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Cheap flights from Washington, D.C. Dulles Intl Airport to Seattle from £110

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 13/8. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — SEA
23 Jul — 30 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 18 July 2025.

Round-trip from

£195

One-way from

£110

Popular in

December

Cheapest in

February

Average price

£341
Hawaiian Airlines
  • Hawaiian Airlines
  • 13/8-20/8
  • Nonstop
  • 10h 47m total
  • Washington, D.C. to Seattle
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Alaska Airlines
  • Alaska Airlines
  • 13/8
  • 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 (£6 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease (£6 potential savings vs. average return price).
Search Deals
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 18 July 2025.

Wed 13/806:30IAD - SEA
Nonstop5h 47mHawaiian Airlines
Wed 20/816:20SEA - IAD
Nonstop5h 00mHawaiian Airlines
Deal found 16/7£195
Tue 12/818:13IAD - SEA
Nonstop5h 47mAlaska Airlines
Wed 20/816:20SEA - IAD
Nonstop5h 00mAlaska Airlines
Deal found 16/7£204
Tue 9/907:35IAD - SEA
Nonstop5h 45mDelta
Tue 23/921:55SEA - IAD
Nonstop5h 06mDelta
Deal found 18/7£207
Wed 13/822:06IAD - SEA
Nonstop5h 50mUnited Airlines
Wed 20/823:58SEA - IAD
1 stop8h 30mUnited Airlines
Deal found 18/7£214
Wed 17/905:45IAD - SEA
2 stops14h 10mSouthwest
Wed 24/905:15SEA - IAD
1 stop8h 00mSouthwest
Deal found 17/7£225
Sun 9/1112:50IAD - SEA
1 stop7h 25mSun Country Air
Thu 13/1118:25SEA - IAD
1 stop13h 34mSun Country Air
Deal found 18/7£228

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 18 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

Wed 13/8

06:30-09:17

Nonstop5h 47m

Seattle/Tacoma Intl

Wed 20/8

16:20-00:20

Nonstop5h 00m

£195

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 12/8

18:13-21:00

Nonstop5h 47m

Seattle/Tacoma Intl

Wed 20/8

16:20-00:20

Nonstop5h 00m

£204

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Tue 9/9

07:35-10:20

Nonstop5h 45m

Seattle/Tacoma Intl

Sat 20/9

21:55-06:01

Nonstop5h 06m

£207

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 13/8

22:06-00:56

Nonstop5h 50m

Seattle/Tacoma Intl

Wed 20/8

23:58-11:28

1 stop8h 30m

£214

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 17/9

05:45-16:55

2 stops14h 10m

Seattle/Tacoma Intl

Wed 24/9

05:15-16:15

1 stop8h 00m

£225

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Sun 9/11

12:50-17:15

1 stop7h 25m

Seattle/Tacoma Intl

Thu 13/11

18:25-10:59

1 stop13h 34m

£228

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 13/8

17:25-23:51

1 stop9h 26m

£110

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Mon 18/8

17:55-20:48

Nonstop5h 53m

£111

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Fri 3/10

18:30-17:01

1 stop25h 31m

£114

Washington, D.C.Seattle

IAD - SEA

IADSEA

Washington, D.C. Dulles Intl

Wed 8/10

17:42-09:20

1 stop18h 38m

£115

Flights are sorted by cheapest return flights first.

Deals found on 18/7

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 11 July 2025.

The best time to book flights from Washington, D.C. Dulles Intl Airport to Seattle is 58 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 18 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 18 July 2025.

The most flights from IAD to SEA are scheduled on a Thursday (32 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (12 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 18 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

Overall

8.0

Comfort

7.8

Boarding

8.1

Food

7.1

Crew

8.5

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Alaska Airlines
8.0
Very Good
10,000 reviews
Alaska Airlines
8.0
Very Good
10,000 reviews
Check prices

Overall

8.0

Comfort

7.8

Boarding

8.1

Food

7.1

Crew

8.5

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Southwest
8.0
Very Good
4,238 reviews
Alaska Airlines
8.0
Very Good
10,000 reviews
Check prices

Overall

8.0

Comfort

7.8

Boarding

8.1

Food

7.1

Crew

8.5

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Delta
8.0
Very Good
7,958 reviews
Alaska Airlines
8.0
Very Good
10,000 reviews
Check prices

Overall

8.0

Comfort

7.8

Boarding

8.1

Food

7.1

Crew

8.5

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Hawaiian Airlines
7.8
Good
2,583 reviews
Alaska Airlines
8.0
Very Good
10,000 reviews
Check prices

Overall

8.0

Comfort

7.8

Boarding

8.1

Food

7.1

Crew

8.5

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
United Airlines
7.4
Good
8,865 reviews
Alaska Airlines
8.0
Very Good
10,000 reviews
Check prices

Overall

8.0

Comfort

7.8

Boarding

8.1

Food

7.1

Crew

8.5

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.

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 22 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 £195 on this airline. Additional options worth looking into are Alaska Airlines and Delta, starting at £204 and £207 round-trip. Hawaiian Airlines is 36% 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 Alaska Airlines, with whom users have recently found tickets for as low as £110. However, be on the lookout for offers from United Airlines and Sun Country Air, 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%), China Eastern (82%) and Delta (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 Seattle?

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Tacoma
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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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