STL - IAD

$99 Find Cheap Flights from St. Louis to Washington Dulles Airport

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from St. Louis to Dulles Intl departing on 8/9. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy

KAYAK searches hundreds of travel sites at once for deals on flights to Washington, D.C. Dulles Intl Airport

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from St. Louis to Washington, D.C., as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from St. Louis to Washington, D.C., as well as popular online travel agencies
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Flights Deals

Cheap Flights from St. Louis to Dulles Intl (STL-IAD)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from St. Louis to Dulles Intl that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from St. Louis to Dulles Intl

Sat, Aug 16 - Sat, Aug 23
Frontier Logo
2:52 pm - 11:26 pmSTL-IAD
7h 34m1 stop
Frontier Logo
6:10 am - 1:33 pmIAD-STL
8h 23m1 stop
$198Frontier
Find Deal
Sat, Aug 30 - Mon, Sep 1
Frontier Logo
3:02 pm - 11:00 pmSTL-IAD
6h 58m1 stop
Frontier Logo
6:10 am - 12:56 pmIAD-STL
7h 46m1 stop
$208Frontier
Find Deal
Sat, Aug 16 - Sun, Aug 24
Frontier Logo
2:52 pm - 11:26 pmSTL-IAD
7h 34m1 stop
Frontier Logo
9:33 pm - 2:21 pmIAD-STL
17h 48m1 stop
$215Frontier
Find Deal
Sat, Oct 11 - Tue, Oct 14
Delta Logo
5:20 pm - 11:18 pmSTL-IAD
4h 58m1 stop
Delta Logo
7:00 am - 10:26 amIAD-STL
4h 26m1 stop
$237Delta
Find Deal
Wed, Aug 20 - Wed, Aug 27
United Airlines Logo
8:15 am - 11:25 amSTL-IAD
2h 10mnonstop
United Airlines Logo
8:40 am - 10:02 amIAD-STL
2h 22mnonstop
$245United Airlines
Find Deal
Wed, Aug 20 - Sat, Aug 23
United Airlines Logo
6:35 am - 1:49 pmSTL-IAD
6h 14m1 stop
United Airlines Logo
8:40 am - 10:02 amIAD-STL
2h 22mnonstop
$254United Airlines
Find Deal
Sat, Aug 30 - Mon, Sep 1
American Airlines Logo
1:01 pm - 7:42 pmSTL-IAD
5h 41m1 stop
American Airlines Logo
6:34 am - 12:02 pmIAD-STL
6h 28m1 stop
$271American Airlines
Find Deal
Wed, Nov 5 - Sat, Nov 8
American Airlines Logo
6:04 pm - 11:07 pmSTL-IAD
4h 03m1 stop
American Airlines Logo
8:09 pm - 12:05 amIAD-STL
4h 56m1 stop
$273American Airlines
Find Deal
Thu, Oct 9 - Wed, Oct 15
Delta Logo
6:52 pm - 12:12 amSTL-IAD
4h 20m1 stop
Delta Logo
12:27 pm - 3:55 pmIAD-STL
4h 28m1 stop
$287Delta
Find Deal
Sun, Aug 17 - Thu, Aug 21
 Logo
10:37 am - 2:23 pmSTL-IAD
26h 46m3 stops
 Logo
4:56 pm - 1:32 pmIAD-STL
21h 36m3 stops
Expert advice

Expert advice for your flight from St. Louis to Dulles Intl

 
Snippets provided in this section are AI-generated based on a summarization of KAYAK-commissioned articles. The articles are presented as-is, for general informational purposes only, and may not be up-to-date. The opinions contained in the articles are original to the author and reflect their authentic experience, which may vary significantly from the experience of others.
KAYAK teamed up with top travel experts to share the best tips for your journey.
Airlines
Lufthansa

Lufthansa's Economy Flex allows free rebooking, ideal for flexible travel plans.


Lufthansa offers FlyNet Messaging for free to Miles & More members on short-haul flights.

Read more about Lufthansaby Jessica Macdonald
United Airlines

United offers Priority Boarding to avoid gate-checking carry-ons, ideal for quick boarding.


United's Economy Plus seats offer up to six inches more legroom than standard economy.

Airports
STL

Avoid peak hours at STL to minimize wait times. Early mornings and afternoons can be particularly crowded.

Read more about STLby Yulia Denisyuk
IAD

Use the Silver Line Metro for a convenient 50-minute ride from IAD to downtown D.C. It's cost-effective and avoids traffic.

Read more about IADby Stefanie Waldek
Our travel experts
Jessica Macdonald

Jessica Macdonald

Expert on Lufthansa

Jessica Macdonald

Jessica Macdonald

Currently based in Scotland after living in South Africa and the United States, Jessica has been writing travel and aviation content for more than 10 years. She regularly contributes to Travel + Leisure and TripSavvy, and has had work published by Condé Nast Traveller and The Independent. She has traveled to more than 50 countries across six continents.

