$90 Cheap Flights from Boston (BOS) to St. Louis (STL)

View $90 flight on Sun, Sep 7, 2025Opens in a new window

Popular airlines from Logan International Airport (BOS) to St. Louis Lambert Intl. Airport (STL)

  • Plan, book, fly with confidence

  • trending down icon
    Be in the know
    Get alerts if flight prices drop or rise*
  • bex rewards loyalty icon
    Book smarter
    Save up to 30% on select hotels after you book a flight*
  • one key icon
    Earn twice
    Earn your airline miles on top of our OneKeyCash
    Learn about One Key

Cheap Flights from Boston to St. Louis (BOS-STL)

Prices were available within the past 7 days and start at $90 for one-way flights and $179 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Spirit Airlines
Mon, Aug 25 - Sun, Aug 31
BOS
Boston
STL
St. Louis
$179 Roundtrip, found 1 hour ago
$179
Roundtrip
found 1 hour ago
Select Spirit Airlines flight, departing Mon, Aug 25 from Boston to St. Louis, returning Sun, Aug 31, priced at $179 found 1 hour ago
Spirit Airlines
Sat, Aug 2 - Thu, Aug 14
BOS
Boston
STL
St. Louis
$183 Roundtrip, found 2 days ago
$183
Roundtrip
found 2 days ago
Select Spirit Airlines flight, departing Sat, Aug 2 from Boston to St. Louis, returning Thu, Aug 14, priced at $183 found 2 days ago
Spirit Airlines
Sun, Sep 21 - Thu, Sep 25
BOS
Boston
STL
St. Louis
$189 Roundtrip, found 5 hours ago
$189
Roundtrip
found 5 hours ago
Select Spirit Airlines flight, departing Sun, Sep 21 from Boston to St. Louis, returning Thu, Sep 25, priced at $189 found 5 hours ago
Spirit Airlines
Tue, Aug 12 - Mon, Aug 18
BOS
Boston
STL
St. Louis
$193 Roundtrip, found 1 hour ago
$193
Roundtrip
found 1 hour ago
Select Spirit Airlines flight, departing Tue, Aug 12 from Boston to St. Louis, returning Mon, Aug 18, priced at $193 found 1 hour ago
Spirit Airlines
Fri, Aug 29 - Thu, Sep 4
BOS
Boston
STL
St. Louis
$199 Roundtrip, found 1 hour ago
$199
Roundtrip
found 1 hour ago
Select Spirit Airlines flight, departing Fri, Aug 29 from Boston to St. Louis, returning Thu, Sep 4, priced at $199 found 1 hour ago
Spirit Airlines
Sun, Sep 21 - Thu, Sep 25
BOS
Boston
STL
St. Louis
$203 Roundtrip, found 5 hours ago
$203
Roundtrip
found 5 hours ago
Select Spirit Airlines flight, departing Sun, Sep 21 from Boston to St. Louis, returning Thu, Sep 25, priced at $203 found 5 hours ago
Southwest Airlines
Wed, Oct 15 - Wed, Oct 22
BOS
Boston
STL
St. Louis
$217 Roundtrip, found 23 hours ago
$217
Roundtrip
found 23 hours ago
Select Southwest Airlines flight, departing Wed, Oct 15 from Boston to St. Louis, returning Wed, Oct 22, priced at $217 found 23 hours ago
American Airlines
Sat, Oct 25 - Wed, Oct 29
BOS
Boston
STL
St. Louis
$217 Roundtrip, found 18 hours ago
$217
Roundtrip
found 18 hours ago
Select American Airlines flight, departing Sat, Oct 25 from Boston to St. Louis, returning Wed, Oct 29, priced at $217 found 18 hours ago
Delta
Mon, Sep 29 - Sun, Oct 5
BOS
Boston
STL
St. Louis
$228 Roundtrip, found 1 hour ago
$228
Roundtrip
found 1 hour ago
Select Delta flight, departing Mon, Sep 29 from Boston to St. Louis, returning Sun, Oct 5, priced at $228 found 1 hour ago
United
Wed, Oct 1 - Tue, Oct 7
BOS
Boston
STL
St. Louis
$277 Roundtrip, found 1 hour ago
$277
Roundtrip
found 1 hour ago
Select United flight, departing Wed, Oct 1 from Boston to St. Louis, returning Tue, Oct 7, priced at $277 found 1 hour ago

Find the cheapest month to fly from Boston (BOS) to St. Louis (STL)

September is typically the cheapest month to fly

From $123 - $309 per traveler.

Graph displaying average flight prices per month

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 $278
STL
Lambert-St. Louis Intl.
Cheapest
Average driving time to city center20 min
Flights from $278
Flights from Boston (BOS) to St. Louis (STL)
Origin airport
Logan Intl.
Destination airport
Lambert-St. Louis Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Southwest Airlines, Spirit Airlines, United
Roundtrip price
$129
Distance
1043 mi
Average flight time
2 hours 2 mins

Boston to St. Louis Flights

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

 

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

Sunday is one of the best days to book for cheap flights from Boston 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 Boston 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 Boston to St. Louis in 2025. You can also book with separate airlines for your outbound and return journeys, from $90 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 Boston 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 Boston 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.

