An Alaska Airlines plane taking off with a snow-capped mountain in the background.

£127 Cheap Flights from Washington (IAD) to Seattle (SEA)

Flight 1

Photo by Port of Seattle
Open Photo by Port of Seattle

Cheap Flights from Washington to Seattle (IAD-SEA)

Prices were available within the past 7 days and start at £127 for one-way flights and £223 for return, for the period specified. Prices and availability are subject to change.
Delta
Thu, 3 Dec - Thu, 10 Dec
IAD
Washington
SEA
Seattle
From £223
Return
Found 6 days ago
Select Delta flight, departing Thu, 3 Dec from Washington to Seattle, returning Thu, 10 Dec, priced at £223 Found 6 days ago
Alaska Airlines
Thu, 3 Dec - Wed, 9 Dec
IAD
Washington
SEA
Seattle
From £224
Return
Found 4 days ago
Select Alaska Airlines flight, departing Thu, 3 Dec from Washington to Seattle, returning Wed, 9 Dec, priced at £224 Found 4 days ago
Delta
Thu, 3 Dec - Thu, 10 Dec
IAD
Washington
SEA
Seattle
From £230
Return
Found 6 days ago
Select Delta flight, departing Thu, 3 Dec from Washington to Seattle, returning Thu, 10 Dec, priced at £230 Found 6 days ago
Delta
Sat, 12 Dec - Tue, 15 Dec
IAD
Washington
SEA
Seattle
From £231
Return
Found 5 days ago
Select Delta flight, departing Sat, 12 Dec from Washington to Seattle, returning Tue, 15 Dec, priced at £231 Found 5 days ago
American Airlines
Thu, 3 Dec - Thu, 10 Dec
IAD
Washington
SEA
Seattle
From £237
Return
Found 6 days ago
Select American Airlines flight, departing Thu, 3 Dec from Washington to Seattle, returning Thu, 10 Dec, priced at £237 Found 6 days ago
Delta
Sat, 12 Dec - Tue, 15 Dec
IAD
Washington
SEA
Seattle
From £238
Return
Found 5 days ago
Select Delta flight, departing Sat, 12 Dec from Washington to Seattle, returning Tue, 15 Dec, priced at £238 Found 5 days ago
Alaska Airlines
Thu, 3 Dec - Thu, 10 Dec
IAD
Washington
SEA
Seattle
From £245
Return
Found 6 days ago
Select Alaska Airlines flight, departing Thu, 3 Dec from Washington to Seattle, returning Thu, 10 Dec, priced at £245 Found 6 days ago
Alaska Airlines
Wed, 16 Dec - Wed, 23 Dec
IAD
Washington
SEA
Seattle
From £254
Return
Found 4 days ago
Select Alaska Airlines flight, departing Wed, 16 Dec from Washington to Seattle, returning Wed, 23 Dec, priced at £254 Found 4 days ago
American Airlines
Thu, 3 Dec - Thu, 10 Dec
IAD
Washington
SEA
Seattle
From £260
Return
Found 6 days ago
Select American Airlines flight, departing Thu, 3 Dec from Washington to Seattle, returning Thu, 10 Dec, priced at £260 Found 6 days ago
United
Sat, 12 Dec - Tue, 15 Dec
IAD
Washington
SEA
Seattle
From £321
Return
Found 5 days ago
Select United flight, departing Sat, 12 Dec from Washington to Seattle, returning Tue, 15 Dec, priced at £321 Found 5 days ago

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

October is typically the cheapest month to fly

From £149 - £365 per traveller.

Book with confidence

Compare flights from Washington to Seattle easily and book with confidence

For travelling on business or for pleasure, Expedia makes it easy to book your flights from Washington to Seattle. Operating between them 4 flights per day, 4 airlines cover the route. And United Airlines, Delta Air Lines, Alaska Airlines fly direct, getting you to Seattle - Tacoma Intl. in just 5hours. If you have a preferred carrier, use our advanced search tool to find the right flight from Washington Dulles Intl. to Seattle - Tacoma Intl..

To make things even better, in the advanced search, you can also choose to fly economy, premium economy, business or first class, select your maximum number of stops, and pick your preferred departure and arrival time. You can also opt for refundable and direct flights.

Grab a great deal on your flight from Washington Dulles Intl. (IAD) to Seattle - Tacoma Intl. (SEA)

The easiest way to view the best deals on flights from Washington to Seattle today is to enter your travel dates and hit search. From here, you can sort your results by price to see the cheapest flights first. Right now, return flights from Washington Dulles Intl. to Seattle - Tacoma Intl. start at just £223 and range up to £321.

To find an even better deal, try

  • being flexible on your dates – midweek flights can be cheaper
  • looking for other airports near Washington and Seattle
  • booking your flight during December, the cheapest month on this route
  • varying your flight times – early morning and late at night are sometimes cheaper

Why you should book your Washington to Seattle flight with Expedia!

We cater for all flight types, cabin classes and airlines. So whether you’re booking flights from Washington Dulles Intl. to Seattle - Tacoma Intl. for a budget break or a business trip with a bit of pleasure thrown in, we make it easy to secure the seat that’s right for you.

Thanks to our supersized inventory that offers great choice all in one place, you know you’ll get a great deal with Expedia. Especially if you bundle your flight together with your hotel, you will unlock amazing savings. For added peace of mind, you can choose flexible bookings or filter to find refundable options, so you won’t pay a fee to change your flight.

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 £223. 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.

Travel information

Origin airport
Washington Dulles International Airport
Destination airport
Seattle-Tacoma International Airport
Distance
2,299 miles away
Airlines serving
Alaska Airlines, Delta, American Airlines, United, Sun Country Airlines, Frontier Airlines
Popular airline
Alaska Airlines
Return price
£223
Average flight time
5 hours 56 mins
*Available to Expedia members.