Cheap flights from London to Washington, D.C. from $437

The month of September is, on average, the cheapest month to fly to Washington, D.C. from London, with most prices found around $597. If you’re not able to fly to Washington, D.C. in September, then March is your next best option. Flight prices from London to Washington, D.C. during March average around $640.

On average, the least expensive day to fly to Washington, D.C. from London is on a Thursday. momondo users have found tickets for Thursday departures for as low as $744. However, this price may fluctuate depending on the airline, the season, and holidays. When flying out on a Sunday, the most expensive travel day of the week, you can expect to see flight prices from London to Washington, D.C. for around $908.

In the afternoon is the cheapest time of day to fly from London to Washington, D.C. when you can find flight prices for as low as $792. Flying to Washington, D.C. in the afternoon is an ideal time because this is during off-peak travel hours. Try not to purchase tickets in the morning because they tend to be around $810. Of course, these prices can vary depending on the time of year and what airport you fly to.

Fly from London Heathrow to Washington, D.C. Dulles Intl for the best London - Washington, D.C. flight prices

You are more likely to see cheaper flights to Washington, D.C. from London when booking weeks ahead of your departure date. In general, you can expect to find flights to Washington, D.C. for around $725 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Washington, D.C. from London for as low as $662 on momondo.

There are 4 cabin classes available to choose from on London to Washington, D.C. 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 36% on your flight if you consider stops on a London to Washington, D.C. flight.

As of July 2026, prices for London to Washington, D.C. flights are approximately 10% cheaper when compared to flights at the same time last year.

British Airways, Delta, and Virgin Atlantic are the most popular carriers operating from London to Washington, D.C.

British Airways, Lufthansa and American Airlines are the top three most popular airlines that fly to Washington, D.C. from London according to our data. British Airways is the first choice among our users, with 54% of people opting to fly with this airline when traveling to Washington, D.C.. Keep in mind that there are 10 different airlines that fly to Washington, D.C. on a routine basis, so you have a few additional options to choose from.

Historically, on average around 18% of flights between London and Washington, D.C. have experienced a delay on any given week. The average delay length over the past 12 months has been 137 minutes.

Generally, flights departing in the evening tend to experience fewer delays. Flights in the morning have, in the past, seen delays more frequently in comparison.

Saturday is statistically the day of the week which experiences the fewest number of delays on this flight route. Thursday has historically seen more delays on average compared to the rest of the week.

According to our data, United Airlines have had the least number of delays on this route over the last 12 months; with about 11% of their flights experiencing any sort of delay.

Dublin (DUB) was the most common stop: 48% of momondo users choosing 1-stop flights on this route connected there.

Flights via Boston (BOS) offer the lowest average round-trip price of $436.

Flights connecting via Dublin (DUB) have the shortest average one-way travel time: 10h 50m.

Reykjavik (KEF) has the shortest average layover time for this route: 1h 10m.

The number of flights available between London and Washington, D.C. is 32 per day as of July 2026. The most frequent departure time is 12:00PM, with 100% of daily flights leaving in the afternoon.

228 flights are operational weekly from London to Washington, D.C. as of July 2026. The most popular departure day for this route is Mon, with 14% of flights per week taking off on this day.