IAD - STL

$90 Find Cheap Flights from Washington Dulles Airport to St. Louis

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Dulles Intl to St. Louis departing on 5/25. 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

KAYAK searches hundreds of travel sites at once for deals on flights to St. Louis

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Washington, D.C. to St. Louis, 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 Washington, D.C. to St. Louis, as well as popular online travel agencies
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Cheap Flight Deals from Dulles Intl to St. Louis (IAD-STL)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Dulles Intl to St. Louis 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 Dulles Intl to St. Louis

KAYAK's recommended round-trip deals from the most popular airlines that fly from Dulles Intl to St. Louis.
Discover the best prices for you by selecting your travel dates on KAYAK.
Choose your dates
Frontier Logo
5:26 pm - 12:14 amIAD-STL
7h 48m1 stop
Frontier Logo
5:45 pm - 4:36 pmSTL-IAD
21h 51m1 stop
$200Frontier
Find Deal
Fri, May 9 - Sat, May 10
Delta Logo
6:00 am - 9:00 amIAD-STL
4h 00m1 stop
Delta Logo
3:40 pm - 9:08 pmSTL-IAD
4h 28m1 stop
$224Delta
Find Deal
Thu, May 22 - Sat, May 24
Frontier Logo
5:26 pm - 12:06 amIAD-STL
7h 40m1 stop
Frontier Logo
9:55 pm - 6:31 amSTL-IAD
31h 36m1 stop
$230Frontier
Find Deal
Thu, May 1 - Fri, May 2
United Airlines Logo
6:22 am - 12:19 pmIAD-STL
6h 57m1 stop
United Airlines Logo
8:25 am - 11:34 amSTL-IAD
2h 09mnonstop
$239United Airlines
Find Deal
Fri, May 9 - Sat, May 10
United Airlines Logo
6:48 am - 12:20 pmIAD-STL
6h 32m1 stop
United Airlines Logo
5:27 pm - 12:30 amSTL-IAD
6h 03m1 stop
$246United Airlines
Find Deal
Thu, May 29 - Sat, May 31
Sun Country Air Logo
12:49 pm - 11:25 amIAD-STL
23h 36m1 stop
Sun Country Air Logo
10:20 am - 11:53 amSTL-IAD
24h 33m1 stop
$275Sun Country Air
Find Deal
Thu, May 22 - Sun, May 25
American Airlines Logo
5:02 am - 8:56 amIAD-STL
4h 54m1 stop
American Airlines Logo
6:47 pm - 12:02 amSTL-IAD
4h 15m1 stop
$282American Airlines
Find Deal
Fri, May 9 - Tue, May 13
American Airlines Logo
11:07 am - 2:07 pmIAD-STL
4h 00m1 stop
American Airlines Logo
9:09 am - 5:09 pmSTL-IAD
7h 00m1 stop
$297American Airlines
Find Deal
Sat, Jul 26 - Tue, Jul 29
 Logo
12:45 pm - 11:31 amIAD-STL
23h 46m1 stop
 Logo
10:10 am - 8:57 pmSTL-IAD
33h 47m2 stops
Thu, May 1 - Thu, May 8
 Logo
11:58 am - 3:22 pmIAD-STL
28h 24m2 stops
 Logo
6:36 am - 9:23 amSTL-IAD
25h 47m2 stops
Thu, Jul 3 - Sun, Jul 6

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

Get data-powered insights and trends into flights from Dulles Intl to St. Louis 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 Washington Dulles Airport to St. Louis?

The average price of all round-trip flights from Washington, D.C. Dulles Intl Airport to St. Louis clicked on KAYAK for each day over the last 12 months.
For Washington Dulles Airport to St. Louis, Wednesday is the cheapest day to fly on average and Friday is the most expensive. Flying from St. Louis back to Washington Dulles Airport, the best deals are generally found on Friday, with Saturday being the most expensive.

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

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Washington, D.C. Dulles Intl Airport to St. Louis, 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 Washington, D.C. Dulles Intl Airport to St. Louis is February, where tickets cost $325 (return) on average. On the other hand, the most expensive months are December and May, where the average cost of round-trip tickets is $499 and $481 respectively.

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

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 $482, prices are generally cheapest when you fly direct.

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

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Washington, D.C. Dulles Intl Airport to St. Louis, 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 Washington, D.C. Dulles Intl Airport to St. Louis, you should book around 3 weeks before departure. For the absolute cheapest price, our data suggests you should book 18 weeks before departure.

Good to know

Low season

February

High season

August

Cheapest flight

$90
Best time to beat the crowds with an average 23% drop in price.
Most popular time to fly and prices are also 6% lower on average.
Flight from Washington Dulles Airport to St. Louis

When to book flights from Dulles Intl to St. Louis

Are your dates flexible? Find out the best times to travel from Dulles Intl to St. Louis 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 Washington Dulles Airport to St. Louis flights

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

    In the last 3 days, the lowest price for a flight from Washington, D.C. Dulles Intl Airport to St. Louis was $90 for a one-way ticket and $200 for a round-trip.

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

    No, a passport isn't needed to fly from Washington Dulles Airport to St. Louis. However, local authorities might ask for an official ID.

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

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

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

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

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

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

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

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

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

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

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

    The two airlines most popular with KAYAK users for flights from Washington, D.C. to St. Louis are Delta and United Airlines. With an average price for the route of $310 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 $490 and an overall rating of 7.4.

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

    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 Washington Dulles Airport to St. Louis.

