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Cheap flights from Washington, D.C. Dulles Intl Airport to St. Louis from $55

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Washington, D.C. Dulles Intl Airport to St. Louis departing on 12/4. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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Find the cheapest flights from Washington, D.C. Dulles Intl Airport to St. Louis

Cheap round-trip flights

Enter your travel dates to find the best prices.
Frontier Logo
12:47 pm - 10:14 amIAD-STL
46h 27m2 stops
Frontier Logo
10:47 am - 5:25 pmSTL-IAD
5h 38m1 stop
$225Frontier
Find Deal
Mon, Dec 1 - Mon, Dec 8
Frontier Logo
3:37 pm - 10:33 pmIAD-STL
7h 56m1 stop
Frontier Logo
7:43 pm - 4:32 pmSTL-IAD
19h 49m2 stops
$228Frontier
Find Deal
Fri, Feb 20 - Wed, Feb 25
Frontier Logo
6:00 am - 4:01 pmIAD-STL
11h 01m1 stop
Frontier Logo
2:12 pm - 7:52 pmSTL-IAD
28h 40m1 stop
$229Frontier
Find Deal
Fri, Nov 14 - Sun, Nov 16
Frontier Logo
6:00 am - 10:12 amIAD-STL
5h 12m1 stop
Frontier Logo
11:05 am - 7:51 pmSTL-IAD
7h 46m1 stop
$231Frontier
Find Deal
Thu, Nov 13 - Fri, Nov 14
Frontier Logo
6:00 am - 10:12 amIAD-STL
5h 12m1 stop
Frontier Logo
7:45 pm - 8:20 pmSTL-IAD
23h 35m2 stops
$235Frontier
Find Deal
Sun, Nov 16 - Tue, Nov 18
United Airlines Logo
8:40 am - 10:07 amIAD-STL
2h 27mnonstop
United Airlines Logo
8:30 am - 11:40 amSTL-IAD
2h 10mnonstop
$263United Airlines
Find Deal
Sat, Dec 6 - Tue, Dec 9
United Airlines Logo
8:20 am - 2:25 pmIAD-STL
7h 05m1 stop
United Airlines Logo
8:30 am - 11:40 amSTL-IAD
2h 10mnonstop
$273United Airlines
Find Deal
Tue, Dec 2 - Tue, Dec 9
Delta Logo
5:59 pm - 9:57 pmIAD-STL
4h 58m1 stop
Delta Logo
9:30 am - 5:00 pmSTL-IAD
6h 30m1 stop
$283Delta
Find Deal
Tue, Dec 2 - Tue, Dec 9
American Airlines Logo
6:00 am - 5:05 pmIAD-STL
12h 05m1 stop
American Airlines Logo
9:58 am - 11:28 pmSTL-IAD
12h 30m2 stops
$329American Airlines
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Sun, Feb 15 - Wed, Feb 18
Delta Logo
6:00 am - 9:59 amIAD-STL
4h 59m1 stop
Delta Logo
6:09 pm - 11:03 pmSTL-IAD
3h 54m1 stop
$332Delta
Find Deal
Thu, Nov 27 - Mon, Dec 1

Delta flights from Washington, D.C. Dulles Intl Airport to St. Louis

Our best Delta deals on Washington, D.C. Dulles Intl Airport to St. Louis flight tickets
Delta
Dec 2
IAD5:59 pmWashington, D.C. Dulles Intl
4h 58m
1 stop
STL9:57 pmLambert-St Louis
Dec 9
STL9:30 amLambert-St Louis
6h 30m
1 stop
IAD5:00 pmWashington, D.C. Dulles Intl
$283
Find similar
Delta
Nov 27
IAD6:00 amWashington, D.C. Dulles Intl
4h 59m
1 stop
STL9:59 amLambert-St Louis
Dec 1
STL6:09 pmLambert-St Louis
3h 54m
1 stop
IAD11:03 pmWashington, D.C. Dulles Intl
$332
Find similar
Delta
Nov 11
IAD6:00 amWashington, D.C. Dulles Intl
4h 46m
1 stop
STL9:46 amLambert-St Louis
Nov 15
STL11:39 amLambert-St Louis
4h 25m
1 stop
IAD5:04 pmWashington, D.C. Dulles Intl
$711
Find similar

United Airlines flights from Washington, D.C. Dulles Intl Airport to St. Louis

Our best United Airlines deals on Washington, D.C. Dulles Intl Airport to St. Louis flight tickets
United Airlines
Dec 6
IAD8:40 amWashington, D.C. Dulles Intl
2h 27m
STL10:07 amLambert-St Louis
Dec 9
STL8:30 amLambert-St Louis
2h 10m
IAD11:40 amWashington, D.C. Dulles Intl
$263
Find similar
United Airlines
Dec 2
IAD8:20 amWashington, D.C. Dulles Intl
7h 05m
1 stop
STL2:25 pmLambert-St Louis
Dec 9
STL8:30 amLambert-St Louis
2h 10m
IAD11:40 amWashington, D.C. Dulles Intl
$273
Find similar
United Airlines
Dec 4
IAD8:40 amWashington, D.C. Dulles Intl
2h 27m
STL10:07 amLambert-St Louis
Dec 8
STL8:30 amLambert-St Louis
2h 10m
IAD11:40 amWashington, D.C. Dulles Intl
$299
Find similar

momondo Fare Finder

 
Customize your flight search to find flights from Washington, D.C. Dulles Intl Airport to St. Louis that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, momondo users made 832,500 searches. Data last updated November 3, 2025.
Use the filters below to find and compare flights from Washington, D.C. Dulles Intl Airport to St. Louis that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Mon 12/1

