Cheap flights from St. Louis to Washington, D.C. from $79
This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from St. Louis to Washington, D.C. departing on 8/26. 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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Southwest flights from St. Louis to Washington, D.C. Dulles Intl Airport
Our best Southwest deals on St. Louis to Washington, D.C. Dulles Intl Airport flight tickets
United Airlines flights from St. Louis to Washington, D.C. Dulles Intl Airport
Our best United Airlines deals on St. Louis to Washington, D.C. Dulles Intl Airport flight tickets
See travel insights to Washington, D.C. from
How to get the cheapest flight ticket from St. Louis to Washington, D.C. Dulles Intl Airport
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 Washington, D.C. Dulles Intl Airport?
In general, August is the cheapest month to fly from St. Louis to Washington, D.C. Dulles Intl Airport. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $294. If you aren’t able to travel to Washington, D.C. Dulles Intl Airport during the month of August, then flying in January is also cheap. Prices for this month can be found on momondo for an average of $299.
What is the cheapest day to depart on your flight to Washington, D.C. Dulles Intl Airport?
Our data shows that Friday is the least expensive day to fly to Washington, D.C. Dulles Intl Airport. Tickets to fly out on this day can be as low as $736. When flying out on a Saturday, the most expensive travel day of the week, you can expect to see flight prices from St. Louis to Washington, D.C. Dulles Intl Airport for around $1,163.
What is the cheapest time of day to depart on your flight to Washington, D.C. Dulles Intl Airport?
Flying to Washington, D.C. Dulles Intl Airport from St. Louis in the evening is the least expensive time of day to depart. momondo users have found prices as low as $262 when looking at flights departing in the evening. If you have a flexible travel schedule, then try to avoid flying at noon when prices are $1,196 on average. Flights to Washington, D.C. Dulles Intl Airport from St. Louis at noon are generally more expensive because this time of day is more convenient for travelers’ schedules.
What is the cheapest Lambert-St Louis to Washington, D.C. Dulles Intl flight route?
Fly from Lambert-St Louis to Washington, D.C. Dulles Intl for the best Lambert-St Louis - Washington, D.C. Dulles Intl flight prices
How far in advance should I book a flight to Washington, D.C. Dulles Intl Airport?
You are more likely to see cheaper flights to Washington, D.C. Dulles Intl Airport from St. Louis when booking 14 weeks ahead of your departure date. In general, you can expect to find flights to Washington, D.C. Dulles Intl Airport for around $378 when searching 14 weeks out.However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Washington, D.C. Dulles Intl Airport from St. Louis for as low as $249 on momondo.
What cabin class options are available on Lambert-St Louis to Washington, D.C. Dulles Intl flights?
There are 4 cabin classes available to choose from on Lambert-St Louis to Washington, D.C. Dulles Intl 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 St. Louis to Washington, D.C. Dulles Intl Airport flights?
No. A direct flight is the cheapest option for a flight between St. Louis to Washington, D.C. Dulles Intl Airport.
How have St. Louis to Washington, D.C. Dulles Intl Airport flight prices changed over time?
As of June 2025, prices for St. Louis to Washington, D.C. Dulles Intl Airport flights are approximately 2% cheaper when compared to flights at the same time last year.
What is the cheapest airline that flies from Lambert-St Louis to Washington, D.C. Dulles Intl?
United Airlines, Southwest, and Delta are the most popular carriers operating from Lambert-St Louis to Washington, D.C. Dulles Intl
What airlines fly to Washington, D.C. Dulles Intl Airport?
United Airlines, Delta and American Airlines are the top three most popular airlines that fly to Washington, D.C. Dulles Intl Airport from St. Louis according to our data. United Airlines is the first choice among our users, with 70% of people opting to fly with this airline when traveling to Washington, D.C. Dulles Intl Airport. Keep in mind that there are 3 different airlines that fly to Washington, D.C. Dulles Intl Airport on a routine basis, so you have a few additional options to choose from.
How many flights depart from St. Louis to Washington, D.C. Dulles Intl Airport on average per day?
6 flights are operational daily from St. Louis to Washington, D.C. Dulles Intl Airport as of June 2025. The most popular departure time for this route is 8:00AM, with 55% of flights per day taking off at noon.
How many flights depart from St. Louis to Washington, D.C. Dulles Intl Airport on average per week?
The number of flights available between St. Louis and Washington, D.C. Dulles Intl Airport is 47 per week as of June 2025. The most frequent departure day is Mon, with 15% of weekly flights leaving on this day.
