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CA $178 Cheap Flights from Washington (IAD) to St. Louis (STL)

View CA $178 flight on Thu, Sep 17, 2026Opens in a new window

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

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

Prices were available within the past 7 days and start at CA $178 for one-way flights and CA $385 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Wed, Oct 7 - Fri, Oct 9
IAD
Washington
STL
St. Louis
CA $385 Roundtrip, found 8 hours ago
CA $385
Roundtrip
found 8 hours ago
Select Delta flight, departing Wed, Oct 7 from Washington to St. Louis, returning Fri, Oct 9, priced at CA $385 found 8 hours ago
Delta
Wed, Oct 7 - Fri, Oct 9
IAD
Washington
STL
St. Louis
CA $427 Roundtrip, found 8 hours ago
CA $427
Roundtrip
found 8 hours ago
Select Delta flight, departing Wed, Oct 7 from Washington to St. Louis, returning Fri, Oct 9, priced at CA $427 found 8 hours ago
American Airlines
Thu, Sep 17 - Sun, Sep 20
IAD
Washington
STL
St. Louis
CA $459 Roundtrip, found 6 days ago
CA $459
Roundtrip
found 6 days ago
Select American Airlines flight, departing Thu, Sep 17 from Washington to St. Louis, returning Sun, Sep 20, priced at CA $459 found 6 days ago
Delta
Thu, Sep 17 - Sun, Sep 20
IAD
Washington
STL
St. Louis
CA $485 Roundtrip, found 6 days ago
CA $485
Roundtrip
found 6 days ago
Select Delta flight, departing Thu, Sep 17 from Washington to St. Louis, returning Sun, Sep 20, priced at CA $485 found 6 days ago
American Airlines
Wed, Oct 7 - Fri, Oct 9
IAD
Washington
STL
St. Louis
CA $510 Roundtrip, found 8 hours ago
CA $510
Roundtrip
found 8 hours ago
Select American Airlines flight, departing Wed, Oct 7 from Washington to St. Louis, returning Fri, Oct 9, priced at CA $510 found 8 hours ago
Delta
Thu, Sep 17 - Sun, Sep 20
IAD
Washington
STL
St. Louis
CA $529 Roundtrip, found 6 days ago
CA $529
Roundtrip
found 6 days ago
Select Delta flight, departing Thu, Sep 17 from Washington to St. Louis, returning Sun, Sep 20, priced at CA $529 found 6 days ago
Delta
Thu, Sep 17 - Sun, Sep 20
IAD
Washington
STL
St. Louis
CA $546 Roundtrip, found 6 days ago
CA $546
Roundtrip
found 6 days ago
Select Delta flight, departing Thu, Sep 17 from Washington to St. Louis, returning Sun, Sep 20, priced at CA $546 found 6 days ago
Delta
Thu, Sep 17 - Sun, Sep 20
IAD
Washington
STL
St. Louis
CA $555 Roundtrip, found 6 days ago
CA $555
Roundtrip
found 6 days ago
Select Delta flight, departing Thu, Sep 17 from Washington to St. Louis, returning Sun, Sep 20, priced at CA $555 found 6 days ago
Delta
Wed, Oct 7 - Fri, Oct 9
IAD
Washington
STL
St. Louis
CA $581 Roundtrip, found 8 hours ago
CA $581
Roundtrip
found 8 hours ago
Select Delta flight, departing Wed, Oct 7 from Washington to St. Louis, returning Fri, Oct 9, priced at CA $581 found 8 hours ago
Alaska Airlines
Wed, Oct 7 - Fri, Oct 9
IAD
Washington
STL
St. Louis
CA $1,186 Roundtrip, found 8 hours ago
CA $1,186
Roundtrip
found 8 hours ago
Select Alaska Airlines flight, departing Wed, Oct 7 from Washington to St. Louis, returning Fri, Oct 9, priced at CA $1,186 found 8 hours ago

