Cheap Flights from SEA to IAD: When to Fly from Seattle to Washington

The cheapest times to fly from SEA to IAD are

• January 1st to March 4th
• April 16th to May 6th
• August 27th to November 18th

based on data collected exclusively by Champion Traveler across tens of millions of flights. Among all the dates above, the very cheapest time to fly from SEA to IAD is late October. Prices can be as high as $973 for Sunday flights during late July, or as low as $247 for Tuesday flights around late October.

When to Fly to Washington

Flying from Seattle, WA (SEA) to Washington, DC (IAD) will usually cost between $263 to $527 per person if booking more than four weeks in advance. On average the very cheapest time to fly is late October with an average ticket price of $285. Due to high demand the most expensive time to fly is late July, with an average price of $527. Planning your trip to low-cost times can easily save you $242 on economy flights and even more on first-class flights. Generally, any price below $360 can be considered a good price for a round-trip SEA to IAD flight.

See below for a graph of average weekly prices for the SEA to IAD route. All prices are for round-trip tickets in USD.

Compared to other flights, the SEA to IAD flight is much cheaper than the average and costs much less than the average flight leaving from Seattle. The average price per mile (for a direct flight) is $0.1, which is far below average.

Flight Prices by Day of the Week

Tuesday is usually the cheapest day to depart and return on this flight. Sundays are the most expensive days to fly out or take a return trip. Selecting flights on the least expensive days could save you up to $137 (31%) on this flight.

Departing prices are for round-trip flights returning on the day of departure. For example, a flight departing on Tuesday and returning a week later will cost an average of $304. Return trip prices are from the IAD to SEA flight, and often highlight the quality of our data in showing the same trend.

Nonstop Flights and Layovers

Travelers looking to fly from SEA to IAD can generally find a 0-layover flight. Because there is a direct flight option the real-world direct flight time of 5 hour 7 minutes may be realistic.

Alternative Nearby Airports

Champion Traveler tells you which airports are nearby and whether tickets might be cheaper alternative airports nearby. Sometimes it’s worth it to fly into a closer airport and then commute to your destination. Remember that there is a nonstop flight from SEA to IAD while comparing.

Flight Questions Answered

Still have questions about flying from SEA to IAD? We’ve got answers.

Which airlines fly this route?

You can find 10 major airlines flying this route most often: Alaska, American, China Eastern, Delta, Fiji Airways, Frontier, Singapore Airlines, Southwest, Sun Country Airlines, United, and potentially more during busy seasons.

How far away is it from Washington Dulles International Airport to Seattle/Tacoma International Airport?

The distance between the two airports is roughly 2299 miles or 3700 kilometers.

How long does it take to fly from SEA to IAD?

The real-world flight time for a nonstop SEA to IAD flight is about 5 hour 7 minutes.

How many flights go between Seattle, WA and Washington, DC?

It depends on the day of the week and the date, but a typical day might have around 86 available flights from SEA to IAD.

Airport Location Info

Late and Early Flight Data

Flights from SEA to IAD tend to depart as late as the average flight. According to our recently updated data, 29% of flights departed 5 or more minutes late, and 23% of flights left 5 or more minutes early. On average you can expect to leave IAD heading for SEA about 11 minutes late. This does significantly impact arrival time, as the average landing time in Washington, DC is about 10 minutes late. The numbers below show a recent average of take-off times versus the scheduled departure flight:

• Delta: 2 minutes early
• United: 13 minutes late
• Alaska: 12 minutes late
• Some airlines not reporting

Please note that while we’ve worked hard to analyzed tens of millions of flights to get you this data, we do not calculate current live prices or guarantee pricing. Please see our partners using the links above for current offers.