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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 12/15. 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
9:20 pm - 8:59 amIAD-STL
12h 39m1 stop
Frontier Logo
4:27 pm - 9:03 pmSTL-IAD
27h 36m1 stop
$243Frontier
Find Deal
Sat, Dec 13 - Sat, Dec 20
Frontier Logo
5:35 am - 9:40 amIAD-STL
5h 05m1 stop
Frontier Logo
10:42 am - 6:16 pmSTL-IAD
6h 34m1 stop
$245Frontier
Find Deal
Thu, Dec 25 - Thu, Dec 25
Delta Logo
7:01 am - 10:45 amIAD-STL
4h 44m1 stop
Delta Logo
11:40 am - 5:03 pmSTL-IAD
4h 23m1 stop
$255Delta
Find Deal
Tue, Dec 2 - Wed, Dec 3
Frontier Logo
7:01 pm - 9:40 amIAD-STL
15h 39m1 stop
Frontier Logo
5:11 pm - 11:28 amSTL-IAD
17h 17m2 stops
$258Frontier
Find Deal
Wed, Dec 31 - Wed, Jan 7
Frontier Logo
6:55 am - 2:29 pmIAD-STL
8h 34m1 stop
Frontier Logo
3:14 pm - 11:59 pmSTL-IAD
7h 45m1 stop
$261Frontier
Find Deal
Thu, Nov 20 - Sun, Nov 23
Frontier Logo
11:12 am - 11:57 pmIAD-STL
13h 45m1 stop
Frontier Logo
4:13 pm - 7:45 amSTL-IAD
14h 32m1 stop
$264Frontier
Find Deal
Thu, Nov 20 - Mon, Nov 24
Frontier Logo
9:00 am - 10:33 pmIAD-STL
14h 33m2 stops
Frontier Logo
10:40 am - 9:03 pmSTL-IAD
9h 23m1 stop
$265Frontier
Find Deal
Tue, Dec 16 - Mon, Jan 5
Delta Logo
12:58 pm - 4:28 pmIAD-STL
4h 30m1 stop
Delta Logo
9:59 am - 5:17 pmSTL-IAD
6h 18m1 stop
$269Delta
Find Deal
Wed, Dec 31 - Wed, Jan 7
Frontier Logo
11:20 am - 6:19 pmIAD-STL
7h 59m1 stop
Frontier Logo
3:14 pm - 11:59 pmSTL-IAD
7h 45m1 stop
$272Frontier
Find Deal
Mon, Nov 24 - Tue, Nov 25
United Airlines Logo
8:40 am - 10:13 amIAD-STL
2h 33mnonstop
United Airlines Logo
8:05 am - 4:00 pmSTL-IAD
6h 55m1 stop
$275United Airlines
Find Deal
Thu, Jan 22 - Sat, Jan 24

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

Our best Frontier deals on Washington, D.C. Dulles Intl Airport to St. Louis flight tickets
Frontier
Nov 24
IAD6:55 amWashington, D.C. Dulles Intl
12h 24m
2 stops
STL6:19 pmLambert-St Louis
Nov 27
STL3:14 pmLambert-St Louis
7h 45m
1 stop
IAD11:59 pmWashington, D.C. Dulles Intl
$241
Find similar
Frontier
Dec 13
IAD9:20 pmWashington, D.C. Dulles Intl
12h 39m
1 stop
STL8:59 amLambert-St Louis
Dec 20
STL4:27 pmLambert-St Louis
27h 36m
1 stop
IAD9:03 pmWashington, D.C. Dulles Intl
$243
Find similar
Frontier
Dec 25
IAD5:35 amWashington, D.C. Dulles Intl
5h 05m
1 stop
STL9:40 amLambert-St Louis
Dec 25
STL10:42 amLambert-St Louis
6h 34m
1 stop
IAD6:16 pmWashington, D.C. Dulles Intl
$245
Find similar

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
IAD7:01 amWashington, D.C. Dulles Intl
4h 44m
1 stop
STL10:45 amLambert-St Louis
Dec 3
STL11:40 amLambert-St Louis
4h 23m
1 stop
IAD5:03 pmWashington, D.C. Dulles Intl
$255
Find similar
Delta
Dec 31
IAD12:58 pmWashington, D.C. Dulles Intl
4h 30m
1 stop
STL4:28 pmLambert-St Louis
Jan 7
STL9:59 amLambert-St Louis
6h 18m
1 stop
IAD5:17 pmWashington, D.C. Dulles Intl
$269
Find similar
Delta
Jan 28
IAD6:00 amWashington, D.C. Dulles Intl
4h 39m
1 stop
STL9:39 amLambert-St Louis
Jan 30
STL5:56 pmLambert-St Louis
4h 10m
1 stop
IAD11:06 pmWashington, D.C. Dulles Intl
$296
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 17, 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

Sat 12/13

9:20 pm-8:59 am

1 stop12h 39m

Lambert-St Louis

Sat 12/20

4:27 pm-9:03 pm

1 stop27h 36m

$243

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Thu 12/25

5:35 am-9:40 am

1 stop5h 05m

Lambert-St Louis

Thu 12/25

10:42 am-6:16 pm

1 stop6h 34m

$245

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Tue 12/2

7:01 am-10:45 am

1 stop4h 44m

Lambert-St Louis

Wed 12/3

11:40 am-5:03 pm

1 stop4h 23m

$255

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Wed 12/31

7:01 pm-9:40 am

1 stop15h 39m

Lambert-St Louis

Wed 1/7

5:11 pm-11:28 am

2 stops17h 17m

$258

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Thu 11/20

6:55 am-2:29 pm

1 stop8h 34m

Lambert-St Louis

Sun 11/23

3:14 pm-11:59 pm

1 stop7h 45m

$261

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Thu 11/20

11:12 am-11:57 pm

1 stop13h 45m

Lambert-St Louis

Mon 11/24

4:13 pm-7:45 am

1 stop14h 32m

$264

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Tue 12/16

9:00 am-10:33 pm

2 stops14h 33m

Lambert-St Louis

Mon 1/5

10:40 am-9:03 pm

1 stop9h 23m

$265

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Wed 12/31

12:58 pm-4:28 pm

1 stop4h 30m

Lambert-St Louis

Wed 1/7

9:59 am-5:17 pm

1 stop6h 18m

$269

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Mon 11/24

11:20 am-6:19 pm

1 stop7h 59m

Lambert-St Louis

Tue 11/25

3:14 pm-11:59 pm

1 stop7h 45m

$272

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Thu 1/22

8:40 am-10:13 am

Nonstop2h 33m

Lambert-St Louis

Sat 1/24

8:05 am-4:00 pm

1 stop6h 55m

$275

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 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 $336. 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 $425. 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 $315 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 $384 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 $405 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 $191 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 35% 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 27m.

  • 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
3,106 reviews
Search Frontier flights
DeltaPriceFrom $149Free CancellationRating
7.9
8,007 reviews
Search Delta flights
United AirlinesPriceFrom $248Free CancellationRating
7.4
9,013 reviews
Search United Airlines flights
American AirlinesPriceFrom $276Free CancellationRating
7.2
11,050 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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