$148 Cheap Flights from Washington (IAD) to Seattle (SEA)

View $148 flight on Wed, Aug 13, 2025Opens in a new window

Popular airlines from Washington Dulles Intl. Airport (IAD) to Seattle-Tacoma International Airport (SEA)

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Cheap Flights from Washington to Seattle (IAD-SEA)

Prices were available within the past 7 days and start at $148 for one-way flights and $274 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Bargain Flight
Wed, Oct 29 - Tue, Nov 4
IAD
Washington
SEA
Seattle
$274 Roundtrip, found 1 day ago
$274
Roundtrip
found 1 day ago
Select Bargain Flight flight, departing Wed, Oct 29 from Washington to Seattle, returning Tue, Nov 4, priced at $274 found 1 day ago
American Airlines
Wed, Oct 22 - Tue, Nov 4
IAD
Washington
SEA
Seattle
$277 Roundtrip, found 12 hours ago
$277
Roundtrip
found 12 hours ago
Select American Airlines flight, departing Wed, Oct 22 from Washington to Seattle, returning Tue, Nov 4, priced at $277 found 12 hours ago
Hawaiian Airlines
Wed, Aug 27 - Sat, Sep 13
IAD
Washington
SEA
Seattle
$277 Roundtrip, found 4 days ago
$277
Roundtrip
found 4 days ago
Select Hawaiian Airlines flight, departing Wed, Aug 27 from Washington to Seattle, returning Sat, Sep 13, priced at $277 found 4 days ago
United
Tue, Sep 2 - Sat, Sep 6
IAD
Washington
SEA
Seattle
$277 Roundtrip, found 1 hour ago
$277
Roundtrip
found 1 hour ago
Select United flight, departing Tue, Sep 2 from Washington to Seattle, returning Sat, Sep 6, priced at $277 found 1 hour ago
Delta
Tue, Sep 2 - Sat, Sep 6
IAD
Washington
SEA
Seattle
$277 Roundtrip, found 1 hour ago
$277
Roundtrip
found 1 hour ago
Select Delta flight, departing Tue, Sep 2 from Washington to Seattle, returning Sat, Sep 6, priced at $277 found 1 hour ago
Bargain Flight
Mon, Aug 18 - Tue, Sep 2
IAD
Washington
SEA
Seattle
$283 Roundtrip, found 3 hours ago
$283
Roundtrip
found 3 hours ago
Select Bargain Flight flight, departing Mon, Aug 18 from Washington to Seattle, returning Tue, Sep 2, priced at $283 found 3 hours ago
Alaska Airlines
Thu, Aug 14 - Wed, Aug 20
IAD
Washington
SEA
Seattle
$287 Roundtrip, found 2 hours ago
$287
Roundtrip
found 2 hours ago
Select Alaska Airlines flight, departing Thu, Aug 14 from Washington to Seattle, returning Wed, Aug 20, priced at $287 found 2 hours ago
Alaska Airlines
Wed, Oct 22 - Tue, Nov 4
IAD
Washington
SEA
Seattle
$289 Roundtrip, found 12 hours ago
$289
Roundtrip
found 12 hours ago
Select Alaska Airlines flight, departing Wed, Oct 22 from Washington to Seattle, returning Tue, Nov 4, priced at $289 found 12 hours ago
Bargain Flight
Thu, Aug 28 - Tue, Sep 2
IAD
Washington
SEA
Seattle
$293 Roundtrip, just found
$293
Roundtrip
just found
Select Bargain Flight flight, departing Thu, Aug 28 from Washington to Seattle, returning Tue, Sep 2, priced at $293 just found
United
Tue, Aug 19 - Wed, Aug 27
IAD
Washington
SEA
Seattle
$294 Roundtrip, found 9 hours ago
$294
Roundtrip
found 9 hours ago
Select United flight, departing Tue, Aug 19 from Washington to Seattle, returning Wed, Aug 27, priced at $294 found 9 hours ago

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

September is typically the cheapest month to fly

From $183 - $296 per traveler.

