$70 Cheap United flights Washington (IAD) to St. Louis (STL)

View $70 flight on Wed, Sep 3, 2025Opens in a new window

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$70 Cheap United flights Washington (IAD) to St. Louis (STL)

Prices were available within the past 7 days and start at $70 for one-way flights and $153 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

United
Sat, Sep 6 - Tue, Sep 9
IAD
Washington
STL
St. Louis
$153 Roundtrip, found 1 day ago
$153
Roundtrip
found 1 day ago
Select United flight, departing Sat, Sep 6 from Washington to St. Louis, returning Tue, Sep 9, priced at $153 found 1 day ago
United
Wed, Sep 3 - Thu, Sep 4
IAD
Washington
STL
St. Louis
$156 Roundtrip, found 12 hours ago
$156
Roundtrip
found 12 hours ago
Select United flight, departing Wed, Sep 3 from Washington to St. Louis, returning Thu, Sep 4, priced at $156 found 12 hours ago
United
Tue, Sep 23 - Tue, Sep 30
IAD
Washington
STL
St. Louis
$162 Roundtrip, found 1 day ago
$162
Roundtrip
found 1 day ago
Select United flight, departing Tue, Sep 23 from Washington to St. Louis, returning Tue, Sep 30, priced at $162 found 1 day ago
United
Tue, Sep 2 - Wed, Sep 3
IAD
Washington
STL
St. Louis
$166 Roundtrip, found 1 hour ago
$166
Roundtrip
found 1 hour ago
Select United flight, departing Tue, Sep 2 from Washington to St. Louis, returning Wed, Sep 3, priced at $166 found 1 hour ago
United
Wed, Sep 3 - Sat, Sep 6
IAD
Washington
STL
St. Louis
$170 Roundtrip, found 1 day ago
$170
Roundtrip
found 1 day ago
Select United flight, departing Wed, Sep 3 from Washington to St. Louis, returning Sat, Sep 6, priced at $170 found 1 day ago
United
Thu, Aug 28 - Sun, Aug 31
IAD
Washington
STL
St. Louis
$173 Roundtrip, found 1 hour ago
$173
Roundtrip
found 1 hour ago
Select United flight, departing Thu, Aug 28 from Washington to St. Louis, returning Sun, Aug 31, priced at $173 found 1 hour ago
Flights from Washington (IAD) to St. Louis (STL)
Origin airport
Washington Dulles Intl.
Destination airport
Lambert-St. Louis Intl.
Airlines serving
American Airlines, Delta, Frontier Airlines, Southwest Airlines, United
Popular airline
Delta
Distance
694 mi
Average flight time
1 hour 17 mins

Frequently asked questions

How much is a United Airlines flight from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
You'll discover budget-friendly return United Airlines flights from $153 from IAD to STL by organizing your results from "Price (lowest to highest)" on Expedia. Or search for deals from $70 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 IAD to STL with United Airlines?
Browse for return or one-way flights to St. Louis in January or February. You could find an affordable fare with United Airlines during these off-peak travel months.
What is the cheapest time to book flights from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL) with United Airlines?
To find cheap United Airlines fares from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL), start searching one to three months before your intended departure. Reserving domestic flights 34 to 86 days in advance could save you 25% compared to booking just 6 to 12 days ahead. The day you book can also impact the price you pay. Sunday is typically the most affordable, while Monday is often the most expensive for domestic flights. You can save 6% on average by booking your journey on a Sunday.**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 Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
United Airlines operates direct flights from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL), with 14 departures each week. Simply apply the "Nonstop" and "Airline" filters while searching on Expedia to show all direct United Airlines flights to STL.
How long does it take to fly from IAD to STL with United Airlines?
From takeoff till landing, a nonstop United Airlines flight from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL) takes approximately 2h 34m.
Which day of the week has the most United Airlines flights from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
If flexibility is what you're after, Thursday offers the most choice for United Airlines flights from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL). You can pick from 2 different departures.
What is the earliest United Airlines flight from IAD to STL?
Taking off from IAD at 8:50AM UTC-5, the first United Airlines flight to STL lands at 10:24AM UTC-6. Flying early means you'll be less likely to experience cancellations.* Not an early riser? The last United Airlines flight from IAD to STL departs at 5:35PM UTC-5 and touches down at 7:09PM UTC-6.*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 St. Louis?
United Airlines flights from Washington Dulles Intl. Airport (IAD) to St. Louis land at Lambert-St. Louis Intl. Airport (STL). This is the main gateway to this city.
Why fly with United Airlines from IAD to STL?
With a rewarding loyalty program, United Airlines is a top choice for many travelers heading from IAD to STL. Plus, if you're a United Mileage Plus and One Key™ member booking through Expedia, you can earn OneKeyCash™* on eligible flights along with your airline miles.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.
What type of plane does United Airlines fly from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
United Airlines generally uses Canadair (Bombardier) Regional Jet 550 planes for flights from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL). Keep in mind that aircraft type can vary depending on operational needs, so the plane you board might be different on your day of travel.
Can I change or cancel my United Airlines flight from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
Depending on your ticket type, a fee is typically charged if you modify or cancel your booking more than 24 hours after it's been confirmed. To secure plane tickets with more flexibility, select our "No cancel fee" or "Changes included" filter when you look for flights. For more details on changing or canceling your reservation, head to "Trips," select your flight and click on "Manage Booking."

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