STL - IAD

$90 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 7/1. 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.
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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 Flight Deals 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.

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

KAYAK's recommended round-trip deals from the most popular airlines that fly from St. Louis to Dulles Intl.
Discover the best prices for you by selecting your travel dates on KAYAK.
Frontier Logo
2:25 pm - 5:55 amSTL-IAD
14h 30m1 stop
Frontier Logo
1:34 pm - 11:49 pmIAD-STL
11h 15m1 stop
$198Frontier
Find Deal
Thu, May 29 - Mon, Jun 2
Delta Logo
5:40 pm - 12:28 amSTL-IAD
5h 48m1 stop
Delta Logo
6:00 am - 11:54 amIAD-STL
6h 54m1 stop
$199Delta
Find Deal
Thu, May 29 - Sat, May 31
United Airlines Logo
5:00 am - 11:55 amSTL-IAD
5h 55m1 stop
United Airlines Logo
8:40 am - 9:56 amIAD-STL
2h 16mnonstop
$204United Airlines
Find Deal
Thu, May 29 - Sat, May 31
United Airlines Logo
8:15 am - 11:23 amSTL-IAD
2h 08mnonstop
United Airlines Logo
3:40 pm - 9:25 pmIAD-STL
6h 45m1 stop
$210United Airlines
Find Deal
Wed, May 28 - Wed, Jun 4
United Airlines Logo
8:15 am - 11:23 amSTL-IAD
2h 08mnonstop
United Airlines Logo
8:40 am - 9:56 amIAD-STL
2h 16mnonstop
$212United Airlines
Find Deal
Thu, May 29 - Sat, May 31
United Airlines Logo
5:33 pm - 12:30 amSTL-IAD
5h 57m1 stop
United Airlines Logo
8:40 am - 9:56 amIAD-STL
2h 16mnonstop
$214United Airlines
Find Deal
Sat, May 24 - Mon, May 26
American Airlines Logo
6:47 pm - 12:02 amSTL-IAD
4h 15m1 stop
American Airlines Logo
8:14 pm - 11:59 pmIAD-STL
4h 45m1 stop
$251American Airlines
Find Deal
Sat, May 31 - Tue, Jun 10
American Airlines Logo
5:30 am - 10:48 amSTL-IAD
4h 18m1 stop
American Airlines Logo
8:14 pm - 11:59 pmIAD-STL
4h 45m1 stop
$317American Airlines
Find Deal
Sat, Jun 28 - Sun, Jun 29
 Logo
6:12 pm - 8:37 pmSTL-IAD
25h 25m2 stops
 Logo
9:42 pm - 6:41 pmIAD-STL
21h 59m2 stops
Thu, Jun 19 - Sat, Jun 21
 Logo
10:10 am - 11:20 amSTL-IAD
24h 10m3 stops
 Logo
11:54 am - 6:41 pmIAD-STL
7h 47m2 stops
Sun, May 25 - Sun, Jun 1
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 are busiest, so plan flights during off-peak times for a smoother experience.

Read more about STLby Yulia Denisyuk
IAD

Use the Silver Line Metro for a convenient trip from IAD to downtown D.C. It takes about 50 minutes and is cost-effective compared to taxis.

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
Useful Info

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.

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 Saturdays 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 January, where tickets cost $299 (return) on average. On the other hand, the most expensive months are July and October, where the average cost of round-trip tickets is $523 and $464 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.

No, with an average price for the route of $1,011, prices are generally cheapest when you fly direct.

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. For the absolute cheapest price, our data suggests you should book 23 weeks before departure.

Good to know

Low seasonMarch
High seasonMay
Cheapest flight$90
Best time to beat the crowds with an average 22% drop in price.
Most popular time to fly with an average 16% 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 $90 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?

    American Airlines, Delta, Alaska Airlines, United Airlines, and Lufthansa 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 $266 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 $442 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 $204 or less one-way and $862 or less round-trip.

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

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
See more direct flights

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 7936 reviews
8.2Boarding
7.3Food
7.9Comfort
7.9Entertainment
8.5Crew
Airline reviews

Delta is my preferred airline. I've traveled with them for years. On time in most cases, good communication, easy to use app. Most planes are pretty nice. I was on a CRJ 700/900 however, which was pretty badly aged inside and needed a refresh. No infotainment, unreliable wifi, best to download before boarding or bring a book. Food choices are really just snacks on this flight, nice variety but about what you'd expect. Great staff and prompt in departure and early arrival too. Overall quite satisfied.

8.0 ExcellentFredrick, Apr 2025GSO - DTW
Read more Delta reviews

Delta is my preferred airline. I've traveled with them for years. On time in most cases, good communication, easy to use app. Most planes are pretty nice. I was on a CRJ 700/900 however, which was pretty badly aged inside and needed a refresh. No infotainment, unreliable wifi, best to download before boarding or bring a book. Food choices are really just snacks on this flight, nice variety but about what you'd expect. Great staff and prompt in departure and early arrival too. Overall quite satisfied.

