CA $186 Cheap Flights from Washington (IAD) to St. Louis (STL)

View CA $186 flight on Mon, Sep. 29, 2025Opens in a new window

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

  • Plan, book, fly with confidence

  • trending down icon

    Be in the know

    Get alerts if flight prices drop or rise*
  • bex rewards loyalty icon

    Book smarter

    Save up to 30% on select hotels after you book a flight*
  • payments icon

    Earn twice

    Earn your airline miles on top of our rewards
    Sign in

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

Prices were available within the past 7 days and start at CA $186 for one-way flights and CA $322 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Tue, Sep. 9 - Tue, Sep. 23
IAD
Washington
STL
St. Louis
CA $322 Roundtrip, found 3 days ago
CA $322
Roundtrip
found 3 days ago
Select Delta flight, departing Tue, Sep. 9 from Washington to St. Louis, returning Tue, Sep. 23, priced at CA $322 found 3 days ago
Delta
Tue, Sep. 9 - Mon, Sep. 22
IAD
Washington
STL
St. Louis
CA $346 Roundtrip, found 3 days ago
CA $346
Roundtrip
found 3 days ago
Select Delta flight, departing Tue, Sep. 9 from Washington to St. Louis, returning Mon, Sep. 22, priced at CA $346 found 3 days ago
Delta
Sun, Aug. 31 - Sat, Sep. 13
IAD
Washington
STL
St. Louis
CA $347 Roundtrip, found 3 days ago
CA $347
Roundtrip
found 3 days ago
Select Delta flight, departing Sun, Aug. 31 from Washington to St. Louis, returning Sat, Sep. 13, priced at CA $347 found 3 days ago
Delta
Tue, Sep. 2 - Sat, Sep. 13
IAD
Washington
STL
St. Louis
CA $367 Roundtrip, found 3 days ago
CA $367
Roundtrip
found 3 days ago
Select Delta flight, departing Tue, Sep. 2 from Washington to St. Louis, returning Sat, Sep. 13, priced at CA $367 found 3 days ago
Delta
Thu, Sep. 11 - Mon, Sep. 22
IAD
Washington
STL
St. Louis
CA $368 Roundtrip, found 3 days ago
CA $368
Roundtrip
found 3 days ago
Select Delta flight, departing Thu, Sep. 11 from Washington to St. Louis, returning Mon, Sep. 22, priced at CA $368 found 3 days ago
Delta
Sun, Aug. 31 - Thu, Sep. 18
IAD
Washington
STL
St. Louis
CA $371 Roundtrip, found 3 days ago
CA $371
Roundtrip
found 3 days ago
Select Delta flight, departing Sun, Aug. 31 from Washington to St. Louis, returning Thu, Sep. 18, priced at CA $371 found 3 days ago
Delta
Fri, Sep. 5 - Tue, Sep. 23
IAD
Washington
STL
St. Louis
CA $391 Roundtrip, found 3 days ago
CA $391
Roundtrip
found 3 days ago
Select Delta flight, departing Fri, Sep. 5 from Washington to St. Louis, returning Tue, Sep. 23, priced at CA $391 found 3 days ago
Delta
Wed, Aug. 20 - Wed, Sep. 3
IAD
Washington
STL
St. Louis
CA $403 Roundtrip, found 3 days ago
CA $403
Roundtrip
found 3 days ago
Select Delta flight, departing Wed, Aug. 20 from Washington to St. Louis, returning Wed, Sep. 3, priced at CA $403 found 3 days ago
United
Wed, Aug. 27 - Sat, Sep. 6
IAD
Washington
STL
St. Louis
CA $405 Roundtrip, found 3 days ago
CA $405
Roundtrip
found 3 days ago
Select United flight, departing Wed, Aug. 27 from Washington to St. Louis, returning Sat, Sep. 6, priced at CA $405 found 3 days ago
American Airlines
Thu, Aug. 28 - Sat, Sep. 6
IAD
Washington
STL
St. Louis
CA $464 Roundtrip, found 3 days ago
CA $464
Roundtrip
found 3 days ago
Select American Airlines flight, departing Thu, Aug. 28 from Washington to St. Louis, returning Sat, Sep. 6, priced at CA $464 found 3 days ago

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

March is typically the cheapest month to fly

From CA $220 - CA $705 per traveller.

Graph displaying average flight prices per month

Flight from Washington to St. Louis (IAD - STL) route information
Origin airport
Washington Dulles Intl.
Destination airport
Lambert-St. Louis Intl.
Airlines serving
American Airlines, Delta, United
Roundtrip price
CA $322
Distance
1111 km
Average flight time
1 hour 20 mins

Chantilly to St. Louis Flights

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

With Expedia, it’s simple to find and book flights to St. Louis from Washington whether you’re traveling for business or pleasure. Enter your travel dates, hit search, and choose your flight from 20 airlines that cover this route. There are Avianca, Copa Airlines, Brussels Airlines, Lufthansa, United Airlines nonstop flights to Lambert-St. Louis 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 Washington to St. Louis today, tomorrow, or this week.  

 

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

Sort your search results by price to find great deals on your flight from Washington to St. Louis—you get all your cheapest options first. Grab yourself a bargain now—the lowest price on flights to St. Louis from Washington currently is just CA $322 rising to CA $464.  

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 St. Louis  
  • 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 St. Louis from Washington 

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 St. Louis with Expedia today.

Frequently asked questions

How much is a flight from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
Within the past 7 days on Expedia, for flights departing within the next year, the lowest price advertised for a round-trip journey between IAD and Lambert-St. Louis Intl. Airport (STL) was CA $322. Cheap fares don't last long, so make sure you book yours ASAP. Prices and availability are subject to change. Additional terms apply.
Do I need to pay a cancellation fee if I cancel my flight from IAD to Lambert Field?
Every airline has its own set of terms and conditions. If you decide to cancel your vacation, head to our Customer Service Portal.
How do I find cheap flights from IAD to STL that have flexible change policies?
Select our "No change fees" filter to find flexible ticketing options for your flight from Washington Dulles Intl. Airport (IAD) to STL. This allows you to lock in a good price in advance and still have the freedom to make changes without any additional fees. You'll just need to pay the difference in fare.
How many hours is the flight from Washington Dulles Intl. Airport (IAD) to Lambert Field?
It takes around 7 hours and 7 minutes to journey from Dulles Intl. Airport to STL — just enough time for a short snooze. You'll be starting your descent into St. Louis by the time you open your eyes.
How far is the flight from Dulles Intl. Airport to STL?
With a flight distance of 1,100 kilometres, it's only a short hop from IAD to Lambert Field. It might be a quick flight, but it's still worth bringing something to keep you busy on board.
Which airlines fly direct from Washington Dulles Intl. Airport (IAD) to STL?
Flying directly from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL) is a cinch with United Airlines (UA). This top carrier offers 60 flights each month.
Are Washington Dulles Intl. Airport (IAD) to STL flight tickets cheaper when they're purchased at the last minute?
Last-minute planners can occasionally pick up a bargain, with some super cheap fares from IAD to Lambert Field popping up a few weeks prior to the departure date. If you'd rather book ahead of time, Expedia compares and updates all the best flight deals continuously — as early as 12 months in advance in some cases. It does depend on the carrier though, as not all airlines issue prices so far in advance.

Explore a world of travel with Expedia

*Available to Expedia members.