Frequently asked questions

How much does a flight from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) cost?
You can find cheap one-way flights from CA $178 and cheap return flights from CA $385 IAD to STL with Expedia. Return flights often range between CA$607 and CA$1516. 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 IAD to STL ticket fares go up or down.
What is the cheapest month to fly from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
September is typically the cheapest month to fly from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.), with average return fares around CA$421. September often sees lower prices as the summer travel rush ends and before the holiday season begins, leading to reduced demand. Other cheap months to fly from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) include February and August.
Which airlines fly direct from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
Only one airline offers direct flights from Washington Dulles Intl. (IAD) to Lambert-St. Louis Intl. (STL).United operates 17 direct flights from Washington Dulles Intl. to Lambert-St. Louis Intl. every week.
What is the cheapest airline that flies from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
United is one of the cheapest airlines offering nonstop return flights from Washington Dulles Intl. (IAD) to Lambert-St. Louis Intl. (STL), with tickets starting from around CA$664 for flights that can be booked for departure within the next year. Alaska Airlines offers one of the cheapest connecting return flights from Washington Dulles Intl. (IAD) to Lambert-St. Louis Intl. (STL) starting from around CA$683. These prices are per adult for economy/coach class. Use Expedia's search tool to compare the prices and schedules of airlines that fly this route to find the best option for your plans and budget.
How do I find cheap flights from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
To find a cheap flight from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis 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 Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
The best airline to fly with from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis 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 Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis 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 Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
The cheapest months to fly from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) are typically September and February, with average return flights around CA$421. May is a popular month for this route, meaning you'll find plenty of flight options, though prices might be a bit higher. If you're looking for the best value, aiming for September or February could save you money, while May offers more flexibility in flight times.
How many flights per day from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
You'll find approximately 2 nonstop flights per day from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.). For even more choices, look at flights that include layovers, as there are around 43 connecting flights per day. Some common connection points include O'Hare Intl. (ORD), Hartsfield-Jackson Atlanta Intl. (ATL), and Charlotte-Douglas Intl. (CLT).
What is the earliest flight from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
The earliest flight from Washington Dulles Intl. (IAD) to Lambert-St. Louis Intl. (STL) typically departs around 5:00 AM local time. This flight is operated by American Airlines. This is a seasonal service active in February and March. 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 Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
You'll typically find the most flights from Washington Dulles Intl. (IAD) to Lambert-St. Louis Intl. (STL) on a Thursday, with around 27 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. Flight schedules are fairly consistent throughout the week, so you'll have plenty of options no matter which day you choose to fly.
What are the most popular departure times for flights from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
The most popular departure times for flights from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis 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 travellers prefer these early flights to get a head start on their day at their destination.
How long does it take to fly from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
When flying from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.), you have a few options. A nonstop flight typically takes around 2 hours 30 minutes, covering a distance of approximately 1,118 kilometers. If you opt for a one-stop flight, your travel time will be longer, usually around 4 hours 48 minutes. Flights with two or more stops will take even more time, generally about 9 hours 30 minutes. 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 Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
Yes, you can fly business class or first class between IAD and STL. 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 Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) flight with Expedia?
It's easy to earn miles on a Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis 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 St. Louis, MO (STL) from Washington, DC (IAD)?
If you're planning to travel to St. Louis from Washington Dulles Intl. (IAD), you can fly directly into Lambert-St. Louis Intl. (STL). Some flights may connect through major hubs like Denver Intl. (DEN), Detroit Metropolitan Wayne County (DTW), or Charlotte-Douglas Intl. (CLT) before reaching St. Louis. 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 Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) at the last minute?
Typically, booking a last minute flight from Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis 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 Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.) flight and hotel package?
Securing a Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis 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 Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis Intl.)?
If you booked your Washington, DC (IAD-Washington Dulles Intl.) to St. Louis, MO (STL-Lambert-St. Louis 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
Washington Dulles Intl.
Destination airport
Lambert-St. Louis Intl.
Roundtrip price
CA $385
Distance
1111 km
Average flight time
1 hour 20 mins

Book with confidence

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 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 $385 rising to CA $1,186.  

Here are more money-saving tips: 

  • Fly in October 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.

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