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

View AU$256 flight on Wed, 17 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 for one-way flights and round trip tickets for the period specified. Prices and availability are subject to change. Additional terms apply.

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

February is typically the cheapest month to fly

From AU$231 - AU$933 per traveller.

Graph displaying average flight prices per month

Flight from St. Louis to Washington route information
Origin airport
Lambert-St. Louis Intl.
Destination airport
Washington Dulles Intl.
Distance
1111 km
Average flight time
3 hours 8 mins

Your quick guide to flights from St. Louis to Washington

Pick up great flights from St. Louis to Washington

With Expedia, you have your pick of 7 flights a day with 20 airlines covering flights from St. Louis to Washington. Whether you’re on a business trip, a family holiday or a luxury break, just enter your travel dates, hit search then check out your choice of flights. Select from return, one way or multi-city flights, and use the advance search tool if you want a direct or refundable flight. You can narrow your search to show you just your preferred cabin class and airline, too. It’s all easy. You can book direct flights from St. Louis to Washington that take around 2 hours.

Find cheap flights from St. Louis to Washington

From the great flight deals with prices currently ranging from to , you can choose to see the cheapest flights first. Generally, you can book the cheapest flights from St. Louis to Washington around 4 to 6 weeks in advance. If your travel dates are flexible, try to avoid weekends and peak seasons – when you are more likely to grab the lowest prices. Even last minute, there are some impressive deals. The cheapest time to fly to Washington is normally in .

Reasons to book your flight from St. Louis to Washington with Expedia

Expedia makes it easy to find, book, and travel, with everything you need all in one place. When you enter your travel details, find fantastic deals just for you on flight tickets from St. Louis to Washington across all the main airline carriers, so you can save time, dollars, and hassle finding the perfect flight. If you think your plans could change, choose refundable flights so any changes won’t cost you more. Book your flight to Washington right now and, if you join Expedia Rewards, you earn points this time and every time you travel with Expedia.

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 . 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.

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Washington Flight Deals

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