£237 Cheap Flights from St. Louis (STL) to Washington (IAD)

View £237 flight on Mon, 8 Jun 2026Opens 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 £237 for one-way flights and £553 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Alaska Airlines
Wed, 20 May - Wed, 27 May
STL
St. Louis
IAD
Washington
£553 Return, found 16 hours ago
£553
Return
found 16 hours ago
Select Alaska Airlines flight, departing Wed, 20 May from St. Louis to Washington, returning Wed, 27 May, priced at £553 found 16 hours ago
Alaska Airlines
Wed, 20 May - Wed, 27 May
STL
St. Louis
IAD
Washington
£623 Return, found 16 hours ago
£623
Return
found 16 hours ago
Select Alaska Airlines flight, departing Wed, 20 May from St. Louis to Washington, returning Wed, 27 May, priced at £623 found 16 hours ago
Alaska Airlines
Wed, 20 May - Wed, 27 May
STL
St. Louis
IAD
Washington
£627 Return, found 16 hours ago
£627
Return
found 16 hours ago
Select Alaska Airlines flight, departing Wed, 20 May from St. Louis to Washington, returning Wed, 27 May, priced at £627 found 16 hours ago
Alaska Airlines
Wed, 20 May - Wed, 27 May
STL
St. Louis
IAD
Washington
£632 Return, found 16 hours ago
£632
Return
found 16 hours ago
Select Alaska Airlines flight, departing Wed, 20 May from St. Louis to Washington, returning Wed, 27 May, priced at £632 found 16 hours ago
Alaska Airlines
Wed, 20 May - Wed, 27 May
STL
St. Louis
IAD
Washington
£632 Return, found 16 hours ago
£632
Return
found 16 hours ago
Select Alaska Airlines flight, departing Wed, 20 May from St. Louis to Washington, returning Wed, 27 May, priced at £632 found 16 hours ago
Alaska Airlines
Wed, 20 May - Wed, 27 May
STL
St. Louis
IAD
Washington
£636 Return, found 16 hours ago
£636
Return
found 16 hours ago
Select Alaska Airlines flight, departing Wed, 20 May from St. Louis to Washington, returning Wed, 27 May, priced at £636 found 16 hours ago
Alaska Airlines
Wed, 20 May - Wed, 27 May
STL
St. Louis
IAD
Washington
£640 Return, found 16 hours ago
£640
Return
found 16 hours ago
Select Alaska Airlines flight, departing Wed, 20 May from St. Louis to Washington, returning Wed, 27 May, priced at £640 found 16 hours ago
Alaska Airlines
Mon, 18 May - Mon, 25 May
STL
St. Louis
IAD
Washington
£653 Return, found 16 hours ago
£653
Return
found 16 hours ago
Select Alaska Airlines flight, departing Mon, 18 May from St. Louis to Washington, returning Mon, 25 May, priced at £653 found 16 hours ago
Alaska Airlines
Wed, 20 May - Wed, 27 May
STL
St. Louis
IAD
Washington
£672 Return, found 16 hours ago
£672
Return
found 16 hours ago
Select Alaska Airlines flight, departing Wed, 20 May from St. Louis to Washington, returning Wed, 27 May, priced at £672 found 16 hours ago
Alaska Airlines
Fri, 15 May - Fri, 22 May
STL
St. Louis
IAD
Washington
£682 Return, found 16 hours ago
£682
Return
found 16 hours ago
Select Alaska Airlines flight, departing Fri, 15 May from St. Louis to Washington, returning Fri, 22 May, priced at £682 found 16 hours ago

Frequently asked questions

How much is a flight from STL to Washington Dulles Intl. Airport (IAD)?
If you're planning on travelling between STL and Washington Dulles Intl. Airport (IAD), round-trip journeys start from £553. This price is based on fares available within the last 7 days on Expedia for flights departing within the next year, so don't hang around. Book now and save yourself both money and time. 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-St. Louis Intl. Airport (STL) to IAD?
This differs between air carriers, as each has its own set of terms and conditions. Head to the Customer Service Portal, where you'll find instructions on how to cancel online.
How do I find cheap flights from Lambert-St. Louis Intl. Airport (STL) to IAD that have flexible change policies?
Many airlines offer the option to reschedule your flight without a change fee. All you pay is the difference between the original flight and the new flight. When you're searching for Lambert Field to IAD flights, you'll see a "no change fees" filter for you to select.
How far is the flight from Lambert-St. Louis Intl. Airport (STL) to Dulles Intl. Airport?
With a flight distance of 1,100 kilometres, it's only a hop from Lambert Field to IAD. It might be a quick journey, but it's still worth bringing a good book to read.
Which airlines fly direct from Lambert Field to Washington Dulles Intl. Airport (IAD)?
Operating 60 flights monthly, United Airlines (UA) is a great choice when flying directly from Lambert Field to IAD.
Are STL to Dulles Intl. Airport flight tickets cheaper when they're purchased at the last minute?
Booking your trip from Lambert Field to IAD at the last minute could be your ticket to a fantastic deal. However, it could end up costing you a whole lot more! If you'd rather avoid the risk, book well ahead of your departure date. In fact, Expedia has some of the biggest bargains up to 12 months in advance. If your preferred carrier hasn't released tickets yet, check back often as deals are updated all the time on Expedia.

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?
One-way flights typically cost between £370 and £606 and return flights often range between £272 and £911. 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 Anaa (AAA) to Toronto, ON (YYZ-Pearson Intl.) ticket fares go up or down.
Which airlines fly direct from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
Enter STL to IAD and your travel dates, then apply the 'Nonstop' filter to see only direct flights.
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 traveller to traveller. If you like to fly early, UA offers early morning flights. If price is the most important factor, UA typically offers the lowest fares. UA offers the most daily flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.), which is brilliant 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.)?
When flying 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. For even more choice, look at flights that include layovers, as there are around 49 connecting flights daily. 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 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 at approximately 5:00 AM local time, operated by American Airlines. This is a seasonal service active in November and December. An early departure like this can help maximise 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 typically find the most flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.) on a Friday, with around 33 flights available. This gives you plenty of options for your travel plans. Major airlines on this route include United Airlines, Delta Air Lines, and American Airlines. Friday offers notably more flight options compared to other days of the week.
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 morning, from 6am to 9am. About 37% of passengers prefer this time. Many major carriers, including United Airlines and Delta Air Lines, offer flights during this window. This timing works well because it allows you to get an early start on your travel day and arrive at your destination with plenty of time.
How long does it take to fly from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
Direct flights from STL to IAD usually take about 2 hours 20 minutes, traveling roughly 695 miles. If you opt for a connecting flight, expect to add around 2 hours 30 minutes to your journey. Keep in mind that actual flight times can vary due to wind patterns, weather, and air traffic.
Can you fly business or first class from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Washington, DC (IAD-Washington Dulles Intl.)?
Select the "Business class" and "First class" filters when looking for STL to IAD flights on Expedia. This is the easiest way to compare prices, routes and flight times for your trip.
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 from Lambert-St. Louis Intl. (STL)?
From Lambert-St. Louis Intl. (STL), you can fly into Ronald Reagan Washington National (DCA) and Washington Dulles Intl. (IAD) in Washington. Some flights may connect through major hubs like Love Field (DAL), Clinton National Airport (LIT), Nashville Intl. (BNA) 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
Return price
£553
Distance
1111 km
Average flight time
3 hours 13 mins

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