Read more
Stefanie Waldek

Stefanie Waldek

Expert on United Airlines and IAD

Stefanie Waldek

Stefanie Waldek

Stefanie Waldek is a freelance space, travel, and design writer based in Saratoga Springs, NY. Her words have appeared in Space.com, Travel + Leisure, Condé Nast Traveler, Architectural Digest, and House Beautiful, among other publications. An expert in aviation and expedition cruising, Stefanie is frequently up in the air or on the sea, likely en route to Antarctica or the Arctic.

Read more
Yulia Denisyuk

Yulia Denisyuk

Expert on STL

Yulia Denisyuk

Yulia Denisyuk

Yulia is a freelance journalist who’s dispatched from 90+ countries. Her work focuses on cultures, adventure trips and air travel, appearing in NatGeo, NYT, CNTraveler, and more. For past assignments, she’s stayed with nomads in Mongolia and learned the art of Imigongo in Rwanda. She’s based in Chicago; in winter she often questions that decision.

Read more
Booking Insights

KAYAK's insights & trends for St. Louis to Dulles Intl flights

Get data-powered insights and trends into flights from St. Louis to Dulles Intl to help you find the cheapest flights, the best time to fly and much more.

How much is a round-trip flight from St. Louis to Washington, D.C. Dulles Intl Airport?

What’s the cheapest day of the week to fly from St. Louis to Washington Dulles Airport?

The average price of all round-trip flights from St. Louis to Washington, D.C. Dulles Intl Airport clicked on KAYAK for each day over the last 12 months.

When flying from St. Louis to Washington Dulles Airport, you should consider leaving on a Friday and avoid Mondays if you are looking for the best rates. For your return to St. Louis, you’ll find the best rates on Wednesdays and the most expensive ones on Fridays.

What is the cheapest month to fly from St. Louis to Washington, D.C. Dulles Intl Airport?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from St. Louis to Washington, D.C. Dulles Intl Airport, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from St. Louis to Washington, D.C. Dulles Intl Airport is August, where tickets cost $294 (return) on average. On the other hand, the most expensive months are July and October, where the average cost of round-trip tickets is $611 and $478 respectively.

Can I save money by flying with a layover from St. Louis to Washington, D.C. Dulles Intl Airport?

The average round-trip price for all non-stop flights, flights with one layover, and flights with two layovers for the route found by users searching on KAYAK in the last 2 weeks.

Yes, flying with a layover may cost you more time, but you can also save money on the route, with a 1 stop layover the cheapest option at $557 on average.

How far in advance should I book a flight from St. Louis to Washington, D.C. Dulles Intl Airport?

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from St. Louis to Washington, D.C. Dulles Intl Airport, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from St. Louis to Washington, D.C. Dulles Intl Airport, you should book around 4 weeks before departure, which saves you about 31% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 14 weeks before departure.

Good to know

Low seasonMarch
Cheapest flight$99
Best time to beat the crowds with an average 21% drop in price.
Most popular time to fly with an average 61% increase in price.
Flight from St. Louis to Washington Dulles Airport

When to book flights from St. Louis to Dulles Intl

Are your dates flexible? Find out the best times to travel from St. Louis to Dulles Intl based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking St. Louis to Washington Dulles Airport flights

  • What is the cheapest flight from St. Louis to Washington, D.C. Dulles Intl Airport?

    In the last 3 days, the lowest price for a flight from St. Louis to Washington, D.C. Dulles Intl Airport was $99 for a one-way ticket and $198 for a round-trip.

  • Do I need a passport to fly between St. Louis and Washington Dulles Airport?

    No

  • Which airports will I be using when flying from St. Louis to Washington Dulles Airport?

    When flying out of St. Louis you will be using Lambert-St Louis. You will be landing at Washington Dulles Airport, also known as Washington, D.C. Dulles Intl.

  • Which airlines offer Wi-Fi service onboard planes from St. Louis to Washington Dulles Airport?

    Lufthansa, American Airlines, Delta, and United Airlines offer inflight Wi-Fi service on the St. Louis to Washington Dulles Airport flight route.

  • Which aircraft models fly most regularly from St. Louis to Washington Dulles Airport?

    The Canadair (Bombardier) Regional Jet CRJ-550 is the aircraft model that flies most regularly on the St. Louis to Washington Dulles Airport flight route.

  • Which airline alliances offer flights from St. Louis to Washington Dulles Airport?

    Star Alliance is the only airline alliance operating flights between St. Louis and Washington Dulles Airport.

  • On which days can I fly direct from St. Louis to Washington Dulles Airport?

    There are nonstop flights from St. Louis to Washington Dulles Airport on a daily basis.

  • Which is the best airline for flights from St. Louis to Washington, D.C., Delta or United Airlines?

