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Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from £108

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 16/8. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — SEA
11 Jul — 18 Jul1
1 adult

Cheap flight deals from Dulles Intl to Seattle

Discover tips and strategies to find the most affordable flight options for your journey from Dulles Intl (IAD) to Seattle (SEA). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated 6 July 2025.

Round-trip from

£198

One-way from

£108

Popular in

December

Cheapest in

February

Average price

£335
Hawaiian Airlines
  • Hawaiian Airlines
  • 19/8-26/8
  • Nonstop
  • 10h 49m total
  • Washington, D.C. to Seattle
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Hawaiian Airlines
  • Hawaiian Airlines
  • 16/8
  • 1 total stop
  • 11h 44m total
  • Washington, D.C. to Seattle
Search Deals
Highest demand for flights based on searches. 2% potential increase in price (£5 potential increase over avg. return price).
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Cheapest flight prices on average. 2% potential price decrease (£6 potential savings vs. average return price).
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Average for round-trip flights in July 2025
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Find flight deals from Dulles Intl to Seattle

Cheapest flights from Dulles Intl to Seattle
Explore the most affordable flight options available from Dulles Intl to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 6 July 2025.

Tue 19/809:00IAD - SEA
Nonstop5h 47mHawaiian Airlines
Tue 26/823:30SEA - IAD
Nonstop5h 02mHawaiian Airlines
Deal found 5/7£198
Sat 8/1117:55IAD - SEA
Nonstop5h 59mUnited Airlines
Tue 11/1109:25SEA - IAD
1 stop8h 41mUnited Airlines
Deal found 5/7£207
Wed 13/807:35IAD - SEA
Nonstop5h 45mDelta
Mon 18/821:55SEA - IAD
Nonstop5h 00mDelta
Deal found 4/7£210
Wed 13/808:10IAD - SEA
1 stop11h 44mAlaska Airlines
Wed 13/819:05SEA - IAD
1 stop8h 45mAlaska Airlines
Deal found 5/7£213
Thu 21/812:48IAD - SEA
1 stop12h 55mSun Country Air
Thu 28/823:55SEA - IAD
1 stop9h 38mSun Country Air
Deal found 5/7£216
Sat 23/815:50IAD - SEA
1 stop9h 40mSouthwest
Wed 27/806:45SEA - IAD
2 stops12h 20mSouthwest
Deal found 4/7£221

Cheapflights Fare Finder

Customise your flight search to find flights from Dulles Intl to Seattle that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 858,174 searches. Data last updated 6 July 2025.
Use the filters below to find and compare flights from Washington, D.C. Dulles Intl Airport to Seattle that are best for you.

Fly from

Dulles Intl

Fly to

Seattle

Route

Depart

Return

Price

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 19/8

09:00-11:47

Nonstop5h 47m

Seattle/Tacoma Intl

Tue 26/8

23:30-07:32

Nonstop5h 02m

£198

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 8/11

17:55-20:54

Nonstop5h 59m

Seattle/Tacoma Intl

Tue 11/11

09:25-21:06

1 stop8h 41m

£207

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 13/8

07:35-10:20

Nonstop5h 45m

Seattle/Tacoma Intl

Mon 18/8

21:55-05:55

Nonstop5h 00m

£210

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 13/8

08:10-16:54

1 stop11h 44m

Seattle/Tacoma Intl

Wed 13/8

19:05-06:50

1 stop8h 45m

£213

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Thu 21/8

12:48-22:43

1 stop12h 55m

Seattle/Tacoma Intl

Thu 28/8

23:55-12:33

1 stop9h 38m

£216

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 23/8

15:50-22:30

1 stop9h 40m

Seattle/Tacoma Intl

Wed 27/8

06:45-22:05

2 stops12h 20m

£221

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sat 16/8

08:10-16:54

1 stop11h 44m

£108

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Mon 11/8

07:35-10:20

Nonstop5h 45m

£109

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 14/11

13:50-00:05

2 stops13h 15m

£111

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 3/10

18:30-17:01

1 stop25h 31m

£112

Flights are sorted by cheapest return flights first.

