Cheap flights from London Heathrow Airport to Washington, D.C. from £375

The cheapest month to fly to Washington, D.C. from London Heathrow Airport is in September. Flight prices, which tend to average around £489, are often lower during this time because this is during the off-season. If you don’t want to visit Washington, D.C. in September, then you should wait until February to fly from London Heathrow Airport, when ticket prices are also cheap, with an average price of £492.

On average, the least expensive day to fly to Washington, D.C. from London Heathrow Airport is on a Friday. momondo users have found tickets for Friday departures for as low as £563. However, this price may fluctuate depending on the airline, the season, and holidays. On the other hand, Sunday is the most expensive day to depart from London Heathrow Airport because it is more convenient for both business and leisure travellers. As a result, prices tend to be around £629.

At midday is the cheapest time of day to fly from London Heathrow Airport to Washington, D.C. when you can find flight prices for as low as £559. Flying to Washington, D.C. at midday is an ideal time because this is during off-peak travel hours. Flights to Washington, D.C. are more costly in the morning, with an average ticket price of £600. Departure times in the morning fall within the peak daily travel times, which is why tickets can be more expensive.

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

You are more likely to see cheaper flights to Washington, D.C. from London Heathrow Airport when booking weeks ahead of your departure date. In general, you can expect to find flights to Washington, D.C. for around £545 when searching weeks before you fly. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Washington, D.C. from London Heathrow Airport for as low as £484 on momondo.

There are 4 cabin classes available to choose from on London Heathrow Airport 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 9% on your flight if you consider stops on a London Heathrow Airport to Washington, D.C. flight.

As of October 2026, prices for London Heathrow Airport to Washington, D.C. flights are approximately 9% cheaper when compared to flights at the same time last year.

TAP AIR PORTUGAL, Austrian Airlines, and JetBlue are the most popular carriers operating from London Heathrow to Washington, D.C.

British Airways, Virgin Atlantic and Lufthansa are the top three most popular airlines that fly to Washington, D.C. from London Heathrow Airport according to our data. British Airways is the first choice among our users, with 42% of people opting to fly with this airline when travelling to Washington, D.C.. Keep in mind that there are 16 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 16% 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 140 minutes.

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

Saturday is statistically the day of the week that experiences the fewest 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 fewest delays on this route over the last 12 months, with about 10% of their flights experiencing any sort of delay.

Reykjavik (KEF) was the most common stop: 55% of momondo users choosing one-stop flights on this route connected there.

Flights via Lisbon (LIS) offer the lowest average return price of £343.

Flights connecting via New York (JFK) have the shortest average one-way travel time: 10h 59m.

Charlotte (CLT) has the shortest average stopover time for this route: 1h 06m.

As of October 2026, there are 12 flights per day flying from London Heathrow Airport to Washington, D.C.. The most common time of day flights depart is 16:00, with 100% of flights taking off in the afternoon.

86 flights are operational weekly from London Heathrow Airport to Washington, D.C. as of October 2026. The most popular departure day for this route is Thu, with 31% of flights per week taking off on this day.