Latest deals
Insights
When to book
FAQs
Reviews
Price Alerts

Cheap flights from Boston to St. Louis from $85

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Boston to St. Louis departing on 9/17. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
0 bags

Discover deals from 900+ travel sites with momondo.

Save money when you book flights with momondo

Big names and deals

Big names and deals

Search 100s of travel sites to compare prices.

Filter for what you want

Filter for what you want

Free Wi-Fi? Stopover? Instantly customize your results.

Trusted and free

Trusted and free

We’re completely free to use - no hidden charges or fees.

Price Alerts

Price Alerts

Not ready to book? to track prices.
Search flight deals

Find the cheapest flights from Boston to St. Louis

Cheap round-trip flights

Logo
3:00 pm - 3:04 pmBOS-STL
25h 04m2 stops
Logo
10:57 am - 11:26 amSTL-BOS
23h 29m1 stop
$260
Find Deal
Wed, Oct 1 - Sun, Oct 5
American Airlines Logo
11:14 am - 4:04 pmBOS-STL
5h 50m1 stop
American Airlines Logo
7:00 pm - 10:37 pmSTL-BOS
2h 37mnonstop
$261American Airlines
Find Deal
Tue, Oct 14 - Tue, Oct 14
Spirit Airlines Logo
12:49 pm - 10:02 amBOS-STL
22h 13m2 stops
Spirit Airlines Logo
10:57 am - 11:59 pmSTL-BOS
12h 02m1 stop
$266Spirit Airlines
Find Deal
Mon, Oct 6 - Thu, Oct 9
Logo
6:00 am - 5:31 pmBOS-STL
12h 31m1 stop
Logo
12:20 pm - 12:40 amSTL-BOS
11h 20m1 stop
$268
Find Deal
Thu, Dec 11 - Sun, Dec 14
Spirit Airlines Logo
8:24 pm - 6:10 pmBOS-STL
22h 46m1 stop
Spirit Airlines Logo
10:57 am - 11:59 pmSTL-BOS
12h 02m1 stop
$275Spirit Airlines
Find Deal
Fri, Oct 10 - Tue, Oct 14
Frontier Logo
9:50 am - 10:16 amBOS-STL
25h 26m1 stop
Frontier Logo
11:32 am - 8:55 amSTL-BOS
20h 23m1 stop
$287Frontier
Find Deal
Thu, Oct 23 - Sun, Oct 26
United Airlines Logo
6:55 pm - 11:57 pmBOS-STL
6h 02m1 stop
United Airlines Logo
6:30 am - 2:15 pmSTL-BOS
6h 45m2 stops
$312United Airlines
Find Deal
Fri, Oct 17 - Sat, Oct 18
United Airlines Logo
6:56 pm - 11:44 pmBOS-STL
5h 48m1 stop
United Airlines Logo
5:00 am - 11:02 amSTL-BOS
5h 02m1 stop
$317United Airlines
Find Deal
Tue, Sep 23 - Thu, Sep 25
Frontier Logo
10:53 am - 9:06 amBOS-STL
23h 13m2 stops
Frontier Logo
4:00 pm - 9:58 amSTL-BOS
16h 58m1 stop
$319Frontier
Find Deal
Fri, Sep 5 - Sun, Sep 7
Southwest Logo
7:30 am - 9:35 amBOS-STL
3h 05mnonstop
Southwest Logo
2:25 pm - 6:00 pmSTL-BOS
2h 35mnonstop
$321Southwest
Find Deal
Tue, Oct 28 - Wed, Oct 29

Frontier flights from Boston to St. Louis

Our best Frontier deals on Boston to St. Louis flight tickets
Frontier
Sep 6
BOS8:38 amBoston Logan Intl
25h 28m
2 stops
STL9:06 amLambert-St Louis
Sep 7
STL4:00 pmLambert-St Louis
16h 58m
1 stop
BOS9:58 amBoston Logan Intl
$263
Find similar
Frontier
Sep 5
BOS10:53 amBoston Logan Intl
23h 13m
2 stops
STL9:06 amLambert-St Louis
Sep 7
STL4:00 pmLambert-St Louis
16h 58m
1 stop
BOS9:58 amBoston Logan Intl
$273
Find similar
Frontier
Sep 5
BOS10:53 amBoston Logan Intl
23h 13m
2 stops
STL9:06 amLambert-St Louis
Sep 7
STL4:00 pmLambert-St Louis
16h 58m
1 stop
BOS9:58 amBoston Logan Intl
$274
Find similar