Deals found on 4/7

Showing 1-10 of 13 results
1
2

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
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

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?

Use this chart to determine the optimal time to book a return flight from Dulles Intl to Seattle. Price data was last updated on 27 June 2025.

The best time to book flights from Washington, D.C. Dulles Intl Airport to Seattle is 66 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 £622). Flying from Washington, D.C. Dulles Intl Airport to Seattle in July is currently the most expensive (average of £946). 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?

Find hourly flight availability from Dulles Intl to Seattle. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 6 July 2025.

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.

Weekly flight availability from Washington, D.C. Dulles Intl Airport to Seattle

Explore weekly flight availability from Dulles Intl to Seattle. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated 6 July 2025.

The most flights from IAD to SEA are scheduled on a Sunday (31 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (21 on average).

Reviews of airlines servicing Seattle

Get insights into the airlines that provide service to Seattle. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Seattle. Reviews last updated 6 July 2025.
Read reviews from past customers who have flown with Alaska Airlines, Southwest, andDelta from Washington, D.C. Dulles Intl Airport to Seattle. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very Good
10,000 reviews
Check prices

Comfort

7.8

Crew

8.5

Overall

8.0

Boarding

8.1

Entertainment

7.1

Food

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Alaska Airlines
8.0
Very Good
10,000 reviews
Alaska Airlines
8.0
Very Good
10,000 reviews
Check prices

Comfort

7.8

Crew

8.5

Overall

8.0

Boarding

8.1

Entertainment

7.1

Food

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Southwest
8.0
Very Good
4,259 reviews
Alaska Airlines
8.0
Very Good
10,000 reviews
Check prices

Comfort

7.8

Crew

8.5

Overall

8.0

Boarding

8.1

Entertainment

7.1

Food

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Delta
8.0
Very Good
7,967 reviews
Alaska Airlines
8.0
Very Good
10,000 reviews
Check prices

Comfort

7.8

Crew

8.5

Overall

8.0

Boarding

8.1

Entertainment

7.1

Food

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Hawaiian Airlines
7.8
Good
2,546 reviews
Alaska Airlines
8.0
Very Good
10,000 reviews
Check prices

Comfort

7.8

Crew

8.5

Overall

8.0

Boarding

8.1

Entertainment

7.1

Food

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
United Airlines
7.4
Good
8,849 reviews
Alaska Airlines
8.0
Very Good
10,000 reviews
Check prices

Comfort

7.8

Crew

8.5

Overall

8.0

Boarding

8.1

Entertainment

7.1

Food

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

Related info for your journey

Find useful and relevant information for your journey from Dulles Intl to Seattle. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • 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 24 daily inbound flights from Washington, D.C. Dulles Intl from 0 different airlines.

  • What are the cheapest airlines flying from Washington, D.C. Dulles Intl Airport to Seattle round-trip?

    Our cheapest airline available from Washington, D.C. Dulles Intl Airport to Seattle is Hawaiian Airlines. Our recent data shows that you can find tickets from as low as £198 on this airline. Additional options worth looking into are United Airlines and Delta, starting at £207 and £210 round-trip. Hawaiian Airlines is 34% cheaper than the average price of flights available within the next 90 days to this destination.

  • What are the cheapest airlines to fly from Washington, D.C. Dulles Intl Airport to Seattle one-way?

    The cheapest airline one-way is Hawaiian Airlines, with whom users have recently found tickets for as low as £108. However, be on the lookout for offers from Delta and Southwest, as they are both options that can get you from Washington, D.C. Dulles Intl Airport to Seattle for a low price.

  • 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 Japan Airlines (97%), Ethiopian Air (83%) and China Eastern (82%).

  • 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 £622). Flying from Washington, D.C. Dulles Intl Airport to Seattle in July is currently the most expensive (average of £946). 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 Washington, D.C. Dulles Intl Airport?

Book flights to Washington, D.C. Dulles Intl Airport if you plan to visit one of these locations
Tacoma
Leavenworth
Bothell
SeaTac

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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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