$149 Cheap United flights Seattle (SEA) to Washington (IAD)

View $149 flight on Thu, Jul 31, 2025Opens in a new window

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$149 Cheap United flights Seattle (SEA) to Washington (IAD)

Prices were available within the past 7 days and start at $149 for one-way flights and $277 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

United
Wed, Sep 17 - Sat, Sep 20
SEA
Seattle
IAD
Washington
$277 Roundtrip, found 1 hour ago
$277
Roundtrip
found 1 hour ago
Select United flight, departing Wed, Sep 17 from Seattle to Washington, returning Sat, Sep 20, priced at $277 found 1 hour ago
United
Tue, Oct 28 - Tue, Nov 4
SEA
Seattle
IAD
Washington
$283 Roundtrip, found 12 hours ago
$283
Roundtrip
found 12 hours ago
Select United flight, departing Tue, Oct 28 from Seattle to Washington, returning Tue, Nov 4, priced at $283 found 12 hours ago
United
Wed, Aug 27 - Sat, Aug 30
SEA
Seattle
IAD
Washington
$291 Roundtrip, found 1 hour ago
$291
Roundtrip
found 1 hour ago
Select United flight, departing Wed, Aug 27 from Seattle to Washington, returning Sat, Aug 30, priced at $291 found 1 hour ago
United
Tue, Oct 28 - Tue, Nov 4
SEA
Seattle
IAD
Washington
$292 Roundtrip, found 12 hours ago
$292
Roundtrip
found 12 hours ago
Select United flight, departing Tue, Oct 28 from Seattle to Washington, returning Tue, Nov 4, priced at $292 found 12 hours ago
United
Thu, Aug 14 - Sat, Aug 16
SEA
Seattle
IAD
Washington
$299 Roundtrip, found 3 hours ago
$299
Roundtrip
found 3 hours ago
Select United flight, departing Thu, Aug 14 from Seattle to Washington, returning Sat, Aug 16, priced at $299 found 3 hours ago
United
Wed, Aug 13 - Sat, Aug 16
SEA
Seattle
IAD
Washington
$301 Roundtrip, found 1 hour ago
$301
Roundtrip
found 1 hour ago
Select United flight, departing Wed, Aug 13 from Seattle to Washington, returning Sat, Aug 16, priced at $301 found 1 hour ago
Flights from Seattle Paine Field Intl. Airport (PAE) to Washington (IAD)
Origin airport
Seattle Paine Field Intl. Airport
Destination airport
Washington Dulles Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Hawaiian Airlines, Southwest Airlines, Sun Country Airlines, United
Popular airline
Alaska Airlines
Distance
2297 mi
Average flight time
8 hours 40 mins

Frequently asked questions

How much is a United Airlines flight from Seattle - Tacoma Intl. Airport (SEA) to Washington Dulles Intl. Airport (IAD)?
Finding cheap one-way United Airlines flights from SEA to IAD from $149 on Expedia couldn't be easier --- just filter by "Price (lowest to highest)." Or check out our budget-friendly round-trip fares from $277 for your next break.**These prices were available on Expedia within the past 7 days, for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.
What is the cheapest month to fly from SEA to IAD with United Airlines?
January is one of the cheapest months to jet off to Washington with United Airlines. You could also find excellent prices on one-way and round-trip tickets in February.
What is the cheapest time to book flights from Seattle - Tacoma Intl. Airport (SEA) to Washington Dulles Intl. Airport (IAD) with United Airlines?
Start searching one to three months ahead of your travel date to find cheaper fares on United Airlines flights from Seattle - Tacoma Intl. Airport (SEA) to Washington Dulles Intl. Airport (IAD). You can save 25% by booking your domestic flight 34 to 86 days in advance compared to last-minute reservations made 6 to 12 days out. You could also cut costs by buying your fare on a Sunday, as it's 6% cheaper on average than a Monday, the most expensive day to book.* Time it well, and you can enjoy significant savings on domestic flights.*Ideal booking window recommendation is based on average round-trip ticket prices for January through November for 2024. Best day of the week to book recommendation is based on average round-trip ticket prices for January through October 2024. All data sourced from ARC's global airline sales database.
Does United Airlines fly nonstop from Seattle - Tacoma Intl. Airport (SEA) to Washington Dulles Intl. Airport (IAD)?
United Airlines has direct flights from Seattle - Tacoma Intl. Airport (SEA) to Washington Dulles Intl. Airport (IAD), with 7 departures each week. Simply use the "Nonstop" and "Airline" filters during your search on Expedia to see all direct United Airlines flights to IAD.
How long does it take to fly from SEA to IAD with United Airlines?
It takes around 5h 6m to travel nonstop from Seattle - Tacoma Intl. Airport (SEA) to Washington Dulles Intl. Airport (IAD) with United Airlines.
What is the earliest United Airlines flight from SEA to IAD?
Setting off from SEA at 8:00AM UTC-8, the first United Airlines flight to IAD lands at 4:06PM UTC-5. Flying earlier in the day means you'll be less likely to encounter cancellations or delays.* Prefer to travel later? The last United Airlines flight from SEA to IAD departs at 8:00AM UTC-8 and touches down at 4:06PM UTC-5.*Most reliable time of the day recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports does United Airlines fly into in Washington?
United Airlines flights from Seattle - Tacoma Intl. Airport (SEA) to Washington come in to Washington Dulles Intl. Airport (IAD), Ronald Reagan Washington National Airport (DCA) and Baltimore Washington Intl. Thurgood Marshall Airport (BWI). The primary Washington gateway served by this airline is IAD. It's always worth exploring flights arriving at other nearby airports on Expedia as they may offer cheaper prices.
Why fly with United Airlines from SEA to IAD?
Offering a rewarding loyalty program, United Airlines is a top pick for many passengers departing from SEA to IAD. Plus, as a United Mileage Plus and One Key™ member booking through Expedia, you could earn OneKeyCash™* on eligible flights along with your airline miles.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.
What type of plane does United Airlines fly from Seattle - Tacoma Intl. Airport (SEA) to Washington Dulles Intl. Airport (IAD)?
You'll likely board a Boeing 737-900 or a Boeing 737-800 when flying United Airlines from Seattle - Tacoma Intl. Airport (SEA) to Washington Dulles Intl. Airport (IAD). However, keep in mind that a different plane could be assigned to your route depending on operational factors.
Can I change or cancel my United Airlines flight from Seattle - Tacoma Intl. Airport (SEA) to Washington Dulles Intl. Airport (IAD)?
Changes are generally free within 24 hours of booking, but your airline may charge you after that time. For further details about altering your reservation, go to your "Trips," select your flight and click on "Manage Booking." If you'd like the freedom to change your plans without additional charges, check the "Changes included" and "No cancel fee" filters when organizing your next break.

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