Spirit Airlines flights from Boston to St. Louis

Our best Spirit Airlines deals on Boston to St. Louis flight tickets
Spirit Airlines
Oct 6
BOS12:49 pmBoston Logan Intl
22h 13m
2 stops
STL10:02 amLambert-St Louis
Oct 9
STL10:57 amLambert-St Louis
12h 02m
1 stop
BOS11:59 pmBoston Logan Intl
$266
Find similar
Spirit Airlines
Oct 10
BOS8:24 pmBoston Logan Intl
22h 46m
1 stop
STL6:10 pmLambert-St Louis
Oct 14
STL10:57 amLambert-St Louis
12h 02m
1 stop
BOS11:59 pmBoston Logan Intl
$275
Find similar
Spirit Airlines
Oct 1
BOS12:20 pmBoston Logan Intl
22h 20m
3 stops
STL9:40 amLambert-St Louis
Oct 5
STL10:57 amLambert-St Louis
12h 02m
1 stop
BOS11:59 pmBoston Logan Intl
$300
Find similar

momondo Fare Finder

 
Customize your flight search to find flights from Boston to St. Louis that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, momondo users made 832,500 searches. Data last updated August 26, 2025.
Use the filters below to find and compare flights from Boston to St. Louis that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

BostonSt. Louis

BOS - STL

BOSSTL

Boston Logan Intl

Wed 10/1

3:00 pm-3:04 pm

2 stops25h 04m

Lambert-St Louis

Sun 10/5

10:57 am-11:26 am

1 stop23h 29m

$260

BostonSt. Louis

BOS - STL

BOSSTL

Boston Logan Intl

Tue 10/14

11:14 am-4:04 pm

1 stop5h 50m

Lambert-St Louis

Tue 10/14

7:00 pm-10:37 pm

Nonstop2h 37m

$261

BostonSt. Louis

BOS - STL

BOSSTL

Boston Logan Intl

Mon 10/6

12:49 pm-10:02 am

2 stops22h 13m

Lambert-St Louis

Thu 10/9

10:57 am-11:59 pm

1 stop12h 02m

$266

BostonSt. Louis

BOS - STL

BOSSTL

Boston Logan Intl

Thu 12/11

6:00 am-5:31 pm

1 stop12h 31m

Lambert-St Louis

Sun 12/14

12:20 pm-12:40 am

1 stop11h 20m

$268

BostonSt. Louis

BOS - STL

BOSSTL

Boston Logan Intl

Fri 10/10

8:24 pm-6:10 pm

1 stop22h 46m

Lambert-St Louis

Tue 10/14

10:57 am-11:59 pm

1 stop12h 02m

$275

BostonSt. Louis

BOS - STL

BOSSTL

Boston Logan Intl

Thu 10/23

9:50 am-10:16 am

1 stop25h 26m

Lambert-St Louis

Sun 10/26

11:32 am-8:55 am

1 stop20h 23m

$287

BostonSt. Louis

BOS - STL

BOSSTL

Boston Logan Intl

Fri 10/17

6:55 pm-11:57 pm

1 stop6h 02m

Lambert-St Louis

Sat 10/18

6:30 am-2:15 pm

2 stops6h 45m

$312

BostonSt. Louis

BOS - STL

BOSSTL

Boston Logan Intl

Tue 9/23

6:56 pm-11:44 pm

1 stop5h 48m

Lambert-St Louis

Thu 9/25

5:00 am-11:02 am

1 stop5h 02m

$317

BostonSt. Louis

BOS - STL

BOSSTL

Boston Logan Intl

Fri 9/5

10:53 am-9:06 am

2 stops23h 13m

Lambert-St Louis

Sun 9/7

4:00 pm-9:58 am

1 stop16h 58m

$319

BostonSt. Louis

BOS - STL

BOSSTL

Boston Logan Intl

Tue 10/28

7:30 am-9:35 am

Nonstop3h 05m

Lambert-St Louis

Wed 10/29

2:25 pm-6:00 pm

Nonstop2h 35m

$321

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
1
2

See travel insights to St. Louis from

How to get the cheapest flight ticket from Boston to St. Louis

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest month to fly to St. Louis?

In general, August is the cheapest month to fly from Boston to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $384. The month of September is another great option to travel to St. Louis, with average flight prices from Boston averaging around $386.

What is the cheapest day to depart on your flight to St. Louis?

The cheapest day to depart on your flight to St. Louis is on a Wednesday when prices can be found for as low as $422. This is often the case because there is less demand to fly during this day of the week. If your travel schedule is flexible, try to avoid departing on a Sunday because tickets tend to average around $503. These prices are subject to change though, so be sure to set up a Price Alert for flights to St. Louis.

What is the cheapest time of day to depart on your flight to St. Louis?

Flying to St. Louis from Boston in the evening is the least expensive time of day to depart. momondo users have found prices as low as $429 when looking at flights departing in the evening. At noon is when there is more demand to fly to St. Louis, so prices are often more expensive at around $453 per ticket.

What is the cheapest Boston Logan Intl to Lambert-St Louis flight route?

Fly from Boston Logan Intl to Lambert-St Louis for the best Boston Logan Intl - Lambert-St Louis flight prices

How far in advance should I book a flight to St. Louis?

You are more likely to see cheaper flights to St. Louis from Boston when booking weeks ahead of your departure date. In general, you can expect to find flights to St. Louis for around $437 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to St. Louis from Boston for as low as $390 on momondo.

What cabin class options are available on Boston Logan Intl to Lambert-St Louis flights?

There are 3 cabin classes available to choose from on Boston Logan Intl to Lambert-St Louis flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Can stopping save me money on Boston to St. Louis flights?

