A modern airport control tower with a spherical top and a curved, white-roofed building in the foreground.

CA $164 Cheap Flights from St. Louis (STL) to Washington (IAD)

View CA $164 flight on Mon, Sep 14, 2026Opens in a new window

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

  • Be in the know

    Get alerts if flight prices drop or rise*

  • Book smarter

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

  • Earn twice

    Earn your airline miles on top of our rewards
    Sign in

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

Prices were available within the past 7 days and start at CA $164 for one-way flights and CA $328 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Mon, Sep 14 - Thu, Sep 24
STL
St. Louis
IAD
Washington
CA $328 Roundtrip, found 3 days ago
CA $328
Roundtrip
found 3 days ago
Select Delta flight, departing Mon, Sep 14 from St. Louis to Washington, returning Thu, Sep 24, priced at CA $328 found 3 days ago
Delta
Mon, Sep 14 - Thu, Sep 24
STL
St. Louis
IAD
Washington
CA $355 Roundtrip, found 3 days ago
CA $355
Roundtrip
found 3 days ago
Select Delta flight, departing Mon, Sep 14 from St. Louis to Washington, returning Thu, Sep 24, priced at CA $355 found 3 days ago
Delta
Mon, Sep 14 - Thu, Sep 24
STL
St. Louis
IAD
Washington
CA $369 Roundtrip, found 3 days ago
CA $369
Roundtrip
found 3 days ago
Select Delta flight, departing Mon, Sep 14 from St. Louis to Washington, returning Thu, Sep 24, priced at CA $369 found 3 days ago
American Airlines
Thu, Dec 31 - Wed, Jan 6
STL
St. Louis
IAD
Washington
CA $381 Roundtrip, found 5 days ago
CA $381
Roundtrip
found 5 days ago
Select American Airlines flight, departing Thu, Dec 31 from St. Louis to Washington, returning Wed, Jan 6, priced at CA $381 found 5 days ago
Delta
Thu, Dec 31 - Wed, Jan 6
STL
St. Louis
IAD
Washington
CA $385 Roundtrip, found 5 days ago
CA $385
Roundtrip
found 5 days ago
Select Delta flight, departing Thu, Dec 31 from St. Louis to Washington, returning Wed, Jan 6, priced at CA $385 found 5 days ago
Delta
Mon, Sep 14 - Thu, Sep 24
STL
St. Louis
IAD
Washington
CA $399 Roundtrip, found 3 days ago
CA $399
Roundtrip
found 3 days ago
Select Delta flight, departing Mon, Sep 14 from St. Louis to Washington, returning Thu, Sep 24, priced at CA $399 found 3 days ago
Delta
Mon, Sep 14 - Fri, Sep 25
STL
St. Louis
IAD
Washington
CA $403 Roundtrip, found 3 days ago
CA $403
Roundtrip
found 3 days ago
Select Delta flight, departing Mon, Sep 14 from St. Louis to Washington, returning Fri, Sep 25, priced at CA $403 found 3 days ago
Delta
Mon, Sep 14 - Fri, Sep 25
STL
St. Louis
IAD
Washington
CA $419 Roundtrip, found 3 days ago
CA $419
Roundtrip
found 3 days ago
Select Delta flight, departing Mon, Sep 14 from St. Louis to Washington, returning Fri, Sep 25, priced at CA $419 found 3 days ago
United
Thu, Dec 31 - Wed, Jan 6
STL
St. Louis
IAD
Washington
CA $439 Roundtrip, found 5 days ago
CA $439
Roundtrip
found 5 days ago
Select United flight, departing Thu, Dec 31 from St. Louis to Washington, returning Wed, Jan 6, priced at CA $439 found 5 days ago
Alaska Airlines
Thu, Oct 22 - Sun, Oct 25
STL
St. Louis
IAD
Washington
CA $1,212 Roundtrip, found 1 day ago
CA $1,212
Roundtrip
found 1 day ago
Select Alaska Airlines flight, departing Thu, Oct 22 from St. Louis to Washington, returning Sun, Oct 25, priced at CA $1,212 found 1 day ago

