Cheap Flights from Washington (IAD) to Seattle (SEA)

View AU$228 flight on Sat, 20 Sep. 2025Opens in a new window

Popular airlines from Washington Dulles International Airport (IAD) to Seattle-Tacoma International Airport (SEA)

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Cheap Flights from Washington (IAD) to Seattle (SEA)

Prices were available within the past 7 days for one-way flights and round trip tickets for the period specified. Prices and availability are subject to change. Additional terms apply.

Alaska Airlines
Tue, 9 Sep. - Tue, 16 Sep.
IAD
Washington
SEA
Seattle
AU$420 Return, found 5 days ago
AU$420
Return
found 5 days ago
Select Alaska Airlines flight, departing Tue, 9 Sep. from Washington to Seattle, returning Tue, 16 Sep., priced at AU$420 found 5 days ago
Delta
Tue, 9 Sep. - Tue, 16 Sep.
IAD
Washington
SEA
Seattle
AU$420 Return, found 5 days ago
AU$420
Return
found 5 days ago
Select Delta flight, departing Tue, 9 Sep. from Washington to Seattle, returning Tue, 16 Sep., priced at AU$420 found 5 days ago
Alaska Airlines
Tue, 26 Aug. - Tue, 2 Sep.
IAD
Washington
SEA
Seattle
AU$421 Return, found 5 days ago
AU$421
Return
found 5 days ago
Select Alaska Airlines flight, departing Tue, 26 Aug. from Washington to Seattle, returning Tue, 2 Sep., priced at AU$421 found 5 days ago
Delta
Tue, 26 Aug. - Tue, 2 Sep.
IAD
Washington
SEA
Seattle
AU$422 Return, found 5 days ago
AU$422
Return
found 5 days ago
Select Delta flight, departing Tue, 26 Aug. from Washington to Seattle, returning Tue, 2 Sep., priced at AU$422 found 5 days ago
Alaska Airlines
Tue, 9 Sep. - Tue, 16 Sep.
IAD
Washington
SEA
Seattle
AU$450 Return, found 5 days ago
AU$450
Return
found 5 days ago
Select Alaska Airlines flight, departing Tue, 9 Sep. from Washington to Seattle, returning Tue, 16 Sep., priced at AU$450 found 5 days ago
American Airlines
Tue, 26 Aug. - Tue, 2 Sep.
IAD
Washington
SEA
Seattle
AU$452 Return, found 5 days ago
AU$452
Return
found 5 days ago
Select American Airlines flight, departing Tue, 26 Aug. from Washington to Seattle, returning Tue, 2 Sep., priced at AU$452 found 5 days ago
Alaska Airlines
Tue, 9 Sep. - Tue, 16 Sep.
IAD
Washington
SEA
Seattle
AU$481 Return, found 5 days ago
AU$481
Return
found 5 days ago
Select Alaska Airlines flight, departing Tue, 9 Sep. from Washington to Seattle, returning Tue, 16 Sep., priced at AU$481 found 5 days ago
American Airlines
Tue, 26 Aug. - Tue, 2 Sep.
IAD
Washington
SEA
Seattle
AU$482 Return, found 5 days ago
AU$482
Return
found 5 days ago
Select American Airlines flight, departing Tue, 26 Aug. from Washington to Seattle, returning Tue, 2 Sep., priced at AU$482 found 5 days ago
Delta
Fri, 24 Oct. - Sun, 26 Oct.
IAD
Washington
SEA
Seattle
AU$496 Return, found 3 days ago
AU$496
Return
found 3 days ago
Select Delta flight, departing Fri, 24 Oct. from Washington to Seattle, returning Sun, 26 Oct., priced at AU$496 found 3 days ago
United
Tue, 26 Aug. - Tue, 2 Sep.
IAD
Washington
SEA
Seattle
AU$558 Return, found 5 days ago
AU$558
Return
found 5 days ago
Select United flight, departing Tue, 26 Aug. from Washington to Seattle, returning Tue, 2 Sep., priced at AU$558 found 5 days ago

Find the cheapest month to fly from Washington (IAD) to Seattle (SEA)

September is typically the cheapest month to fly

From AU$289 - AU$455 per traveller.

