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Cheap flights from Washington, D.C. Dulles Intl Airport to St. Louis from $62

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 1/8. 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.
United Airlines Logo
8:40 am - 10:13 am
IAD
-
STL
2h 33mnonstop
United Airlines Logo
8:30 am - 11:40 am
STL
-
IAD
2h 10mnonstop
$265United Airlines
Tue, Jan 13 - Tue, Jan 20
Frontier Logo
10:03 am - 10:33 pm
IAD
-
STL
13h 30m1 stop
Frontier Logo
9:35 am - 7:40 am
STL
-
IAD
21h 05m1 stop
$267Frontier
Sat, Jan 10 - Sun, Jan 11
Multiple Airlines Logo
2:58 pm - 11:19 pm
IAD
-
STL
9h 21m2 stops
Multiple Airlines Logo
11:32 am - 12:31 am
STL
-
IAD
11h 59m1 stop
$269Multiple Airlines
Mon, Mar 9 - Wed, Mar 11
United Airlines Logo
5:38 pm - 11:59 pm
IAD
-
STL
7h 21m1 stop
United Airlines Logo
8:30 am - 11:40 am
STL
-
IAD
2h 10mnonstop
$271United Airlines
Thu, Jan 15 - Sun, Jan 18
United Airlines Logo
11:10 am - 12:37 pm
IAD
-
STL
2h 27mnonstop
United Airlines Logo
12:44 pm - 3:55 pm
STL
-
IAD
2h 11mnonstop
$273United Airlines
Tue, Jan 6 - Mon, Jan 12
United Airlines Logo
1:05 pm - 5:43 pm
IAD
-
STL
5h 38m1 stop
United Airlines Logo
8:30 am - 11:40 am
STL
-
IAD
2h 10mnonstop
$275United Airlines
Wed, Jan 14 - Thu, Jan 15
United Airlines Logo
8:40 am - 10:13 am
IAD
-
STL
2h 33mnonstop
United Airlines Logo
8:30 am - 11:40 am
STL
-
IAD
2h 10mnonstop
$278United Airlines
Wed, Feb 18 - Sat, Feb 21
United Airlines Logo
8:20 am - 12:29 pm
IAD
-
STL
5h 09m1 stop
United Airlines Logo
9:57 am - 5:35 pm
STL
-
IAD
6h 38m1 stop
$281United Airlines
Thu, Jan 15 - Sun, Jan 18
United Airlines Logo
5:17 pm - 10:58 pm
IAD
-
STL
6h 41m1 stop
United Airlines Logo
8:30 am - 11:40 am
STL
-
IAD
2h 10mnonstop
$282United Airlines
Fri, Jan 16 - Sun, Jan 18
United Airlines Logo
11:10 am - 12:37 pm
IAD
-
STL
2h 27mnonstop
United Airlines Logo
8:05 am - 4:00 pm
STL
-
IAD
6h 55m1 stop
$283United Airlines
Tue, Jan 6 - Mon, Jan 12

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 25
IAD5:50 pmWashington, D.C. Dulles Intl
2h 32m
STL7:22 pmLambert-St Louis
Jan 1
STL8:15 amLambert-St Louis
2h 09m
IAD11:24 amWashington, D.C. Dulles Intl
$262
Find similar
United Airlines
Jan 13
IAD8:40 amWashington, D.C. Dulles Intl
2h 33m
STL10:13 amLambert-St Louis
Jan 20
STL8:30 amLambert-St Louis
2h 10m
IAD11:40 amWashington, D.C. Dulles Intl
$265
Find similar
United Airlines
Jan 15
IAD5:38 pmWashington, D.C. Dulles Intl
7h 21m
1 stop
STL11:59 pmLambert-St Louis
Jan 18
STL8:30 amLambert-St Louis
2h 10m
IAD11:40 amWashington, D.C. Dulles Intl
$271
Find similar

