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

View AU$231 flight on Tue, 2 Sep. 2025Opens in a new window

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

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

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
Sat, 8 Nov. - Sat, 15 Nov.
SEA
Seattle
IAD
Washington
AU$397 Return, found 5 days ago
AU$397
Return
found 5 days ago
Select Alaska Airlines flight, departing Sat, 8 Nov. from Seattle to Washington, returning Sat, 15 Nov., priced at AU$397 found 5 days ago
Delta
Sat, 8 Nov. - Sat, 15 Nov.
SEA
Seattle
IAD
Washington
AU$399 Return, found 5 days ago
AU$399
Return
found 5 days ago
Select Delta flight, departing Sat, 8 Nov. from Seattle to Washington, returning Sat, 15 Nov., priced at AU$399 found 5 days ago
Alaska Airlines
Thu, 4 Sep. - Wed, 10 Sep.
SEA
Seattle
IAD
Washington
AU$426 Return, found 10 hours ago
AU$426
Return
found 10 hours ago
Select Alaska Airlines flight, departing Thu, 4 Sep. from Seattle to Washington, returning Wed, 10 Sep., priced at AU$426 found 10 hours ago
Alaska Airlines
Thu, 25 Sep. - Wed, 1 Oct.
SEA
Seattle
IAD
Washington
AU$429 Return, found 4 days ago
AU$429
Return
found 4 days ago
Select Alaska Airlines flight, departing Thu, 25 Sep. from Seattle to Washington, returning Wed, 1 Oct., priced at AU$429 found 4 days ago
Delta
Thu, 25 Sep. - Wed, 1 Oct.
SEA
Seattle
IAD
Washington
AU$430 Return, found 4 days ago
AU$430
Return
found 4 days ago
Select Delta flight, departing Thu, 25 Sep. from Seattle to Washington, returning Wed, 1 Oct., priced at AU$430 found 4 days ago
Alaska Airlines
Fri, 19 Sep. - Fri, 26 Sep.
SEA
Seattle
IAD
Washington
AU$460 Return, found 6 days ago
AU$460
Return
found 6 days ago
Select Alaska Airlines flight, departing Fri, 19 Sep. from Seattle to Washington, returning Fri, 26 Sep., priced at AU$460 found 6 days ago
Alaska Airlines
Sat, 8 Nov. - Sat, 15 Nov.
SEA
Seattle
IAD
Washington
AU$461 Return, found 5 days ago
AU$461
Return
found 5 days ago
Select Alaska Airlines flight, departing Sat, 8 Nov. from Seattle to Washington, returning Sat, 15 Nov., priced at AU$461 found 5 days ago
American Airlines
Sat, 8 Nov. - Sat, 15 Nov.
SEA
Seattle
IAD
Washington
AU$475 Return, found 5 days ago
AU$475
Return
found 5 days ago
Select American Airlines flight, departing Sat, 8 Nov. from Seattle to Washington, returning Sat, 15 Nov., priced at AU$475 found 5 days ago
Delta
Thu, 4 Sep. - Wed, 10 Sep.
SEA
Seattle
IAD
Washington
AU$488 Return, found 10 hours ago
AU$488
Return
found 10 hours ago
Select Delta flight, departing Thu, 4 Sep. from Seattle to Washington, returning Wed, 10 Sep., priced at AU$488 found 10 hours ago
United
Sat, 8 Nov. - Sat, 15 Nov.
SEA
Seattle
IAD
Washington
AU$552 Return, found 5 days ago
AU$552
Return
found 5 days ago
Select United flight, departing Sat, 8 Nov. from Seattle to Washington, returning Sat, 15 Nov., priced at AU$552 found 5 days ago

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

September is typically the cheapest month to fly

From AU$291 - AU$458 per traveller.

Graph displaying average flight prices per month

Flight from Seattle to Washington route information
Origin airport
Seattle - Tacoma Intl.
Destination airport
Washington Dulles Intl.
Return price
AU$397
Distance
3679 km
Average flight time
8 hours 12 mins

Your quick guide to flights from Seattle to Washington

Pick up great flights from Seattle to Washington

With Expedia, you have your pick of 32 flights a day with 20 airlines covering flights from Seattle to Washington. 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 Seattle to Washington that take around 10 hours.

Find cheap flights from Seattle to Washington

From the great flight deals with prices currently ranging from AU$397 to AU$552, you can choose to see the cheapest flights first. Generally, you can book the cheapest flights from Seattle to Washington 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 Washington is normally in November.

Reasons to book your flight from Seattle to Washington 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 Seattle to Washington 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 Washington 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 Sea-Tac Airport to Washington Dulles Intl. Airport (IAD)?
The lowest price advertised for a round-trip journey between SEA and Washington Dulles Intl. Airport (IAD) is AU$397. But you better act quick. This price is based on fares quoted within the last 7 days on Expedia for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.
Do I need to pay a cancellation fee if I cancel my flight from Sea-Tac Airport to Washington Dulles Intl. Airport (IAD)?
Most flights can be cancelled online, but whether or not you incur a fee varies between airlines. If you do need to cancel your getaway, follow the instructions in the Customer Service Portal.
How do I find cheap flights from SEA to IAD 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 SEA to IAD flights, you'll see a "no change fees" filter for you to select.
How far is the flight from Sea-Tac Airport to Dulles Intl. Airport?
The flight distance between Sea-Tac Airport (SEA) and Washington Dulles Intl. Airport (IAD) (IAD) is 3 700 kilometres. Sneak in a nap or make a start on the latest bestseller and the trip will zip on by.
Which airlines fly direct from Seattle - Tacoma Intl. Airport (SEA) to Dulles Intl. Airport?
There are a few airlines that fly directly from Seattle - Tacoma Intl. Airport (SEA) to IAD. United Airlines (UA) is a great choice, offering 60 flights every month. Offering 56 flights every month along this route, Alaska Airlines (AS) is another good option.
Are SEA to Washington Dulles Intl. Airport (IAD) flight tickets cheaper when they're purchased at the last minute?
Booking last minute from Seattle - Tacoma Intl. Airport (SEA) to IAD can be hit-or-miss. You might be lucky and score a bargain, but you could also miss out completely! If you'd rather play it safe and start your travel planning early on, Expedia compares flight deals up to a year in advance. Just remember that not all airlines advertise their prices that far in advance. Our top tip? Check back often as prices are updated regularly.

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