$139 Cheap United flights St. Louis (STL) to Boston (BOS)

View $139 flight on Mon, Aug 4, 2025Opens in a new window

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$139 Cheap United flights St. Louis (STL) to Boston (BOS)

Prices were available within the past 7 days and start at $139 for one-way flights and $277 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

United
Thu, Sep 4 - Thu, Sep 11
STL
St. Louis
BOS
Boston
$277 Roundtrip, found 1 hour ago
$277
Roundtrip
found 1 hour ago
Select United flight, departing Thu, Sep 4 from St. Louis to Boston, returning Thu, Sep 11, priced at $277 found 1 hour ago
Flights from St. Louis (STL) to Boston (BOS)
Origin airport
Lambert-St. Louis Intl.
Destination airport
Logan Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Southwest Airlines, Spirit Airlines, United
Popular airline
American Airlines
Distance
1043 mi
Average flight time
3 hours 50 mins

Frequently asked questions

How much is a United Airlines flight from Lambert-St. Louis Intl. Airport (STL) to Logan Intl. Airport (BOS)?
You can discover budget-friendly return United Airlines flights from $277 from STL to BOS by organizing your results from "Price (lowest to highest)" on Expedia. Or search for deals from $139 for a one-way journey.**These prices were available on Expedia within the past 7 days, for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.
What is the cheapest month to fly from STL to BOS with United Airlines?
Look for round-trip or one-way flights to Boston in January or February. You could find cheaper fares with United Airlines during these quieter months.
What is the cheapest time to book flights from Lambert-St. Louis Intl. Airport (STL) to Logan Intl. Airport (BOS) with United Airlines?
Search for affordable United Airlines flights from Lambert-St. Louis Intl. Airport (STL) to Logan Intl. Airport (BOS) one to three months prior to your day of departure. Travelers who book domestic flights 34 to 86 days in advance can save 25% compared to those who book just 6 to 12 days ahead. Regardless of fare class and journey, the best day to book a domestic flight is usually Sunday and the most expensive is typically Monday. Passengers who book on a Sunday can save 6% on average compared to those who book their travel on a Monday.**Ideal booking window recommendation is based on average round-trip ticket prices for January through November for 2024. Best day of the week to book recommendation is based on average round-trip ticket prices for January through October 2024. All data sourced from ARC's global airline sales database.
Does United Airlines fly nonstop from Lambert-St. Louis Intl. Airport (STL) to Logan Intl. Airport (BOS)?
Use our "Nonstop" filter when looking for direct United Airlines flights from STL to BOS. You'll also be able to compare other airlines servicing the same direct trip.
What is the earliest United Airlines flight from STL to BOS?
Search United Airlines's earliest flights from STL to BOS by selecting our "Early Morning" and "Morning" filters. Not only will you get to where you're going sooner, early departures also have a 20% less chance of being canceled.**Most reliable time of the day recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports does United Airlines fly into in Boston?
Get on a United Airlines flight from Lambert-St. Louis Intl. Airport (STL) to Boston, and you'll probably come in to Logan Intl. Airport (BOS). This is the airline's primary hub in this city.
Why fly with United Airlines from STL to BOS?
Travel from STL to BOS with United Airlines and look forward to a range of perks including a rewarding loyalty program. When you book through Expedia as a United Mileage Plus and One Key™ member, you could also earn OneKeyCash™* to redeem on select future travel purchases.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.
Can I change or cancel my United Airlines flight from Lambert-St. Louis Intl. Airport (STL) to Logan Intl. Airport (BOS)?
Depending on your fare type, a fee may apply if you cancel or reschedule your flight more than 24 hours after it's been confirmed. To find flexible plane tickets, select our "Changes included" and "No cancel fee" boxes while looking for flights. To learn more about modifying or canceling your reservation, go to "Trips," select your flight and click on "Manage Booking."

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