Graph displaying average flight prices per month

Flight from Washington to Seattle route information
Origin airport
Washington Dulles Intl.
Destination airport
Seattle - Tacoma Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, United
Return price
AU$420
Distance
3679 km
Average flight time
2 hours 48 mins

Your quick guide to flights from Washington to Seattle

Pick up great flights from Washington to Seattle

With Expedia, you have your pick of 31 flights a day with 20 airlines covering flights from Washington to Seattle. Whether you’re on a business trip, a family holiday or a luxury break, just enter your travel dates, hit search then check out your choice of flights. Select from return, one way or multi-city flights, and use the advance search tool if you want a direct or refundable flight. You can narrow your search to show you just your preferred cabin class and airline, too. It’s all easy. You can book direct flights from Washington to Seattle that take around 5 hours.

Find cheap flights from Washington to Seattle

From the great flight deals with prices currently ranging from AU$420 to AU$558, you can choose to see the cheapest flights first. Generally, you can book the cheapest flights from Washington to Seattle around 4 to 6 weeks in advance. If your travel dates are flexible, try to avoid weekends and peak seasons – when you are more likely to grab the lowest prices. Even last minute, there are some impressive deals. The cheapest time to fly to Seattle is normally in September.

Reasons to book your flight from Washington to Seattle with Expedia

Expedia makes it easy to find, book, and travel, with everything you need all in one place. When you enter your travel details, find fantastic deals just for you on flight tickets from Washington to Seattle across all the main airline carriers, so you can save time, dollars, and hassle finding the perfect flight. If you think your plans could change, choose refundable flights so any changes won’t cost you more. Book your flight to Seattle right now and, if you join Expedia Rewards, you earn points this time and every time you travel with Expedia.

Frequently asked questions

How much is a flight from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
Start packing your bags, because round-trip flights from IAD to Sea-Tac Airport start from AU$420. That's based on fares advertised within the last 7 days on Expedia for flights departing within the next year. Prices can change quickly, so book today to get the best deal. Prices and availability are subject to change. Additional terms apply.
Do I need to pay a cancellation fee if I cancel my flight from IAD to Sea-Tac Airport?
Most flights can be conveniently cancelled online, but whether you incur a fee differs between airlines. If you do need to cancel your holiday, follow the instructions in the Customer Service Portal.
How do I find cheap flights from Dulles Intl. Airport to Seattle - Tacoma Intl. Airport (SEA) that have flexible change policies?
Many airlines offer the option to reschedule your flight without a change fee. All you pay is the difference between the original flight and the new flight. When you're searching for Dulles Intl. Airport to Seattle - Tacoma Intl. Airport (SEA) flights, you'll see a "no change fees" filter for you to select.
How far is the flight from Dulles Intl. Airport to Seattle - Tacoma Intl. Airport (SEA)?
You'll be in the air for a while, as the flight distance between Chantilly and SeaTac is 3 700 kilometres. Set up a playlist of your favourite songs before leaving home to keep yourself entertained during your trip.
Which airlines fly direct from Washington Dulles Intl. Airport (IAD) to SEA?
United Airlines (UA) is a popular option. It offers 60 flights from IAD to Sea-Tac Airport each month. Offering 56 flights a month along this route, Alaska Airlines (AS) is another top pick.
Are IAD to Sea-Tac Airport flight tickets cheaper when they're purchased at the last minute?
It is possible to find a fantastic last-minute deal from IAD to Seattle - Tacoma Intl. Airport (SEA), but it can also be hit-or-miss. As many airlines release seats up to 12 months in advance, it's worthwhile keeping an eye on fares early and being ready to pounce when you see a good bargain. Expedia compares air carrier prices and updates flight deals frequently, so you can rest assured you're always seeing the latest offers.

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