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
Jan 10
IAD10:03 amWashington, D.C. Dulles Intl
13h 30m
1 stop
STL10:33 pmLambert-St Louis
Jan 11
STL9:35 amLambert-St Louis
21h 05m
1 stop
IAD7:40 amWashington, D.C. Dulles Intl
$267
Find similar
Frontier
Dec 29
IAD9:58 pmWashington, D.C. Dulles Intl
25h 35m
1 stop
STL10:33 pmLambert-St Louis
Jan 1
STL10:42 amLambert-St Louis
6h 34m
1 stop
IAD6:16 pmWashington, D.C. Dulles Intl
$294
Find similar
Frontier
Mar 6
IAD2:39 pmWashington, D.C. Dulles Intl
23h 24m
1 stop
STL1:03 pmLambert-St Louis
Mar 8
STL7:42 amLambert-St Louis
22h 42m
1 stop
IAD7:24 amWashington, D.C. Dulles Intl
$301
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 December 18, 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

Tue 1/13

8:40 am-10:13 am

Nonstop2h 33m

Lambert-St Louis

Tue 1/20

8:30 am-11:40 am

Nonstop2h 10m

$265

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sat 1/10

10:03 am-10:33 pm

1 stop13h 30m

Lambert-St Louis

Sun 1/11

9:35 am-7:40 am

1 stop21h 05m

$267

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Mon 3/9

2:58 pm-11:19 pm

2 stops9h 21m

Lambert-St Louis

Wed 3/11

11:32 am-12:31 am

1 stop11h 59m

$269

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Thu 1/15

5:38 pm-11:59 pm

1 stop7h 21m

Lambert-St Louis

Sun 1/18

8:30 am-11:40 am

Nonstop2h 10m

$271

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Tue 1/6

11:10 am-12:37 pm

Nonstop2h 27m

Lambert-St Louis

Mon 1/12

12:44 pm-3:55 pm

Nonstop2h 11m

$273

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Wed 1/14

1:05 pm-5:43 pm

1 stop5h 38m

Lambert-St Louis

Thu 1/15

8:30 am-11:40 am

Nonstop2h 10m

$275

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Wed 2/18

8:40 am-10:13 am

Nonstop2h 33m

Lambert-St Louis

Sat 2/21

8:30 am-11:40 am

Nonstop2h 10m

$278

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Thu 1/15

8:20 am-12:29 pm

1 stop5h 09m

Lambert-St Louis

Sun 1/18

9:57 am-5:35 pm

1 stop6h 38m

$281

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Fri 1/16

5:17 pm-10:58 pm

1 stop6h 41m

Lambert-St Louis

Sun 1/18

8:30 am-11:40 am

Nonstop2h 10m

$282

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Tue 1/6

11:10 am-12:37 pm

Nonstop2h 27m

Lambert-St Louis

Mon 1/12

8:05 am-4:00 pm

1 stop6h 55m

$283

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 Saturday when prices can be found for as low as $344. 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 $409. 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 $380 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 $393 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 10% 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 December 2025, prices for Washington, D.C. Dulles Intl Airport to St. Louis flights are approximately 39% 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

$234

Fastest flight time

2h 28m

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 $234. 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 $349.
The fastest flight from Washington, D.C. Dulles Intl Airport to St. Louis takes 2h 28m
Direct flights go from Washington, D.C. Dulles Intl Airport to St. Louis every day.
There is 1 airport in St. Louis. From Washington, D.C. Dulles Intl Airport there are direct flights to 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 28m.

  • 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 $78Free CancellationRating
5.8
3,081 reviews
Search Frontier flights
DeltaPriceFrom $149Free CancellationRating
7.9
8,005 reviews
Search Delta flights
United AirlinesPriceFrom $246Free CancellationRating
7.4
9,092 reviews
Search United Airlines flights
American AirlinesPriceFrom $254Free CancellationRating
7.2
11,055 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 6 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 $246 round-trip, up to an average price of $456. 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
Maryland Heights
O'Fallon
Florissant
Fenton
Wentzville
St. Peters
Collinsville
Alton
Clayton
Festus
Glencoe
Farmington
Eureka
Edwardsville
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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