For quick check-in at IAD, locate your airline’s counter by walking around the first row. Counters are like an island with desks on both sides.

Most accurate provider | eDreams 3 stars |
|---|---|
Most trusted provider | eDreams 3 stars |
Round-trip from | $225 (CheapOair) |
One-way from | $55 (Frontier) |
Popular in | September |
Cheapest in | August |
Average price | $466 |
Good round-trip deal | $335 or less |
Good one-way deal | $149 or less |
Fly from
Fly to
Route
Depart
Return
Price
Washington, D.C.St. Louis
IAD - STL
IADSTL
Washington, D.C. Dulles Intl
Wed 12/17
7:01 am-10:45 am
1 stop4h 44m
Lambert-St Louis
Tue 1/20
5:56 pm-11:06 pm
1 stop4h 10m
Washington, D.C.St. Louis
IAD - STL
IADSTL
Washington, D.C. Dulles Intl
Fri 11/21
8:35 am-11:57 pm
1 stop16h 22m
Lambert-St Louis
Sat 11/22
9:52 am-11:59 pm
2 stops13h 07m
Washington, D.C.St. Louis
IAD - STL
IADSTL
Washington, D.C. Dulles Intl
Wed 12/17
8:20 am-2:25 pm
1 stop7h 05m
Lambert-St Louis
Wed 1/14
8:30 am-11:40 am
Nonstop2h 10m
Washington, D.C.St. Louis
IAD - STL
IADSTL
Washington, D.C. Dulles Intl
Wed 12/17
8:20 am-12:15 pm
1 stop4h 55m
Lambert-St Louis
Tue 1/20
8:30 am-11:40 am
Nonstop2h 10m
Washington, D.C.St. Louis
IAD - STL
IADSTL
Washington, D.C. Dulles Intl
Sun 12/28
8:15 am-12:27 pm
1 stop5h 12m
Lambert-St Louis
Fri 1/9
12:44 pm-3:55 pm
Nonstop2h 11m
Washington, D.C.St. Louis
IAD - STL
IADSTL
Washington, D.C. Dulles Intl
Sat 12/6
5:45 pm-7:13 pm
Nonstop2h 28m
Lambert-St Louis
Mon 12/8
8:30 am-11:40 am
Nonstop2h 10m
Washington, D.C.St. Louis
IAD - STL
IADSTL
Washington, D.C. Dulles Intl
Thu 11/27
12:36 pm-6:35 pm
1 stop6h 59m
Lambert-St Louis
Mon 12/1
6:09 pm-11:03 pm
1 stop3h 54m
Washington, D.C.St. Louis
IAD - STL
IADSTL
Washington, D.C. Dulles Intl
Sun 12/28
8:35 am-10:08 am
Nonstop2h 33m
Lambert-St Louis
Sat 1/10
8:30 am-11:40 am
Nonstop2h 10m
Washington, D.C.St. Louis
IAD - STL
IADSTL
Washington, D.C. Dulles Intl
Fri 12/5
8:40 am-10:07 am
Nonstop2h 27m
Lambert-St Louis
Sun 12/7
6:30 am-11:49 am
1 stop4h 19m
Washington, D.C.St. Louis
IAD - STL
IADSTL
Washington, D.C. Dulles Intl
Fri 12/12
12:30 pm-5:56 pm
1 stop6h 26m
Lambert-St Louis
Sun 12/14
9:30 am-5:00 pm
1 stop6h 30m
| Provider | Price Accuracy | Trust Score* |
|---|---|---|
| Price Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*1 star | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy1 star | Trust Score*3 stars |
The best time to book flights from Washington, D.C. Dulles Intl Airport to St. Louis is 69 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.
Currently, October is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to St. Louis (average of $139). Flying from Washington, D.C. Dulles Intl Airport to St. Louis in January is currently the most expensive (average of $302). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.
It’s typically best to fly out from Washington, D.C. Dulles Intl Airport to St. Louis in the evening. Doing so could potentially save you 38% on the flight price compared to flying in the afternoon, which is usually more expensive.
Food
Boarding
Comfort
Overall
Crew
Entertainment
Reviews
Jim,Nov 2025
AVL - ATL
Food
Boarding
Comfort
Overall
Crew
Entertainment
Reviews
Jim,Nov 2025
AVL - ATL
Food
Boarding
Comfort
Overall
Crew
Entertainment
Reviews
Jim,Nov 2025
AVL - ATL
Food
Boarding
Comfort
Overall
Crew
Entertainment
Reviews
Jim,Nov 2025
AVL - ATL
Food
Boarding
Comfort
Overall
Crew
Entertainment
Reviews
Jim,Nov 2025
AVL - ATL
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$130 | Average$221 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$149 | Average$304 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$248 | Average$466 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$276 | Average$387 | FlexibilityNo cancel fee | On-time71% |