IAD to SEA from $255 in economy

UAUnited Airlines

Round Trip•Economy

IAD

Washington Dulles International Airport

Washington, United States

SEA

Seattle–Tacoma International Airport

Seattle / Tacoma, United States

$449 USD

-43%$255 USD

Verified 14 days ago

September 2026

Today

Mon

Tue

Wed

Thu

Fri

Sat

Sun

31$255 1$261 2$265 3$373 4$335 5$255 6$255 7$255 8$265 9$265 10$294 11$255 12$255 13$265 14$255 15$265 16$265 17$265 18$295 19$255 20$255 21$255 22$255 23$255 24$265 25$255 26$306 27$306 28$306 29$306 30$306 1$357 2$357 3$357 4$357

Limited Availability

11% of dates checked are available within 10% of the lowest price

Friday, September 18th, 2026

8 round-trip options

Returning

Wed, Sep 23, 2026•5 Day Trip

$295 USD

Google Flights

Returning

Thu, Sep 24, 2026•6 Day Trip

$295 USD

Google Flights

Returning

Sat, Sep 26, 2026•8 Day Trip

$305 USD

Google Flights

Returning

Sun, Sep 27, 2026•9 Day Trip

$305 USD

Google Flights

Returning

Mon, Sep 28, 2026•10 Day Trip

$295 USD

Google Flights

Returning

Tue, Sep 29, 2026•11 Day Trip

$295 USD

Google Flights

Returning

Thu, Oct 1, 2026•13 Day Trip

$346 USD

Google Flights

Returning

Fri, Oct 2, 2026•14 Day Trip

$346 USD

Google Flights

Washington (IAD) to Seattle / Tacoma (SEA) flight deal in economy from $255

Washington Dulles International Airport

Seattle–Tacoma International Airport

September 2026

Friday, September 18th, 2026