 

Frequently asked questions

How much does a flight from Logan Intl. Airport (BOS) to Lambert-St. Louis Intl. Airport (STL) cost?
Cheap return flights from Logan Intl. Airport (BOS) to Lambert-St. Louis Intl. Airport (STL) start at $257. This information is based on the cheapest price found on Expedia for this return journey departing within the next three months. This airfare is for a Southwest Airlines flight leaving BOS on July 27 2025 and touching down at STL. The price was last updated on July 1 2025 and has not changed since.
What is the cheapest month to fly from BOS to STL?
Look for direct flights from BOS to STL in October to score cheaper fares. You can find a one-way Southwest Airlines flight for $129 leaving on October 1 2025. This price is based on the cheapest direct flight found on Expedia for this route in the next 330 days. The price was last updated on July 1 2025 and remains unchanged.
Which airlines fly direct from Logan Intl. Airport (BOS) to Lambert-St. Louis Intl. Airport (STL)?
Hop on a direct flight with American Airlines and fly straight from Logan Intl. Airport (BOS) to Lambert-St. Louis Intl. Airport (STL).
What is the cheapest airline that flies from BOS to STL?
With prices starting from $129 for a one-way journey from BOS to STL, Southwest Airlines is currently the cheapest airline on this route. This fare is based on the lowest price found on Expedia departing within the next three months. The flight takes off from BOS on September 25 2025. Prices were last updated on July 1 2025 and have not changed since.
How many flights per day from Logan Intl. Airport (BOS) to Lambert-St. Louis Intl. Airport (STL)?
When jetting out of Logan Intl. Airport (BOS), you'll have your pick from an average of 2 daily direct flights to Lambert-St. Louis Intl. Airport (STL).
What are the most popular departure times for flights from Logan Intl. Airport (BOS) to Lambert-St. Louis Intl. Airport (STL)?
More people fly between BOS and STL at 6 AM than at any other time of day. Looking for a quieter experience? Travel outside of rush hours and it's possible you'll save on your ticket as well.
What day of the week has the most flights from BOS to STL?
Sunday offers the most flights from Logan Intl. Airport (BOS) to Lambert-St. Louis Intl. Airport (STL). Consider jetting off on this day and you'll have a greater chance of finding a departure that fits your itinerary.
What is the earliest flight from Logan Intl. Airport (BOS) to Lambert-St. Louis Intl. Airport (STL)?
Catch the earliest flight at around 6:15AM UTC-5, departing from Logan Intl. Airport (BOS). You'll be in the air for around 3h 15m, landing at Lambert-St. Louis Intl. Airport (STL) at approximately 8:30AM UTC-6.
How long does it take to fly from Logan Intl. Airport (BOS) to Lambert-St. Louis Intl. Airport (STL)?
The average flight time from BOS to STL is 3 hours and 18 minutes, covering a distance of 1,050 mi.
What is the best time to fly from Logan Intl. Airport (BOS) to Lambert-St. Louis Intl. Airport (STL)?
To avoid possible delays on the Logan Intl. Airport (BOS) to Lambert-St. Louis Intl. Airport (STL) route, fly before 3 PM. Flights after this time have a 22% higher chance of cancellation.**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.
What airports do you fly into for St. Louis from Logan Intl. Airport (BOS)?
If you're on a direct flight from Logan Intl. Airport (BOS) to St. Louis, Lambert-St. Louis Intl. Airport (STL) is the only airport you can touch down at.
Is it cheaper to buy a plane ticket from Logan Intl. Airport (BOS) to Lambert-St. Louis Intl. Airport (STL) last-minute?
Waiting until just before your trip to book a ticket from BOS to STL often results in higher prices. While you might find some last-minute offers, they're not always guaranteed. Be flexible with your itinerary to maximize your chances of scoring a bargain.
Is it cheaper to book a BOS to STL flight and hotel package?
Compared with arranging flights and hotels separately, booking a BOS to STL flight and hotel package with Expedia could lead to significant savings. Better yet, having it all in one place takes the hassle out of planning your trip. Just pick your flights and choose from our wide range of stays, then tailor your trip with extras like tours, activities and car rentals.
Can I cancel or change the date of my flight from Logan Intl. Airport (BOS) to Lambert-St. Louis Intl. Airport (STL)?
Typically, you can cancel or reschedule your BOS to STL flight. However, there may be additional fees, especially if you made your booking over 24 hours ago. Check your itinerary for the airline's fees and policies on flight changes, or if you'd like further information, go to our Customer Service portal.

Explore a world of travel with Expedia

*Available to One Key members.