$72 Cheap United flights from St. Louis to Washington (STL to IAD)

Find The Best Day To Fly from St. Louis to Washington

Amazing United STL to IAD Flight Deals

The cheapest flights to Washington Dulles Intl. found within the past 7 days were $193 round trip and $72 one way. Prices and availability subject to change. Additional terms may apply.

Fri, Oct 31 - Sun, Nov 2
STL
St. Louis
IAD
Washington
$193 Roundtrip, found 1 day ago
$193
Roundtrip
found 1 day ago
Select United flight, departing Fri, Oct 31 from St. Louis to Washington, returning Sun, Nov 2, priced at $193 found 1 day ago
Thu, Oct 2 - Sat, Oct 4
STL
St. Louis
IAD
Washington
$196 Roundtrip, found 13 hours ago
$196
Roundtrip
found 13 hours ago
Select United flight, departing Thu, Oct 2 from St. Louis to Washington, returning Sat, Oct 4, priced at $196 found 13 hours ago
Tue, Aug 26 - Sat, Sep 27
STL
St. Louis
IAD
Washington
$210 Roundtrip, found 1 day ago
$210
Roundtrip
found 1 day ago
Select United flight, departing Tue, Aug 26 from St. Louis to Washington, returning Sat, Sep 27, priced at $210 found 1 day ago
Sun, Oct 12 - Fri, Oct 17
STL
St. Louis
IAD
Washington
$211 Roundtrip, found 9 hours ago
$211
Roundtrip
found 9 hours ago
Select United flight, departing Sun, Oct 12 from St. Louis to Washington, returning Fri, Oct 17, priced at $211 found 9 hours ago
Tue, Aug 26 - Sat, Sep 27
STL
St. Louis
IAD
Washington
$217 Roundtrip, found 1 day ago
$217
Roundtrip
found 1 day ago
Select United flight, departing Tue, Aug 26 from St. Louis to Washington, returning Sat, Sep 27, priced at $217 found 1 day ago
Wed, Sep 3 - Thu, Sep 4
STL
St. Louis
IAD
Washington
$217 Roundtrip, found 3 days ago
$217
Roundtrip
found 3 days ago
Select United flight, departing Wed, Sep 3 from St. Louis to Washington, returning Thu, Sep 4, priced at $217 found 3 days ago

IAD From STL Economy Coach Packages on Similar Airlines

Price found within the past 48 hours. Click for updated prices.
Omni Shoreham Hotel

Omni Shoreham Hotel

4 out of 5
Save 100% on your flight
per person
Oct 23 - Oct 27
found 10 hours ago
Roundtrip flight included
St. Louis (STL) to Washington (DCA)
The St. Gregory Hotel

The St. Gregory Hotel

4 out of 5
Save 100% on your flight
per person
Oct 23 - Oct 27
found 10 hours ago
Roundtrip flight included
St. Louis (STL) to Washington (DCA)
SIXTY DC

SIXTY DC

2 out of 5
Save 100% on your flight
per person
Oct 23 - Oct 27
found 10 hours ago
Roundtrip flight included
St. Louis (STL) to Washington (DCA)
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Frequently asked questions

Can I catch a flight from St. Louis Lambert International Airport to Washington Dulles Intl. Airport (IAD) right now?
Make sure you visit our Covid-19 Travel Advisor to find out if there are any current travel advice reports and quarantine requirements in effect in IAD when flying from St. Louis Lambert International Airport.
What terminal is United Airlines at St. Louis Lambert International Airport?
Flights normally leave from terminal 1 at St. Louis Lambert International Airport if you've booked a ticket with United Airlines. Landing at Washington Dulles Intl. Airport (IAD)? Contact your airline (or do some online research) to find out exactly which terminal you'll be pulling into.
Are there United Airlines non-stop flights from STL to IAD?
Yes. Book a nonstop flight with United Airlines from St. Louis Lambert International Airport to Washington Dulles Intl. Airport (IAD), and you won't have to worry about stopovers or trying to run for your connecting flight.
How long is a United Airlines flight from STL to IAD?
Bad weather, tailwinds, headwinds ... They're just a few factors that can influence how long your time in the air will last. However, a flight from St. Louis Lambert International Airport to Dulles Intl. Airport with United Airlines takes roughly 2 hours and 45 minutes, so you'll have landed and be in getaway mode in next to no time.
What type of aircraft does United Airlines fly from STL to IAD?
Booked a flight with United Airlines between STL and IAD? The Embraer ERJ and the Canadair (Bombardier) Regional Jet 550 are the two types of aircraft that normally operate on this route.
How many direct and indirect flights does United Airlines fly from STL to IAD?
You can take your pick of about 3 flights every day with United Airlines from St. Louis Lambert International Airport to Washington Dulles Intl. Airport (IAD).
If I am not able to travel due to COVID-19, can I change my booking to a later date?
For more info about changing your flight to IAD, please visit our Customer Service Portal.
What is the best day to buy a plane ticket?
This just in! Airfares offered on Thursdays tend to be the cheapest, according to flight demand on Travelocity in 2021. Tuesday and Wednesday prices are also good, but you may want to prepare your budget if booking during the weekend, as data shows that is when prices are generally at their highest.
What are the cheapest days to fly?
Frequent travelers may already know this, but earlier in the week can be the cheapest time to fly. In 2021, flights departing on a Monday were generally the cheapest of the week, whereas you may pay a premium for weekend flights when demand is usually high. On average, tickets were most expensive for Saturday departures, so if you need to fly out on a weekend, you might look for deals ahead of time.
How far in advance can you book a flight?
Trying to figure out how early you should book your flight? It's possible to start comparing international airfares on Travelocity up to 12 months in advance. However, it does depend on the carrier as not all airlines release their prices that far out. According to our 2021 flight demand trends, last minute planners can still bag a bargain with some of the cheapest fares appearing 0-2 weeks prior to their travel dates.*According to flight demand on Travelocity.com from January to December 2021. Savings are subject to change based on departure location, date and destination.