    The two airlines most popular with KAYAK users for flights from St. Louis to Washington, D.C. are Delta and United Airlines. With an average price for the route of $261 and an overall rating of 8.0, Delta is the most popular choice. United Airlines is also a great choice for the route, with an average price of $437 and an overall rating of 7.4.

  • How does KAYAK find such low prices on flights from St. Louis to Washington Dulles Airport?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from St. Louis to Washington Dulles Airport.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from St. Louis to Washington Dulles Airport?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Washington Dulles Airport from St. Louis is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from St. Louis to Washington Dulles Airport?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Washington Dulles Airport with an airline and back to St. Louis with another airline. Booking your flights between St. Louis and IAD can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from St. Louis to Washington Dulles Airport?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Washington Dulles Airport from St. Louis up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

KAYAK’s top tips for finding a cheap flight from St. Louis to Washington, D.C. Dulles Intl Airport

  • Looking for a cheap flight? 25% of our users found flights on this route for $267 or less one-way and $787 or less round-trip.

Prefer to fly direct from St. Louis to Washington Dulles Airport?

 
Direct data is based off flight results for the next 60 days. Find direct flights from all airlines flying direct from Lambert-St Louis to Washington, D.C. Dulles Intl.
Find which airlines fly direct from Lambert-St Louis Airport to Washington, D.C. Dulles Intl Airport, which days they fly and book direct flights.

Direct departures

Lambert-St Louis to Washington, D.C. Dulles Intl

Monday

Avianca, Brussels Airlines, Copa Airlines, +2 more

Avianca, Brussels Airlines, +3 more

Tuesday

Avianca, Brussels Airlines, Copa Airlines, +2 more

Avianca, Brussels Airlines, +3 more

Wednesday

Avianca, Brussels Airlines, Copa Airlines, +2 more

Avianca, Brussels Airlines, +3 more

Thursday

Avianca, Brussels Airlines, Copa Airlines, +2 more

Avianca, Brussels Airlines, +3 more

Friday

Avianca, Brussels Airlines, Copa Airlines, +2 more

Avianca, Brussels Airlines, +3 more

Saturday

Avianca, Brussels Airlines, Copa Airlines, +2 more

Avianca, Brussels Airlines, +3 more

Sunday

Avianca, Brussels Airlines, Copa Airlines, +2 more

Avianca, Brussels Airlines, +3 more

See more direct flights

Direct returns

Washington, D.C. Dulles Intl to Lambert-St Louis

Monday

Avianca, Brussels Airlines, Copa Airlines, +2 more

Avianca, Brussels Airlines, +3 more

Tuesday

Avianca, Brussels Airlines, Copa Airlines, +2 more

Avianca, Brussels Airlines, +3 more

Wednesday

Avianca, Brussels Airlines, Copa Airlines, +2 more

Avianca, Brussels Airlines, +3 more

Thursday

Avianca, Brussels Airlines, Copa Airlines, +2 more

Avianca, Brussels Airlines, +3 more

Friday

Avianca, Brussels Airlines, Copa Airlines, +2 more

Avianca, Brussels Airlines, +3 more

Saturday

Avianca, Brussels Airlines, Copa Airlines, +2 more

Avianca, Brussels Airlines, +3 more

Sunday

Avianca, Brussels Airlines, Copa Airlines, +2 more

Avianca, Brussels Airlines, +3 more

See more direct flights

Reviews of the top 3 airlines serving from St. Louis to Dulles Intl

 
See real verified KAYAK customer reviews for airlines flying from St. Louis to Washington, D.C.. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from St. Louis to Dulles Intl? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.0
DeltaOverall score based on 7980 reviews
7.3Food
8.2Boarding
7.9Comfort
8.5Crew
7.9Entertainment
Airline reviews

Delayed and took off even later than the scheduled delay time

8.0 ExcellentAnonymous, Jul 2025DTW - SEA
Read more Delta reviews

Delayed and took off even later than the scheduled delay time

For a 69 year old with health problems I had the worse experience, no wheelchair when I entered a lady told me to sit and wait while a gentleman told me I had to walk to the Delta station, which I did. I had a carry on and a bag, and I was traveling with my service dog, which was on his carrier and the lady charged me for my carry on luggage, beside all the waiting cause of the delay, I had to walk to get my luggage cause no wheelchair showed up, I am so disappointed. I will get in touch with the company. I got home at 3:00 am, not good for my health situation.

Great experience on Delta. Staff from baggage check to flight attendants were very courteous and professional. My only issue was a personal preference for pretzels instead of the chips and cookies that were offered.

There was no problems, just a little uncomfortable with seats that do not lay back a little

Always good but we must do something about people in rows ahead of you that don't put their seats back up when they are suppose to. And It's rough to not be able to even lean over to get something out of my purse.

