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Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from £154

IAD — SEA
3 Nov — 10 Nov1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Dulles Intl to Seattle

Enter your travel dates to find the best prices.

Cheapest flights from Dulles Intl to Seattle

Tue 3/1107:46 -
Nonstop5h 50m
Tue 3/1113:03 -
1 stop25h 37m
Deal found 1/10£262
Fri 30/1021:06 -
2 stops21h 06m
Thu 5/1120:09 -
2 stops18h 03m
Deal found 30/9£265
Mon 16/1117:17 -
Nonstop5h 56m
Mon 23/1108:15 -
Nonstop4h 58m
Deal found 2/10£267
Thu 5/1117:17 -
Nonstop5h 56m
Sun 8/1108:07 -
Nonstop5h 07m
Deal found 30/9£282
Thu 5/1107:46 -
Nonstop5h 50m
Mon 9/1121:49 -
Nonstop4h 55m
Deal found 29/9£283
Sat 5/1215:14 -
1 stop9h 44m
Thu 10/1208:09 -
Nonstop4h 59m
Deal found 1/10£289
Fri 6/1117:17 -
Nonstop5h 56m
Mon 9/1120:48 -
1 stop17h 52m
Deal found 30/9£292
Fri 30/1006:15 -
1 stop9h 03m
Thu 5/1112:47 -
1 stop7h 43m
Deal found 30/9£299
Fri 6/1107:05 -
Nonstop5h 51m
Mon 9/1116:30 -
Nonstop4h 50m
Deal found 30/9£300

Find flight deals from Dulles Intl to Seattle

Round-trip from

£262

One-way from

£154

Popular in

June

Cheapest in

January

Average price

£356
Alaska Airlines
  • Alaska Airlines
  • 30/1-31/1
  • 1 total stop
  • 14h 23m total
  • Washington, D.C. to Seattle
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Alaska Airlines
  • Alaska Airlines
  • 18/11-31/12
  • 1 total stop
  • 17h 41m total
  • Washington, D.C. to Seattle
Search Deals
Highest demand for flights based on searches. 19% potential increase in price (£55 potential increase over avg. return price).
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Cheapest flight prices on average. 3% potential price decrease (£8 potential savings vs. average return price).
Search Deals
Average for round-trip flights in October 2026
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Cheapflights Fare Finder

 
Use the filters below to find and compare flights from Washington, D.C. Dulles Intl Airport to Seattle that are best for you.

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Depart

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Price

Cheapest return flight

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Wed 18/11

18:46-09:27

1 stop17h 41m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£154

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Fri 22/1

17:35-20:42

Nonstop6h 07m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£158

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Sun 6/12

17:55-21:01

Nonstop6h 06m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£158

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Sun 6/12

17:18-20:27

Nonstop6h 09m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£158

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Sat 23/1

15:45-21:56

1 stop9h 11m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£162

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Fri 4/12

15:14-21:58

1 stop9h 44m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£162

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Fri 6/11

17:29-23:20

1 stop8h 51m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£165

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Thu 14/1

17:30-20:33

Nonstop6h 03m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£177

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Wed 31/3

17:25-23:57

1 stop9h 32m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£196

Washington, D.C.Seattle

IAD Washington, D.C. Dulles Intl - SEA Seattle/Tacoma Intl

IADSEA

Washington, D.C. Dulles Intl

Fri 27/11

13:15-19:03

1 stop8h 48m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£196

Flights are sorted by cheapest return flights first.

Deals found on 2/10

Showing 1-10 of 22 resultsSorted by cheapest first
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Best time to book a flight from Dulles Intl to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from Dulles Intl with our price prediction graph.
Estimated return price

Cheapflights Insights

Everything you need to know about your flight from Washington, D.C. Dulles Intl Airport to Seattle

How far ahead should I book a flight from Washington, D.C. Dulles Intl Airport to Seattle?

The best time to book flights from Washington, D.C. Dulles Intl Airport to Seattle is 54 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.

What is the cheapest month to book a flight from Washington, D.C. Dulles Intl Airport to Seattle?

Currently, January is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to Seattle (average of £171). Flying from Washington, D.C. Dulles Intl Airport to Seattle in June is currently the most expensive (average of £408). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from IAD to SEA?

When flying from Washington, D.C. Dulles Intl Airport to Seattle, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

How much does it cost for a return flight from Washington, D.C. Dulles Intl Airport to Seattle?

Airfare is below average for this route at the moment.

Washington, D.C. Dulles Intl Airport to Seattle flights typically cost between £282 and £502 in November.
The cheapest return price found within the last 5 days was £262 on Alaska Airlines (3 Nov–3 Nov).

Related info for your journey

  • What airport do you fly into for flights to Seattle from Washington, D.C. Dulles Intl?

    Located just 11.4 mi from the city center, Seattle/Tacoma Intl is the airport most travelers will use when flying to Seattle from Washington, D.C. Dulles Intl. Booking flights from Washington, D.C. Dulles Intl to Seattle/Tacoma Intl (SEA) should be relatively easy as there are 10 daily inbound flights from Washington, D.C. Dulles Intl from 0 different airlines.

  • How long is the flight from Washington, D.C. Dulles Intl Airport to Seattle?

    Alaska Airlines and United Airlines can get you from Washington, D.C. Dulles Intl Airport to Seattle in just under 6h 03m. Your travel time can differ by up to 4h 13m. The distance from Washington, D.C. Dulles Intl Airport to Seattle is about 2299 mi. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.

  • What are the most reliable airlines from Washington, D.C. Dulles Intl Airport to Seattle?

    The top 3 most reliable airlines when flying from Washington, D.C. Dulles Intl Airport to Seattle are Finnair (93%), Japan Airlines (85%) and Alaska Airlines (84%).

  • Can I find deals for flights from Dulles Intl to Seattle that include hotel bookings?

    Yes. In addition to deals on Dulles Intl to Seattle flights, Cheapflights offers holiday packages that include both flights and hotel.

  • How can I find direct flights from Dulles Intl to Seattle?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Dulles Intl to Seattle.

  • Can I find deals for business class flights from Dulles Intl to Seattle?

    Yes. Cheapflights offers flight deals from Dulles Intl to Seattle by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Washington, D.C. Dulles Intl Airport to Seattle?

    Currently, January is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to Seattle (average of £171). Flying from Washington, D.C. Dulles Intl Airport to Seattle in June is currently the most expensive (average of £408). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

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Need flexible booking options for your flight to Seattle from Dulles Intl? Don’t worry, Cheapflights have you covered. Use our search filter to only show flights with no change fees.

Can Cheapflights notify me if prices for flights from Dulles Intl to Seattle become cheaper?

Yes, Cheapflights offers price alerts on Dulles Intl to Seattle flights so you can book your travel at the perfect time. Price Alerts can be enabled by clicking the bell icon next to the flight deals above and providing your email address where you want to receive the alerts.

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