Discover our best United flight from St. Louis STL to Washington IAD 

To find the best deals on flights to St. Louis from Washington with United, just enter your travel dates, filter by United, and hit search. You’ll find flights to choose from and can sort by price, flight duration, and arrival or departure time.  

 

Return flights from St. Louis STL to Washington IAD with United 

If you’re planning a round trip, booking return flights with United is usually the most cost-effective option. With airfares ranging from $193 to $217, it’s easy to find a flight that suits your budget. Prices and availability subject to change. Additional terms may apply. 

 

Book one-way United flights from St. Louis STL to Washington IAD 

A one-way ticket gives you much greater flexibility—allowing you to choose your return date, destination, and time whenever you’re ready. By booking in advance you can find great deals on one-way tickets too. Right now, a one-way United flight from St. Louis to Washington costs from $72. Prices and availability subject to change. Additional terms may apply. 

 

The easy way to find cheap flights to Washington IAD from  St. Louis STL with United 

To find a cheap United flight from St. Louis STL to Washington IAD, sort your search results by price or filter by budget. Thanks to Travelocity’s Price Match Promise, if you find a better airfare deal anywhere else within 24 hours, we’ll credit or refund the difference. 

 

How to find our best airfare deals on United flights from St. Louis STL to Washington IAD 

If you’re looking for cheap flights, it helps to be flexible when it comes to your travel dates. You’ll usually find lower cost tickets when you travel during quieter months such as October, or if you book a flight with a stopover. 

 

Find nonstop flights from St. Louis STL to Washington IAD with United 

If you’re keen to be on Washington soil fast, don’t waste time with a stopover—filter your search results to show direct United flights only. The journey takes around hour(s) min(s) – so you’ll be there before you know it. 

 

Flexible airline tickets for United flights from St. Louis STL to Washington IAD 

Make sure you’re not out of pocket if plans change by choosing a flexible ticket with penalty-free amendment and cancellation options. Use our ‘no change fee’ filter to see which flights have this option.  

 

There are a lot of reasons to book your flights to Washington IAD from  St. Louis STL with United on Travelocity 

At Travelocity our vast and up-to-the-minute inventory puts all of our best flight deals in one place. So, whether you’re traveling on business or jetting off with friends and family, you can trust Travelocity to get you there.

United Airports
Hop on a(n) United flight today by flying to many destinations out of these domestic and international airports:
Airport code
Country
Airport name
Number of flights
ORDUSAO'Hare Intl.227
DENUSADenver Intl.226
IAHUSAGeorge Bush Intercontinental136
IADUSAWashington Dulles Intl.100
SFOUSASan Francisco Intl.64
LAXUSALos Angeles Intl.23
EWRUSALiberty Intl.20
FRADEUFrankfurt Intl.19
NRTJPNNarita Intl.19
PEKCHNCapital Intl.16

Travelers ❤️ these 🏨 after their flight to Washington

Hyatt Regency Dulles

Hyatt Regency Dulles

4 out of 5
2300 Dulles Corner Blvd, Herndon, VA
This hotel features an indoor pool, A 24-hour gym, and a restaurant. Traveling on business? Take advantage of the 24-hour business center, free WiFi in public ...
8.8/10 Excellent! (1,388 reviews)
"This was an overnight after a long flight. Near the airport and easy access to the road home (our car had been parked there during our trip)."

Reviewed on Aug 4, 2025

Hyatt Regency Dulles
Hyatt Place Herndon Dulles Airport East

Hyatt Place Herndon Dulles Airport East

3 out of 5
13711 Sayward Blvd, Herndon, VA
This hotel features a restaurant, an indoor pool, and a bar/lounge. Traveling on business? Take advantage of the free WiFi in public areas, express check-out, ...
8.2/10 Very Good! (2,373 reviews)
"Lobby are not as such convenient."

Reviewed on Aug 5, 2025

Hyatt Place Herndon Dulles Airport East
The Westin Washington Dulles Airport

The Westin Washington Dulles Airport

4 out of 5
2520 Wasser Terrace, Herndon, VA
This hotel features a restaurant, a 24-hour gym, and a bar/lounge. Traveling on business? Take advantage of the 24-hour business center, free WiFi in public ...
8.6/10 Excellent! (1,006 reviews)
"Went for a weekend girls trip although an event was taken place staff were friendly and location was great. Clean rooms and all staff were accommodating. I would definitely recommend this location."

Reviewed on Aug 4, 2025

The Westin Washington Dulles Airport
Lowest nightly price found within the past 24 hours based on a 1 night stay for 2 adults. Prices and availability subject to change. Additional terms may apply.
*Price based on the lowest price found within past 24 hours and based upon one night stay for two adults over the next thirty days. Prices and availability subject to change. Additional terms may apply.