Flight was delayed, 30+ bags had to be gate checked. Crew were very friendly!

Everything was good until we were boarding our connection flight in Atlanta, we were told to gate check our carry-on, but when we got inside the plane, there was plenty of room in the overhead.

Did not know my son and I had different seating arrangements. He was fine, but it was disappointing.

Flight was canceled, and no effort was made to help with rebooking, no hotel vouchers, no car transportation and minimal food voucher and most places for food were closed by the time the voucher was given. Waited for 3 hours for bags. Simply the worst travel experience I have ever had

Food was surprisingly good but the WiFi was not great

Had one staff that was not pleasant. Seems they are stressed with too many people to care for.

I would have liked an opportunity to move to a different seat ( even would have checked in my hand luggage)as I had health issues where I didn't have to clamber over the passenger next to me to for toilet use/ movement [ She was a highly unpleasant neighbor to sit next to]. In addition, I found that my European phone plan had run out of data and so I was not receiving emails from yourselves on airport wifi to be able to check in online and verifications difficult as did not accept the ticket number I had. I asked for an extra blanket but was told there was none. Then I saw other passengers receiving them. I couldn't eat the food and asked for snacks : Stewardess said " on the way" but they did not bring. The best bit was the check in process in Lisbon. Very efficient. However, I did not understand why we had to collect our bags at Washington then go through customs again. It was not explained. I also with my leg and health issue had approximately mile walk to the gate ( which then changed) . There appeared to be no moving walkways or help provided.

The attendant were friendly. I suggest you have a medical attendant on board every flight so that in case someone is sick , he/she will help them.

We had a very long diversion and our food voucher didn’t work because the restaurants were closed

United airlines, mediocre at best. No issues , nothing great . Worked for me

Turbulent taking off & landing to Dulles from Raleigh. Flight from Dulles to Tokyo very good!!

Very nice and clean plane. Transit time between flights was tight though

Mostly the experience was good except for the flight changes made by UA which meant longer layover in DC

Terrible. First of all we were delayed 4 3/4 hours departing Honolulu. As we had to leave our condo and the rental car had to be returned we had to go to the airport. Even though we had a business class boarding pass to Washington, since we did not have business class to Montreal we could not access the lounge without paying a $59 fee each. This does not make sense to us. Since we could not meet our original connection United booked us to Montreal via New York LaGuardia on Air Canada. In Washington a further delay got us into LaGuardia too late to make our connection to Montreal so we were booked on another Air Canada flight 3 hours later. We were originally scheduled to arrive in Montreal at 10:40 and arrived at 19:55. A totally exhausting day, United did not offer a meal voucher or any type of compensation. Air Canada did give us a digital meal voucher. The food in United business class is poor among all meals offered. The pods look nice but are not that confortable. Overall would not fly on United again.

Change cabin crew assisting business class. Not taking care, ignoring requests and calls. Never had such an experience in business class.

After we'd boarded , they canceled the flight. The crew didn't even know , we just all received text messages. Then after they deplaned us , AA was just like "too bad, go F your self, we sure ain't gonna help you"

Initial flight was cancelled at the time of arrival to the airport, flight alternative requires switching from direct to flight with a layover, and the plane felt like it would split apart, it was so rattle-y.

Weather delay for 2.5 hours followed by half hour crew delay, did not have ginger ale, uncomfortable seats

It was nobody’s fault - but the plane came 4-hrs late and we were updated randomly in 20-30 mins increments which left us hostage to sit and wait expectantly. It was very long and got very late. Our plane didn’t land until nearly 1 am! Also the toilet wasn’t working. The hosts were nice enough but were clearly “about to pass out” as one told me. Lastly, there was no snack or even time for it. Just a bad experience overall.

The boarding crew was incredibly helpful getting me on an earlier flight

Two flight changes before the scheduled flight. On the day of the flight, the flight was delayed, which caused the connecting flight to be missed. Then, I was directed to another airport (CUN) and traveled to Tulum. American gave a $12 voucher for lunch. The least expensive item on the menu at a Mexican restaurant was $9.99. Driving to Tulum was a bad auto crash, and traffic was delayed two-plus hours. The bottom line is that we should have been at the hotel at noon, but it ended up at 11:30 PM.

Great experience. Flight boarded easily. Departed early. Smooth flight. Great arrival in DC--almost no taxing! Almost direct to gate from runway. Crew was terrific. Same cookies and beverages in main cabin. I did not use the entertainment system on this flight.

Flight delayed on both ends - have a gate ready at DCA, don't make us sit for 30min after being late to take off as well.

AA can't control the weather. But the airplane was hot and stuffy while stuck on the runway with a broken entertainment system.

Miami lounges were overcrowded and we were unable to get in. We only had a short time. But the banks are too tight in all American hubs

Everything you need to know for your flight from St. Louis to Dulles Intl

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