Cheap flights from St. Louis to Washington, D.C. from $93

The month of October is, on average, the cheapest month to fly to Washington, D.C. Reagan-National Airport from St. Louis, with most prices found around $317. If you aren’t able to travel to Washington, D.C. Reagan-National Airport during the month of October, then flying in September is also cheap. Prices for this month can be found on momondo for an average of $325.

The cheapest day to depart from St. Louis to Washington, D.C. Reagan-National Airport is on a Saturday. Travelers who choose to depart for Washington, D.C. Reagan-National Airport on a Saturday will often find tickets for as low as $354. Flights from St. Louis to Washington, D.C. Reagan-National Airport on a Sunday will generally be more expensive and average around $438. Keep in mind that these prices on both days could fluctuate depending on the season and the demand.

Our data shows that the cheapest St. Louis to Washington, D.C. Reagan-National Airport flights are usually those with departure times at noon. Our users have found flights to Washington, D.C. Reagan-National Airport at noon for as low as $353. In contrast, the most expensive time of day to depart to Washington, D.C. Reagan-National Airport is in the evening when prices are around $397.

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

You are more likely to see cheaper flights to Washington, D.C. Reagan-National Airport from St. Louis when booking weeks ahead of your departure date. In general, you can expect to find flights to Washington, D.C. Reagan-National Airport for around $384 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Washington, D.C. Reagan-National Airport from St. Louis for as low as $265 on momondo.

There are 3 cabin classes available to choose from on St. Louis to Washington, D.C. Reagan-National Airport flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

You could potentially save up to 4% on your flight if you consider stops on a St. Louis to Washington, D.C. Reagan-National Airport flight.

As of August 2026, prices for St. Louis to Washington, D.C. Reagan-National Airport flights are approximately 13% more expensive when compared to flights at the same time last year.

Southwest and Delta are the most popular carriers operating from Lambert-St Louis to Washington, D.C. Reagan-National

Southwest, American Airlines and Frontier are the top three most popular airlines that fly to Washington, D.C. Reagan-National Airport from St. Louis according to our data. Southwest is the first choice among our users, with 63% of people opting to fly with this airline when traveling to Washington, D.C. Reagan-National Airport. Keep in mind that there are 3 different airlines that fly to Washington, D.C. Reagan-National Airport on a routine basis, so you have a few additional options to choose from.

As of August 2026, there are 4 flights per day flying from St. Louis to Washington, D.C. Reagan-National Airport. The most common time of day flights depart is 6:00AM, with 45% of flights taking off at noon.

29 flights are operational weekly from St. Louis to Washington, D.C. Reagan-National Airport as of August 2026. The most popular departure day for this route is Mon, with 24% of flights per week taking off on this day.