Cheap flights from Washington, D.C. to London from £262

In general, August is the cheapest month to fly from Washington, D.C. to London Heathrow Airport. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around £497. The month of September is another great option to travel to London Heathrow Airport, with average flight prices from Washington, D.C. averaging around £500.

On average, the least expensive day to fly to London Heathrow Airport from Washington, D.C. is on a Tuesday. momondo users have found tickets for Tuesday departures for as low as £560. However, this price may fluctuate depending on the airline, the season, and holidays. Be sure to avoid booking your departure on a Friday as prices are generally higher than usual. According to our data, the average ticket price to London Heathrow Airport on Friday is £616.

According to our data, the cheapest time of day to fly to London Heathrow Airport is in the afternoon. momondo users have found flights departing from Washington, D.C. to London Heathrow Airport in the afternoon for as low as £552. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. If you have a flexible travel schedule, then try to avoid flying in the evening when prices are £598 on average. Flights to London Heathrow Airport from Washington, D.C. in the evening are generally more expensive because this time of day is more convenient for travellers’ schedules.

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

You are more likely to see cheaper flights to London Heathrow Airport from Washington, D.C. when booking weeks ahead of your departure date. In general, you can expect to find flights to London Heathrow Airport for around £583 when searching weeks before you fly. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to London Heathrow Airport from Washington, D.C. for as low as £549 on momondo.

There are 4 cabin classes available to choose from on Washington, D.C. to London Heathrow 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 25% on your flight if you consider stops on a Washington, D.C. to London Heathrow Airport flight.

As of April 2026, prices for Washington, D.C. to London Heathrow Airport flights are approximately 2% more expensive when compared to flights at the same time last year.

JetBlue, British Airways, and United Airlines are the most popular carriers operating from Washington, D.C. to London Heathrow

British Airways, Virgin Atlantic and United Airlines are the top three most popular airlines that fly to London Heathrow Airport from Washington, D.C. according to our data. British Airways is the first choice among our users, with 52% of people opting to fly with this airline when travelling to London Heathrow Airport. Keep in mind that there are 7 different airlines that fly to London Heathrow Airport on a routine basis, so you have a few additional options to choose from.

Historically, on average around 19% of flights between Washington, D.C. and London have experienced a delay on any given week. The average delay length over the past 12 months has been 165 minutes.

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

Monday is statistically the day of the week that experiences the fewest delays on this flight route. Friday has historically seen more delays on average compared to the rest of the week.

According to our data, Virgin Atlantic have had the fewest delays on this route over the last 12 months, with about 15% of their flights experiencing any sort of delay.

Reykjavik (KEF) was the most common stop: 80% of momondo users choosing one-stop flights on this route connected there.

Flights via Reykjavik (KEF) offer the lowest average return price of £547.

Flights connecting via Dublin (DUB) have the shortest average one-way travel time: 9h 50m.

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

31 flights are operational daily from Washington, D.C. to London Heathrow Airport as of April 2026. The most popular departure time for this route is 18:00, with 100% of flights per day taking off in the evening.

218 flights are operational weekly from Washington, D.C. to London Heathrow Airport as of April 2026. The most popular departure day for this route is Thu, with 15% of flights per week taking off on this day.