on Expedia, select the "Early Morning" and "Morning" filters in your search.
What are the most popular departure times for flights from Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
The most popular departure times for flights from Boise (BOI) to Lambert-St. Louis Intl. (STL) are in the early morning, from 6am to 9am. About 32% of passengers prefer this time window. Many major carriers, including Southwest Airlines, United Airlines and Southwest Airlines, offer flights during this window. This timing works well because it allows you to arrive in St. Louis with a full day ahead of you.
How long does it take to fly from Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
A flight from BOI to STL with a layover takes around 8 hours 30 minutes, with the route covering approximately 1,380 miles. Keep in mind that actual flight times can vary due to wind patterns, weather, and air traffic.
Can you fly business or first class from Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
First class is available on flights from BOI to STL. First class cabins are available on:

  • American Airlines
  • Delta Air Lines
  • United Airlines

How do I earn miles on a Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.) flight with Expedia?
It's easy to earn miles on a Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.) flight when you book with Expedia. Before you confirm your booking, simply select your frequent flyer program and enter your program number. As a member of One Key™, you can also earn OneKeyCash™* on top of your airline miles when you book with Expedia.*Excludes taxes and fees. OneKeyCash is not redeemable for cash and can only be used on Expedia and other participating brands.
What airports do you fly into for St. Louis from BOI (BOI)?
From BOI (BOI), you can fly into Lambert-St. Louis Intl. (STL) to reach St. Louis. Some flights may connect through major hubs like Denver Intl. (DEN), Harry Reid Intl. (LAS), Sky Harbor Intl. (PHX) before reaching St. Louis. Compare routes and airports on Expedia to find the best flight options for your travel plans.
Is it cheaper to buy a plane ticket from Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.) at the last minute?
Typically, booking a last minute flight from Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.) will be more expensive than booking in advance. As the departure date approaches, there are usually fewer seats available which can drive up the cost. However, if there's some wiggle room with your travel dates and times, you could bag a cheap last-minute fare.
Is it cheaper to book a Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.) flight and hotel package?
Securing a Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.) St Louis Vacation Packages is usually cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels all in one place. Select from our extensive range of stays and then add flights, activities and car rentals to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
If you booked your Boise, ID (BOI) to St. Louis, MO (STL-Lambert-St. Louis Intl.) flight within the last 24 hours, you may be able to modify or cancel it without any fees. Depending on the airline and the type of ticket you have, additional charges may apply for changes beyond this timeframe. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal if you'd like more information.

Travel information

Origin airport
Boise
Destination airport
Lambert-St. Louis Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Southwest Airlines, United
Roundtrip price
$363
Distance
1379 mi

Book with confidence

Boise to St. Louis Flights

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

 

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

Sunday is one of the best days to book for cheap flights from Boise 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 Boise 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 Boise to St. Louis in 2026. You can also book with separate airlines for your outbound and return journeys, from $185 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 Boise 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 Boise 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.

 

Boise to St. Louis Flights

*Flight schedules are subject to change.

*Available to One Key members.

 

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