12:47 pm-10:14 am

2 stops46h 27m

Lambert-St Louis

Mon 12/8

10:47 am-5:25 pm

1 stop5h 38m

$225

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Fri 2/20

3:37 pm-10:33 pm

1 stop7h 56m

Lambert-St Louis

Wed 2/25

7:43 pm-4:32 pm

2 stops19h 49m

$228

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Fri 11/14

6:00 am-4:01 pm

1 stop11h 01m

Lambert-St Louis

Sun 11/16

2:12 pm-7:52 pm

1 stop28h 40m

$229

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Thu 11/13

6:00 am-10:12 am

1 stop5h 12m

Lambert-St Louis

Fri 11/14

11:05 am-7:51 pm

1 stop7h 46m

$231

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sun 11/16

6:00 am-10:12 am

1 stop5h 12m

Lambert-St Louis

Tue 11/18

7:45 pm-8:20 pm

2 stops23h 35m

$235

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sat 12/6

8:40 am-10:07 am

Nonstop2h 27m

Lambert-St Louis

Tue 12/9

8:30 am-11:40 am

Nonstop2h 10m

$263

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Tue 12/2

8:20 am-2:25 pm

1 stop7h 05m

Lambert-St Louis

Tue 12/9

8:30 am-11:40 am

Nonstop2h 10m

$273

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Tue 12/2

5:59 pm-9:57 pm

1 stop4h 58m

Lambert-St Louis

Tue 12/9

9:30 am-5:00 pm

1 stop6h 30m

$283

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sun 2/15

6:00 am-5:05 pm

1 stop12h 05m

Lambert-St Louis

Wed 2/18

9:58 am-11:28 pm

2 stops12h 30m

$329

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Thu 11/27

6:00 am-9:59 am

1 stop4h 59m

Lambert-St Louis

Mon 12/1

6:09 pm-11:03 pm

1 stop3h 54m

$332

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to St. Louis from

How to get the cheapest flight ticket from Washington, D.C. Dulles Intl Airport to St. Louis

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the typical price of a round-trip flight between Washington, D.C. Dulles Intl Airport and St. Louis?

What is the cheapest month to fly to St. Louis?

In general, August is the cheapest month to fly from Washington, D.C. Dulles Intl Airport to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $290. The month of July is another great option to travel to St. Louis, with average flight prices from Washington, D.C. Dulles Intl Airport averaging around $292.

What is the cheapest day to depart on your flight to St. Louis?

The cheapest day to depart on your flight to St. Louis is on a Tuesday when prices can be found for as low as $331. This is often the case because there is less demand to fly during this day of the week. If your travel schedule is flexible, try to avoid departing on a Sunday because tickets tend to average around $427. These prices are subject to change though, so be sure to set up a Price Alert for flights to St. Louis.

What is the cheapest time of day to depart on your flight to St. Louis?

Flying to St. Louis from Washington, D.C. Dulles Intl Airport in the evening is the least expensive time of day to depart. momondo users have found prices as low as $312 when looking at flights departing in the evening. In the afternoon is when there is more demand to fly to St. Louis, so prices are often more expensive at around $385 per ticket.

What is the cheapest Washington, D.C. Dulles Intl to Lambert-St Louis flight route?

Fly from Washington, D.C. Dulles Intl to Lambert-St Louis for the best Washington, D.C. Dulles Intl - Lambert-St Louis flight prices

How far in advance should I book a flight to St. Louis?

You are more likely to see cheaper flights to St. Louis from Washington, D.C. Dulles Intl Airport when booking weeks ahead of your departure date. In general, you can expect to find flights to St. Louis for around $398 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to St. Louis from Washington, D.C. Dulles Intl Airport for as low as $260 on momondo.

What cabin class options are available on Washington, D.C. Dulles Intl to Lambert-St Louis flights?

There are 4 cabin classes available to choose from on Washington, D.C. Dulles Intl to Lambert-St Louis flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Can stopping save me money on Washington, D.C. Dulles Intl Airport to St. Louis flights?

You could potentially save up to 33% on your flight if you consider stops on a Washington, D.C. Dulles Intl Airport to St. Louis flight.

How have Washington, D.C. Dulles Intl Airport to St. Louis flight prices changed over time?