Graph displaying average flight prices per month

Alternative airports near Seattle

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Seattle - Tacoma Intl. SEA. Cheapest option available. Average driving time to city center is 20 minutes. Flights from $627
SEA
Seattle - Tacoma Intl.
Cheapest
Average driving time to city center20 min
Flights from $627
Flights from Washington (IAD) to Seattle (SEA)
Origin airport
Washington Dulles Intl.
Destination airport
Seattle - Tacoma Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Southwest Airlines, Sun Country Airlines, United
Roundtrip price
$273
Distance
2299 mi
Average flight time
2 hours 48 mins

Frequently asked questions

How much does a flight from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA) cost?
You can score cheap return tickets from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA) starting from $271. Book a seat and take off on your trip. This information is based on the cheapest price found on Expedia for this return journey departing within the next three months. This airfare is for a Alaska Airlines flight leaving IAD on August 12 2025 and touching down at SEA. The price was last updated on July 17 2025 and has not changed since.
What is the cheapest month to fly from IAD to SEA?
The cheapest flights from IAD to SEA are usually during off-peak season, when demand is lower. To save money, avoid flying during public holidays, school breaks and major local events.
Which airlines fly direct from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
Fly straight to Seattle - Tacoma Intl. Airport (SEA). 3 airlines offer direct flights from Washington Dulles Intl. Airport (IAD), including:

  • Delta Air Lines
  • United Airlines
  • Alaska Airlines

What is the cheapest airline that flies from IAD to SEA?
Currently, the cheapest carrier operating one-way flights from IAD to SEA is United. You can book a seat on this route from $149. This fare is based on the lowest price found on Expedia departing within the next three months. The flight takes off from IAD on August 19 2025. Prices were last updated on July 17 2025 and have not changed since.
How many flights per day from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
When departing from Washington Dulles Intl. Airport (IAD), you can pick from an average of 3 daily nonstop flights to Seattle - Tacoma Intl. Airport (SEA).
What are the most popular departure times for flights from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
More travelers fly between IAD and SEA at 4 PM than at any other point in the day. Rather go when it's quieter? Consider flying outside peak hours and you're likely to save on your fare as well.
What day of the week has the most flights from IAD to SEA?
Friday offers the most flights from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA). Consider leaving on this day and you'll have the best chance of finding a departure that fits your itinerary.
What is the earliest flight from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
The first flight of the day out of Washington Dulles Intl. Airport (IAD) is at around 4:05PM UTC-5. Board this plane and you'll reach Seattle - Tacoma Intl. Airport (SEA) at approximately 7:06PM UTC-8. The total time in the air is 6h 1m.
How long does it take to fly from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
It usually takes 6 hours and 1 minute to travel the 2,300 mi from IAD to SEA.
What airline has the least delays from IAD to SEA?
With 84% of flights generally landing on time, United Airlines has the best on-time performance for direct flights from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA). To check your flight status and receive notifications if anything changes, head to the Expedia App.
What is the best time to fly from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
To avoid potential delays on the Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA) route, aim to travel before 3 PM. Flights after this time are 22% more likely to be canceled.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports do you fly into for Seattle from Washington Dulles Intl. Airport (IAD)?
Seattle - Tacoma Intl. Airport (SEA) is the only airport in Seattle with direct flights from Washington Dulles Intl. Airport (IAD). Consider the options and find affordable fares on Expedia.
Is it cheaper to buy a plane ticket from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA) last-minute?
Holding off until right before your break to book your flight from IAD to SEA generally means paying more. While it's possible to find some last-minute discounts, they're not always guaranteed. Keep your travel schedule open for the best chance of landing a bargain.
Is it cheaper to book an IAD to SEA flight and hotel package?
Booking an IAD to SEA flight and hotel package tends to be cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels in one place. Pick from our extensive range of accommodations and then add car rentals, activities and flights to your booking. Bundle it all together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Washington Dulles Intl. Airport (IAD) to Seattle - Tacoma Intl. Airport (SEA)?
In most instances, you can cancel or reschedule your IAD to SEA flight. However, additional charges may apply, especially if your booking was made over 24 hours ago. Double-check your itinerary for the airline's guidelines and fees on flight changes, or if you need further details, visit our Customer Service portal.

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