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to St. Louis from Washington Dulles Airport 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 Washington Dulles Airport to St. Louis?

    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 St. Louis with an airline and back to Washington Dulles Airport with another airline. Booking your flights between Washington Dulles Airport and STL 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 Washington Dulles Airport to St. Louis?

    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 St. Louis from Washington Dulles Airport up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

See more FAQs

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

  • Looking for a cheap flight? 25% of our users found flights on this route for $123 or less one-way and $303 or less round-trip.

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

Find which airlines fly direct from Washington, D.C. Dulles Intl Airport to Lambert-St Louis Airport, which days they fly and book direct flights.

Direct departures

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

Direct returns

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
See more direct flights

Top 3 airlines serving from Dulles Intl to St. Louis

 
See real verified KAYAK customer reviews for airlines flying from Washington, D.C. to St. Louis. 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 Dulles Intl to St. Louis? 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 7897 reviews
8.0Comfort
8.2Boarding
8.5Crew
7.9Entertainment
7.3Food
Airline reviews

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

8.0 ExcellentSally, Apr 2025GRB - DTW
Read more Delta reviews

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.

Terrible and im avoiding them in the future. My initial flight was delayed causing me to rebook my flight and when speaking with the representative to rebook I explained this is the second time my flights were delayed and they did nothing to help me. I wasn't booked to comfort plus or given a voucher or anything. I was almost late for my meeting that I needed to attend on Monday because of the games delta played delaying my flights even more and putting me in the very back of the plane next to an extremely intoxicated passenger

Flights on time. .Ride was as comfortable as can be expected in steerage. Luggage arrived at destination. Attendants were fairly friendly.

Great staff. Wifi is terrible. Signing up for skylines is a painstaking process. Had to call customer service just to get my flight itinerary and confirmation sent to me. Consistent delays. A well staffed company that is run so poorly. Upper management needs to be renewed.

The WiFi didn't seem as fast as it normally is

Thank you for not flipping the plane on the run way. You guys get a 5 star rating for the flight!!!

The crew was wonderful and attentive. The seats near exit row were restrictive. Offer healthy snacks please

The gate was too far away for the connecting flight

Compared with other carriers business class for an overnight was not worth the extra expense.

Generally good. The aisles have gotten narrower which can slow down boarding. Flight crew was great! Healthier complimentary snacks would be appreciated. Due to earthquake in San Francisco we had to circle in air space for a bit but then had a smooth landing. I laud the flight crew for their patience ;)

We were delayed in Toronto on the tarmac for THREE hours with no clear indication as to why except that it was not a safety hazard. Pilot did apologize more than once but even he was unable to explain why exactly we were delayed. I overheard the stewards saying that the captain was very frustrated with the situation as well because he was not able to explain why except it had something to do with water supply or system on the aircraft and now we needed to wait for an engineer to approve the aircraft for flight. It was very frustrating and distressing as a passenger and we should have been given complimentary meals at the very least.

Flight was cramped with every seat taken. The food was fine, nothing crazy to write home about. The plane felt dated and needing some TLC, the button for the window shade didn't work and there were no AC outlets to use. When communicating with staff all except one nice lady never seemed happy to help me almost like I was bothering them when asked for things like a glass of water or a snack. The flight was overall fine. It did what was needed which is get me from point A to point B. But it certainly was not special. I don't expect much in economy but I believe economy on a host of other airlines is more memorable and better experience.

The flight was heavily booked so boarding was a lengthy process. The FA’s were rather abrupt during this process but became more gracious as the flight went on. Breakfast (puffed pastry and chewy sausage) was pretty horrible but there was fruit and yogurt which they didn’t mess up. Overall it was fine.

Liked nothing. As per previous segment it was delay delay delay.

I completely missed my flight because the first leg was longer than planned. I had to sleep overnight in the airport because no accommodation was provided and then sent to Trinidad in the morning with an anticipated 7 hour layover before my flight to Georgetown which was now with Caribbean Airlines. I tried twice with customer service to see if they could put me on an earlier flight which had seats available but was told it wasn’t possible.

Short flight - no food understandable. Flight was delayed for over an hour. Overall, it was good.

First class felt like economy, seats were horrible, food was horrible, staff inattentive

Wonderful as usual except for other guests that were unruly and not kept in check by the Crew.

The flight was initially delayed, then cancelled. American Airlines says the cancellation was weather related, though the actual weather was not bad in both Washington and Providence and between. There were very few cancellations that day. In fact, AA2120 from Washington, DC to Boston flew with a minor delay at about the same time. So, the weather somehow affected only this particular flight AA5230. The next available flight was the following morning. The American Airlines refused to reimburse accommodation (hotel at DCA)

Fine. On time, cabin service was fine, bag arrived. All good. Flying into DCA so did not collide with any helicopters, which is also good. Horrid incident that could have and should have been prevented.

Good experience but the snacks are not gluten free, so I cannot eat them.

Standard. No different than a discount carrier on a short trip.

Everything was great. Boarding, early departure, early arrival, and deplaning were smooth. Smooth flight.

I blame kayak for my last trip to dca. Kayak cancelled my direct flight and put on a one stop flight and made lost whole day from my vacation and had not even refunded my ticket.

I flew out of Reagan National. My flight was delayed, delayed, delayed, and then canceled ...THREE TIMES over TWO DAYS. Staff were seemingly not empowered to provide information on why the flights were screwed up. A real nightmare.

I had two wonderful flights - very relaxing and got me there early!

Cancelled and rebooked twice in one day with a drop in seat class. Not good at all.

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

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