You could potentially save up to 3% on your flight if you consider stops on a Boston to St. Louis flight.

How have Boston to St. Louis flight prices changed over time?

As of August 2025, prices for Boston to St. Louis flights are approximately 37% cheaper when compared to flights at the same time last year.

When to book flights from Boston to St. Louis

Are you open to changing your travel dates? Check out the ideal times to fly from Boston to St. Louis according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap Boston to St. Louis (BOS to STL) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Boston to St. Louis

Best Price Found

$178

Fastest flight time

2h 55m

Direct flights

Every day

Airports in St. Louis

1 airport
The best one-way flight to St. Louis from Boston in the past 72 hours is $178. The best round-trip flight deal from Boston to St. Louis found on momondo in the last 72 hours is $305.
The fastest flight from Boston to St. Louis takes 2h 55m
Direct flights go from Boston to St. Louis every day.
There is 1 airport near St. Louis: Lambert-St Louis (STL)
Search flight deals

  • How far is Boston Logan Intl to Lambert-St Louis by plane?

    Lambert-St Louis is 1035.0 mi away from Boston Logan Intl. Flights usually cover this in 3h 05m, depending on flying conditions and air traffic around both airports.

  • When did momondo last update prices for flights from Boston Logan Intl Airport to Lambert-St Louis Airport?

    Prices for flights from Boston Logan Intl Airport to Lambert-St Louis Airport were last updated today.

  • How many operators does momondo search for flights from Boston Logan Intl Airport to Lambert-St Louis Airport?

  • How old do you have to be to fly from Boston Logan Intl Airport to Lambert-St Louis Airport?

    The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Boston Logan Intl Airport to Lambert-St Louis Airport.

  • What documentation or ID do you need to fly to Lambert-St Louis Airport?

    The travel and health documents you'll need for your trip to Lambert-St Louis Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at Lambert-St Louis Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

  • What is the most popular plane model from Boston to St. Louis?

  • What is the most popular airline from Boston to St. Louis?

Best airlines flying from Boston to St. Louis

Compare and see reviews for airlines that fly from Boston to St. Louis with momondo
Airline
Rating
Free Cancellation
Price
Spirit AirlinesPriceFrom $83Free CancellationRating
6.3
8,031 reviews
Search Spirit Airlines flights
FrontierPriceFrom $113Free CancellationRating
5.8
3,200 reviews
Search Frontier flights
DeltaPriceFrom $216Free CancellationRating
7.9
7,979 reviews
Search Delta flights
United AirlinesPriceFrom $257Free CancellationRating
7.4
8,943 reviews
Search United Airlines flights
American AirlinesPriceFrom $297Free CancellationRating
7.2
10,000 reviews
Search American Airlines flights
SouthwestPriceFrom $323Free CancellationRating
8.0
4,242 reviews
Search Southwest flights

  • Southwest Flights From Boston to St. Louis

    Southwest operates around 15 flights from Boston to St. Louis every week. The average price of these flights found in the last 72 hours has been $459, but momondo users have found Southwest deals from Boston to St. Louis from as low as $323 round-trip. Southwest has been scored 8.0/10 in 4,243 reviews.

  • American Airlines Flights From Boston to St. Louis

    The best American Airlines deal for Boston to St. Louis flight tickets found on momondo in the last 72 hours was $297, round-trip. It should be noted that an average American Airlines flight deal for this route in this time was higher, at $458 round-trip. American Airlines operates 6 flights out of Boston into St. Louis in an average week, so prices vary by time and availability. 10,000 American Airlines reviews by users on momondo have scored the airline at 7.2/10.

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
St. Charles
Chesterfield
Hermann
Fairview Heights
Maryland Heights
Florissant
O'Fallon
Fenton
Collinsville
Wentzville
Alton
St. Peters
Farmington
Festus
Glencoe
Clayton
Edwardsville
Eureka
Litchfield
Shrewsbury

Why use momondo?

Why should I use momondo to find a flight deal from Boston to St. Louis?

We help find the flight that best suits your needs, momondo compares prices from hundreds of airlines and travel agents and helps you filter them to find the best flight from Boston to St. Louis for you.

Can I find flights from Boston to St. Louis with flexible booking policies on momondo?

Yes. All flights to St. Louis from Boston on momondo can be compared and filtered by various policies on offer, including flexible booking.

How can momondo help me find flights from Boston to St. Louis?

momondo helps you find the best flight between Boston and St. Louis by providing filters to narrow your choice of flights to those matching your criteria. You can select flights based on numerous factors such as price, departure and landing times, airport and airline.

I’m not ready to book a flight from Boston to St. Louis right now. Can momondo alert me if prices change?

Yes momondo offers price alerts on flights to St. Louis from Boston. After performing a search on this page you should be able to see the price alert set up feature. Simply provide a valid email address and momondo will instantly alert you when prices change.

An easier way to manage your St. Louis trip

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.
Start using Trips
Find my bookings

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.
1 adult
Sun 8/31
Sun 9/7
By creating a price alert you accept our terms of use and privacy policy.

Find better results for your trip to the United States