As of November 2025, prices for Washington, D.C. Dulles Intl Airport to St. Louis flights are approximately 11% cheaper when compared to flights at the same time last year.

When to book flights from Washington, D.C. Dulles Intl Airport to St. Louis

Are you open to changing your travel dates? Check out the ideal times to fly from Washington, D.C. Dulles Intl Airport to St. Louis according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap Washington, D.C. Dulles Intl Airport to St. Louis (IAD to STL) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Washington, D.C. Dulles Intl Airport to St. Louis

Best Price Found

$149

Fastest flight time

2h 23m

Direct flights

Every day

Airports in St. Louis

1 airport
The best one-way flight to St. Louis from Washington, D.C. Dulles Intl Airport in the past 72 hours is $149. The best round-trip flight deal from Washington, D.C. Dulles Intl Airport to St. Louis found on momondo in the last 72 hours is $335.
The fastest flight from Washington, D.C. Dulles Intl Airport to St. Louis takes 2h 23m
Direct flights go from Washington, D.C. Dulles Intl Airport to St. Louis every day.
There is 1 airport near St. Louis: Lambert-St Louis (STL)
Search flight deals

  • How far is Washington, D.C. Dulles Intl to Lambert-St Louis by plane?

    The straight-line distance from Washington, D.C. Dulles Intl to Lambert-St Louis is 685.9 mi. By plane, this route typically takes 2h 26m.

  • When did momondo last update prices for flights from Washington, D.C. Dulles Intl Airport to Lambert-St Louis Airport?

    Prices for flights from Washington, D.C. Dulles Intl Airport to Lambert-St Louis Airport are updated daily.

  • How many operators does momondo search for flights from Washington, D.C. Dulles Intl Airport to Lambert-St Louis Airport?

  • How old do you have to be to fly from Washington, D.C. Dulles Intl Airport to Lambert-St Louis Airport?

    The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Washington, D.C. Dulles Intl Airport to Lambert-St Louis Airport.

  • What documentation or ID do you need to fly to Lambert-St Louis Airport?

    The travel and health documents required for your trip to Lambert-St Louis Airport can vary based on your itinerary and personal situation. As a rule, consider having multiple documents such as a national ID card or driver’s license, and a passport valid for six-months after you plan to arrive at Lambert-St Louis Airport. We always recommend checking with your airline or a trusted third party such as IATA to get advice.

  • What is the most popular plane model from Washington, D.C. Dulles Intl Airport to St. Louis?

  • What is the most popular airline from Washington, D.C. Dulles Intl Airport to St. Louis?

Best airlines flying from Washington, D.C. Dulles Intl Airport to St. Louis

Compare and see reviews for airlines that fly from Washington, D.C. Dulles Intl Airport to St. Louis with momondo
Airline
Rating
Free Cancellation
Price
FrontierPriceFrom $130Free CancellationRating
5.8
3,117 reviews
Search Frontier flights
DeltaPriceFrom $149Free CancellationRating
7.9
8,002 reviews
Search Delta flights
United AirlinesPriceFrom $248Free CancellationRating
7.4
8,997 reviews
Search United Airlines flights
American AirlinesPriceFrom $276Free CancellationRating
7.2
11,038 reviews
Search American Airlines flights

  • United Airlines Flights From Washington, D.C. Dulles Intl Airport to St. Louis

    United Airlines is one of the most popular airlines flying from Washington, D.C. Dulles Intl Airport to St. Louis, operating 14 flights/week on average for this route. A good United Airlines flight deal for Washington, D.C. Dulles Intl Airport to St. Louis starts from $248 round-trip, up to an average price of $466. Our users have rated United Airlines at 7.4/10.

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
St. Charles
Chesterfield
Hermann
Fairview Heights
Florissant
Maryland Heights
O'Fallon
Wentzville
Fenton
Collinsville
St. Peters
Alton
Farmington
Festus
Glencoe
Edwardsville
Clayton
Eureka
Litchfield
Shrewsbury

Why use momondo?

Why should I use momondo to find a flight deal from Washington, D.C. to St. Louis?

It is quick and easy to find Washington, D.C. to St. Louis flights on momondo. We search and return numerous flight options from various airlines and agents. You can then use our filters to narrow your search until you have found the most convenient flight to St. Louis that suits you.

Can I find flights from Washington, D.C. to St. Louis with flexible booking policies on momondo?

Yes. All flights to St. Louis from Washington, D.C. on momondo can be compared and filtered by various policies on offer, including flexible booking.

How can momondo help me find flights from Washington, D.C. to St. Louis?

momondo provides multiple filters to help you find the best flight to St. Louis from Washington, D.C.. Filter by price, airline, airports, cabin, aircraft, payment method, number of stops and more.

I’m not ready to book a flight from Washington, D.C. to St. Louis right now. Can momondo alert me if prices change?

Yes momondo offers price alerts on flights to St. Louis from Washington, D.C.. After performing a search on this page you should be able to see the price alert set up feature. Simply provide a valid email address and momondo will instantly alert you when prices change.

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