When to book flights from St. Louis to Washington, D.C. Dulles Intl Airport
Cheap St. Louis to Washington, D.C. Dulles Intl Airport (STL to IAD) flight deals and tips
Find info about flight duration, direct flights, and airports for your flight from St. Louis to Washington, D.C. Dulles Intl Airport
How far is Lambert-St Louis to Washington, D.C. Dulles Intl by plane?
The straight-line distance from Lambert-St Louis to Washington, D.C. Dulles Intl is 685.9 mi. Flights usually cover this in 2h 06m, depending on flying conditions and air traffic around both airports.
When did momondo last update prices for flights from Lambert-St Louis Airport to Washington, D.C. Dulles Intl Airport?
Prices for flights from Lambert-St Louis Airport to Washington, D.C. Dulles Intl Airport are refreshed on a daily basis.
How many operators does momondo search for flights from Lambert-St Louis Airport to Washington, D.C. Dulles Intl Airport?
The number of operators available for flights from Lambert-St Louis Airport to Washington, D.C. Dulles Intl Airport is 3 as of June 2025.
How old do you have to be to fly from Lambert-St Louis Airport to Washington, D.C. Dulles Intl Airport?
Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Lambert-St Louis Airport to Washington, D.C. Dulles Intl Airport.
What documentation or ID do you need to fly to Washington, D.C. Dulles Intl Airport?
The necessary travel and health documents for your Washington, D.C. Dulles Intl Airport trip may vary depending on your travel plans and individual circumstances. Generally, you should have various documents, such as a national ID card or driver's license and a passport that is valid for six months beyond your scheduled arrival date. We recommend seeking advice from your airline or a trusted third party, such as IATA.
What is the most popular plane model from St. Louis to Washington, D.C. Dulles Intl Airport?
Based on momondo bookings for flights between St. Louis and Washington, D.C. Dulles Intl Airport, the leading plane model is Canadair (Bombardier) Regional Jet CRJ-550, making up 59.18% of the total bookings. Other popular models include Canadair (Bombardier) Regional Jet 900 with 5.10%, Embraer 175 (Enhanced Winglets) with 4.08%, and Embraer 175 with 4.08%.
What is the most popular airline from St. Louis to Washington, D.C. Dulles Intl Airport?
Based on momondo bookings for this flight route, the most popular airline on flight routes from St. Louis to Washington, D.C. Dulles Intl Airport is United Airlines (70% of total bookings). The next most popular airlines are Delta (24%) and American Airlines (6%).
Best airlines flying from St. Louis to Washington, D.C. Dulles Intl Airport
Compare and see reviews for airlines that fly from St. Louis to Washington, D.C. Dulles Intl Airport with momondo
| Airline | Rating | Free Cancellation | Price | ||
|---|---|---|---|---|---|
| PriceFrom $129 | Free Cancellation | Rating 7.2 10,000 reviews | |||
| PriceFrom $191 | Free Cancellation | Rating 8.0 7,946 reviews | |||
| PriceFrom $209 | Free Cancellation | Rating 7.4 8,790 reviews |
United Airlines Flights From St. Louis to Washington, D.C. Dulles Intl Airport
United Airlines flight deals from St. Louis to Washington, D.C. Dulles Intl Airport start from $209 round-trip. Over the 14 United Airlines flights for this route in a normal week, average airfare is usually $421 round-trip - but some users have found much cheaper deals with momondo.
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Why should I use momondo to find a flight deal from St. Louis to Washington, D.C.?
We help find the flight that best suits your needs, momondo compares prices from hundreds of airlines and travel agents and helps you filter them to find the best flight from St. Louis to Washington, D.C. for you.
Can I find flights from St. Louis to Washington, D.C. with flexible booking policies on momondo?
Yes. momondo allows you to filter the results for St. Louis to Washington, D.C. flights to just show those with flexible booking policies.
How can momondo help me find flights from St. Louis to Washington, D.C.?
momondo offers useful filters to help you find the right flight. Choose specific flight times, airports or even what payment method you prefer. We have numerous options to help you book your ideal flight from St. Louis to Washington, D.C..
I’m not ready to book a flight from St. Louis to Washington, D.C. right now. Can momondo alert me if prices change?
Yes. momondo can track prices for St. Louis to Washington, D.C. flights and alert you when they change. Perform a search to set up the price alert. All that is required is a valid email address.