Frequently asked questions

How much does a flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.) cost?
You can find cheap one-way flights from CA $164 and cheap return flights from CA $328 STL to IAD with Expedia. One-way flights typically cost between CA$696 and CA$1,143 and return flights often range between CA$511 and CA$1,711. Flight prices vary based on the month and day of the week you want to travel, as well as the airline and how far in advance you book your ticket. Filter your search on Expedia by "Price (lowest to highest)" to see the cheapest fares first, and use the Price Tracking tool to receive alerts when STL to IAD ticket fares go up or down.
What is the cheapest month to fly from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
The cheapest months to fly from STL to IAD are typically during off-peak season when demand is low. Traveling in off-peak or shoulder months is usually a good way to secure cheap tickets, just remember to avoid flying during holidays if you are able to. Use the calendar view in your search to see which months have low fares on this route.
Which airlines fly direct from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
Only one airline offers direct flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.). United operates 14 direct flights from STL to IAD every week.
How do I find cheap flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
To find a cheap flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.), be flexible with your dates. Traveling outside of peak vacation months and booking a mid-week flight can help you save. Early morning and late night flights are often more affordable, too. Expedia allows you to compare flight times, airlines and routes all in one place to find low fares. You can also set up Price Tracking and receive alerts when fares go up or down.
What is the best airline to fly with from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
The best airline to fly with from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.) will differ from traveler to traveler. If you like to fly early, United offers early morning flights. If price is the most important factor, United typically offers the lowest fares. United offers the most daily flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.), which is great if flexibility is what you value most. The best carrier for this journey could also be the one you have a loyalty membership with, as flying with that airline or another airline within the same alliance could help you collect points or enjoy lounge access.
What is the best time to fly from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
The best time to fly is usually mid-week (Tuesday or Wednesday) and during early morning hours as flights tend to be cheaper, less crowded, and generally more on-time. Avoid major holidays and peak vacation seasons for smoother travel. Combining off-peak days and hours often gives the best combination of cost, comfort, and convenience.
How many flights per day from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
You'll find approximately 2 nonstop flights per day from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.). For even more choices, look at flights that include layovers, as there are around 48 connecting flights per day. Some common connection points include O'Hare Intl. (ORD), Hartsfield-Jackson Atlanta Intl. (ATL), and George Bush Intercontinental (IAH).
What is the earliest flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
The earliest flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.) typically departs around 5:00 AM local time. This service is operated by American Airlines. This is a seasonal service, active in November and December. An early departure like this can help you make the most of your time at your destination. To compare early flights on Expedia, select the "Early Morning" and "Morning" filters in your search.
What day of the week has the most flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
You'll find the most flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.) on Fridays, with around 33 flights available. This gives you a good selection of options for your travel plans. Major airlines on this route include United, Delta, and American Airlines.
What are the most popular departure times for flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
The most popular departure times for flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.) are in the early morning, from 6am to 9am. Many major carriers, including United, Delta and American Airlines, offer flights during this window. Many travelers prefer these times because it allows you to arrive at your destination early, giving you a full day for business or sightseeing.
How long does it take to fly from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
A nonstop flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.) typically takes around 2 hours 18 minutes. This route covers a distance of approximately 1,118 kilometres. If you opt for a flight with one stop, your travel time will be longer, usually around 5 hours. Flights with two or more stops generally take about 9 hours. Keep in mind that actual flight times can vary due to factors like wind patterns and air traffic, so it's always a good idea to allow for some extra time when planning your trip.
Can you fly business or first class from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
Yes, you can fly business class or first class between STL and IAD. Airlines that offer business class service on this route include:
  • Frontier Airlines
  • Delta
First class cabins are available on:
  • Alaska Airlines
  • United
  • Delta
  • American Airlines
How do I earn miles on a St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.) flight with Expedia?
It's easy to earn miles on a St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.) flight when you book with Expedia. Before you confirm your booking, simply select your frequent flyer program and enter your program number. As a member of One Key™, you can also earn OneKeyCash™* on top of your airline miles when you book with Expedia.*Excludes taxes and fees. OneKeyCash is not redeemable for cash and can only be used on Expedia and other participating brands.
What airports do you fly into for Washington, DC (IAD) from St. Louis, MO (STL)?
If you're planning to travel to Washington from Lambert-St. Louis Intl. (STL), you can fly directly into Washington Dulles Intl. (IAD). Some flights may connect through major hubs like O'Hare Intl. (ORD), Philadelphia Intl. (PHL), or Eppley Field (OMA) before reaching Washington. Compare routes and airports on Expedia to find the best flight options for your travel plans.
Is it cheaper to buy a plane ticket from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.) at the last minute?
Typically, booking a last minute flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.) will be more expensive than booking in advance. As the departure date approaches, there are usually fewer seats available which can drive up the cost. However, if there's some wiggle room with your travel dates and times, you could bag a cheap last-minute fare.
Is it cheaper to book a St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.) flight and hotel package?
Securing a St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.) flight and hotel package is usually cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels all in one place. Select from our extensive range of stays and then add flights, activities and car rentals to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
If you booked your St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.) flight within the last 24 hours, you may be able to modify or cancel it without any fees. Depending on the airline and the type of ticket you have, additional charges may apply for changes beyond this timeframe. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal if you'd like more information.

Travel information

Origin airport
Lambert-St. Louis Intl.
Destination airport
Washington Dulles Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta
Roundtrip price
CA $328
Distance
1111 km
Average flight time
3 hours 10 mins

Book with confidence

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 20 airlines that cover this route. There are 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 $328 rising to CA $1,212.  

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.

St. Louis to Chantilly Flights

Explore a world of travel with Expedia

*Available to Expedia members.