CA $136 Cheap Flights from St. Louis (STL) to Washington (IAD)

View CA $136 flight on Tue, Sep. 30, 2025Opens in a new window

Popular airlines from Lambert-St. Louis International Airport (STL) to Washington Dulles International Airport (IAD)

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

Prices were available within the past 7 days and start at CA $136 for one-way flights and CA $272 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Tue, Sep. 30 - Fri, Oct. 3
STL
St. Louis
IAD
Washington
CA $272 Roundtrip, found 6 days ago
CA $272
Roundtrip
found 6 days ago
Select Delta flight, departing Tue, Sep. 30 from St. Louis to Washington, returning Fri, Oct. 3, priced at CA $272 found 6 days ago
American Airlines
Tue, Sep. 30 - Fri, Oct. 3
STL
St. Louis
IAD
Washington
CA $326 Roundtrip, found 6 days ago
CA $326
Roundtrip
found 6 days ago
Select American Airlines flight, departing Tue, Sep. 30 from St. Louis to Washington, returning Fri, Oct. 3, priced at CA $326 found 6 days ago
Delta
Tue, Sep. 30 - Fri, Oct. 3
STL
St. Louis
IAD
Washington
CA $327 Roundtrip, found 6 days ago
CA $327
Roundtrip
found 6 days ago
Select Delta flight, departing Tue, Sep. 30 from St. Louis to Washington, returning Fri, Oct. 3, priced at CA $327 found 6 days ago
Delta
Tue, Sep. 30 - Fri, Oct. 3
STL
St. Louis
IAD
Washington
CA $367 Roundtrip, found 6 days ago
CA $367
Roundtrip
found 6 days ago
Select Delta flight, departing Tue, Sep. 30 from St. Louis to Washington, returning Fri, Oct. 3, priced at CA $367 found 6 days ago

Find the cheapest month to fly from St. Louis (STL) to Washington (IAD)

February is typically the cheapest month to fly

From CA $206 - CA $831 per traveller.

Graph displaying average flight prices per month

Flight from St. Louis to Washington (STL - IAD) route information
Origin airport
Lambert-St. Louis Intl.
Destination airport
Washington Dulles Intl.
Roundtrip price
CA $271
Distance
1111 km
Average flight time
3 hours 8 mins

St. Louis to Chantilly Flights

The easy way to book your flights from St. Louis to Washington 

With Expedia, it’s simple to find and book flights to Washington from St. Louis whether you’re traveling for business or pleasure. Enter your travel dates, hit search, and choose your flight from 7 airlines that cover this route. There are Avianca, Copa Airlines, Brussels Airlines, Lufthansa, United Airlines nonstop flights to Washington Dulles Intl., too.  

Choose your preferred carrier and cabin class with the advanced search tool and select your ideal departure time. Then, if you want, you can see just nonstop or refundable flights. And if you’re traveling last minute, just enter the date to check out flights from St. Louis to Washington today, tomorrow, or this week.  

 

Save dollars with cheap flights from Lambert-St. Louis Intl., STL to Washington Dulles Intl., IAD 

Sort your search results by price to find great deals on your flight from St. Louis to Washington—you get all your cheapest options first. Grab yourself a bargain now—the lowest price on flights to Washington from St. Louis currently is just CA $272 rising to CA $367.  

Here are more money-saving tips: 

  • Fly in September when flight prices are normally at their lowest 
  • Book about a month to 6 weeks before you travel for the best prices to Washington  
  • Avoid peak season and weekends when flights can cost more
  • Early morning and late-night flights are sometimes cheaper, so try varying your travel times 
  • One surefire way to save money on your flight is to book your flight and hotel together with Expedia. Sometimes, the savings are so large that the flight is basically free! 

 

Reasons to choose Expedia for your flight to Washington from St. Louis 

Whatever your destination, budget, or reason to travel, in just one quick search, you can choose from loads of flights, airlines, and cabin classes. The filters make it quick and easy to find your ideal flights, and if you choose one of the flexible options, you won’t be charged to change your flight. So book your flight to Washington with Expedia today.

Frequently asked questions

How much is a flight from Lambert Field to Dulles Intl. Airport?
Pack your bags, because round-trip journeys from STL to Washington Dulles Intl. Airport (IAD) start from CA $272. That's based on airfares listed within the last 7 days on Expedia for flights departing within the next year. Prices can change quickly, so book now to nab the best deal. Prices and availability are subject to change. Additional terms apply.
Do I need to pay a cancellation fee if I cancel my flight from Lambert Field to Washington Dulles Intl. Airport (IAD)?
Every airline has its own terms and conditions. If you decide to cancel your trip, visit our Customer Service Portal.
How do I find cheap flights from STL to IAD that have flexible change policies?
Many carriers offer the option to move your flight without charging a fee. All you pay is the cost difference between the two flights. When looking for Lambert-St. Louis Intl. Airport (STL) to Dulles Intl. Airport flights, you'll see a "No change fees" filter for you to select.
How many hours is the flight from Lambert-St. Louis Intl. Airport (STL) to Dulles Intl. Airport?
The flight time from Lambert-St. Louis Intl. Airport (STL) to IAD is a comfortable 6 hours and 47 minutes. You'll be lucky to get through an in-flight movie before arriving!
How far is the flight from STL to Washington Dulles Intl. Airport (IAD)?
It's just 1,100 kilometres between St. Louis and Chantilly. It's quite possible that you'll spend more time travelling to and from the airport than you will actually flying!
Which airlines fly direct from STL to Washington Dulles Intl. Airport (IAD)?
Flying nonstop from STL to IAD is simple with United Airlines (UA). This top airline offers 60 flights every month.
Are Lambert Field to Dulles Intl. Airport flight tickets cheaper when they're purchased at the last minute?
Late planners can occasionally pick up a bargain, with some of the cheapest fares from Lambert Field to Dulles Intl. Airport appearing a few weeks before the departure date. If you'd rather plan ahead, Expedia compares and updates all the best flight deals continuously — as early as 12 months in advance in some cases. It depends on the carrier though, as not all airlines release prices that far in advance.

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