Flights Washington → Seattle — September 21, 2026

One way · Economy · 1 adult · price per person

The cheapest flight observed for Monday, September 21, 2026 on the Washington–Seattle route: Alaska Airlines AS737, from Washington Dulles (IAD) to Seattle-Tacoma (SEA), departs 5:57 PM, arrives 8:44 PM, direct, 5h 47m, $221 per person. Fare as listed by Aviasales: carry-on bag not included (personal item only), checked bag not included, changes allowed for a fee, non-refundable. Price found in an Aviasales search on September 10, 2026 and read by AirSource on September 10, 2026, 20:47 UTC: it is not guaranteed and is confirmed on Aviasales at booking time.

Lowest price observed in the available data

Alaska Airlines AS737

Direct · Washington Dulles (IAD) → Seattle-Tacoma (SEA)

Direct

5:57 PM

Mon, Sep 21

Washington Dulles (IAD)

5h 47m

direct

8:44 PM

Mon, Sep 21

Seattle-Tacoma (SEA)

Airline: Alaska Airlines (AS)
Flight: AS737
Departure: Washington Dulles (IAD) · September 21, 2026 · 5:57 PM local time (UTC-4)
Arrival: Seattle-Tacoma (SEA) · September 21, 2026 · 8:44 PM local time (UTC-7)
Stops: Direct (no plane change, as stated by the source; it can include a stop)
Duration: 5h 47m
Carry-on bag: not included (personal item only)
Checked bag: not included
Changes: allowed for a fee
Refund: non-refundable
Last observed price: $221 per person, one way
Observed: Price and fare conditions found in an Aviasales search on September 10, 2026 · read by AirSource on September 10, 2026, 20:47 UTC

Looking for other times? All Washington–Seattle flights on September 21, 2026 on Aviasales.

Lowest price observed in the available data

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