Crew was friendly Love the entertainment in the seat head rest.

Delta flight was on time, seats were comfortable, and crew was nice.

This had nothing to do with Delta… The flights were on time and flawless. The service was excellent. We purchased seats in (aisle/middle) comfort plus since this was a cross country flight. Unfortunately, the woman seated at the window was 300+ pounds and, as might be expected, covered up about a third of the middle seat also. there was absolutely nothing that Delta could have done about that… I just don’t know what the answer should be. If you purchase a seat, you should should be able to use the entire seat and not just the portion that someone else is not sitting/oozing in. Disappointing…there should be something that could be done….I'm just not sure what solution could be.

Delayed take-off. Very small plane so very scary with lots of bumps during the flight. Would never fly Delta on short flights in small 80 seaters plane again! Felt relieved when landed.

The worst part was I was NOT allowed in the lounge even though I was holding a first class ticket and have a premium American Express card. I have flown Business or First Class with many airlines. Delta is the ONLY one who does not extend this courtesy to anyone except people who hold the very expensive American Express card. As a result, I won’t fly Delta if I have any other choice.

A little bumpy ride . No food was being provided due the the turbulence. That was ok it was a short flight to my standards.

Simply outstanding. Their new lounge for Delta One customers is a cut above the rest.

The Dekta Rep that checked us in was great. She's very personable, pleasant, and can tell she enjoys her job.

The plane was old with small storage areas that had problems closing/latching and not enough storage for everyone, and worn, damaged seats. Service was great but feel a little unsafe on such well used planes.

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.

United left one of our bags back in SFO but that’s not my real complaint. The complaint is how it all went down. So we checked in the day before online and were told we could use the quick drop for luggage. So the next day I used baggage quick drop curbside at SFO. The agent mistakenly didn't tag my bag as he put my bag on the conveyor belt untagged. We immediately alerted him he had not tagged the bag. I walked with him to the baggage service office to find my bag and tag it. We waited outside the office for 10 mins. He came out and said everything was ok and the bag was going to be tagged and on my flight. We received a text that one of our bags was on the flight but the other was not. I alerted my first class flight attendant immediately upon boarding the flight. She was helpful and said she’d get it sorted out right away. She called over the gate agent. The gate agent used my bag number and looked over information on her device. She said my bag was on the flight. The flight attendant was standing with her, looking at the device, and also said “yep it’s on the flight”. During the flight the flight attendant made reference to how reassuring it must feel knowing the bag was on the flight. Upon arriving to IAD we received a text that my bag was not on my flight. The text said my bag would arrive to my final destination LIS 24 hrs late. I understand that mistakes happen. I was totally ok with my bag mistakenly not getting tagged at the quick drop. I was fine with walking down to baggage services to tag my bag. But, what I am not ok with is that the United staff said they fixed the mistake two different times, assuring me twice that my bag would be/was on the plane…and it wasn’t. I expected better attention by the employees, for them to do what they said they were going to do. We also spent extra money to upgrade our seats to first class, including the entire return leg from Lisbon to San Francisco because we wanted a smoother and more relaxing travel experience. Our money was not well spent. We will not be using United for travel going forward.

The flight was delayed, it took longer than anticipated because of weather, and they broke my luggage.

Horrifying! And I am almost 2 million miles with United. Late by 3 1/2 hours. Worst: after two hours on the plane waiting, they decided that one of the tires had been damaged and then decided to change it. Another hour and a half to change the tire!!!!! NO EXCUSE FOR THIS. The crew didn't even offer a glass of water until we had been on the plane for FIVE hours. This is the worst airline in the world. I'm simply stuck because they fly on the only routes I need.

Gate got changed about 4 times. Very confusing and very crowded. If you don’t have wifi to help get updates, you can be in deep trouble.

Attendants zipped through cabin so fast hardly anyone got the water they told us we could have in the short flight. Nothing else was offered.

Sucks ! All three flights I was on this trip were delayed.

The flight attendants were unhelpful. It was a packed flight, and usually a flight attendant would help find a spot in the bin for your carry on or shift things around. Neither made any effort to do so. Also, I had to then check my bag. I was told it would be on the carousel in YYZ, but it came up on the jetway. So lucky I saw others standing around for their bags. I would have walked straight past this and on to the carousel. They could have at least told me that they had given me wrong information. Very unsatisfactory.

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

very bare bones flight no entertainment screen, download shows prior to boarding to watch on phone or tablet.

It was good. It’s been a long time since my wife and I fly any where and things have changed. Our trip was to see our new grandson. We fly economy and that was not good for my bad back. It was a quick flight but uncomfortable.

Service in first class no longer exists on American Airlines .

Flight was delayed by 11 hours. Flight agent finally had to rebook us, but did not rebook fully correctly. We had to pay out of pocket to get to the hotel they booked us and couldn’t check in the next day online because the next day’s agent said they didn’t complete the process the night before.

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

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