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Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from £156

IAD — SEA
29 Nov — 6 Dec1
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

Thu 3/1207:00 -
Nonstop6h 10m
Wed 9/1216:30 -
Nonstop5h 01m
Deal found 30/10£222
Wed 9/1215:14 -
1 stop9h 44m
Mon 14/1208:09 -
Nonstop4h 59m
Deal found 28/10£226
Thu 3/1207:00 -
Nonstop6h 10m
Sun 6/1223:59 -
1 stop8h 40m
Deal found 30/10£229
Sat 5/1215:14 -
1 stop9h 44m
Sat 12/1210:40 -
1 stop8h 17m
Deal found 30/10£233
Wed 2/1219:06 -
1 stop7h 47m
Tue 8/1222:40 -
1 stop7h 36m
Deal found 30/10£237
Tue 8/1207:00 -
Nonstop6h 05m
Tue 15/1220:09 -
1 stop18h 30m
Deal found 29/10£244
Sat 5/1207:00 -
Nonstop6h 05m
Mon 7/1221:15 -
2 stops17h 24m
Deal found 28/10£246
Sun 6/1207:00 -
Nonstop6h 05m
Thu 10/1221:40 -
Nonstop4h 55m
Deal found 28/10£252
Mon 7/1215:14 -
1 stop9h 44m
Thu 10/1208:09 -
Nonstop4h 59m
Deal found 29/10£256

Find flight deals from Dulles Intl to Seattle

Round-trip from

£222

One-way from

£156

Popular in

June

Cheapest in

January

Average price

£353
Alaska Airlines
  • Alaska Airlines
  • 11/12-14/12
  • Nonstop
  • 11h 09m total
  • Washington, D.C. to Seattle
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Delta
  • Delta
  • 9/1-31/12
  • Nonstop
  • 6h 01m total
  • Washington, D.C. to Seattle
Search Deals
Highest demand for flights based on searches. 17% potential increase in price (£50 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease (£7 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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Route

Depart

Return

Price

Cheapest return flight

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Mon 8/2

18:53-09:26

1 stop17h 33m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£167
Fastest return journey

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Mon 8/2

07:00-10:01

Nonstop6h 01m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£171

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Thu 7/1

17:55-21:02

Nonstop6h 07m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£171

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Mon 25/1

07:00-10:01

Nonstop6h 01m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£171

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Sun 6/12

07:00-10:10

Nonstop6h 10m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£171

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Mon 25/1

15:15-21:59

1 stop9h 44m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£175

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Tue 1/12

08:07-14:36

1 stop9h 29m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£193

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Tue 1/12

17:55-21:01

Nonstop6h 06m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£201

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Mon 21/12

08:50-11:57

Nonstop6h 07m

Seattle/Tacoma Intl

Wed 31/12

00:00-03:00

Nonstop0h 00m

£211

Washington, D.C.Seattle

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

IADSEA

Washington, D.C. Dulles Intl

Sat 5/12

07:00-10:10

Nonstop6h 10m

Seattle/Tacoma Intl

Sat 12/12

11:55-19:59

Nonstop5h 04m

£222

Flights are sorted by cheapest return flights first.

Deals found on 26/10

Showing 1-10 of 20 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 £169). Flying from Washington, D.C. Dulles Intl Airport to Seattle in June is currently the most expensive (average of £404). 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 £318 and £432 in December.
The cheapest return price found within the last 5 days was £222 on Delta (3 Dec–9 Dec).

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 3 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?

    Delta and United Airlines can get you from Washington, D.C. Dulles Intl Airport to Seattle in just under 6h 10m. Your travel time can differ by up to 2h 19m. 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 (92%), Japan Airlines (87%) and Cathay Pacific (87%).

  • 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 £169). Flying from Washington, D.C. Dulles Intl Airport to Seattle in June is currently the most expensive (average of £404). 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

Travelling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
Federal Way
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Why should you use Cheapflights to find cheap flight tickets from Dulles Intl to Seattle?

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Can Cheapflights find flights from Dulles Intl to Seattle with no change fees?

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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