Washington Dulles to Seattle-Tacoma
2300 miles great-circle distance, typically flown in 5h 02m with 5 airlines operating direct service from Washington Dulles (IAD) to Seattle-Tacoma (SEA). Cheapest fares are usually in January (around $249 return), with peak prices in August (around $747). Departures on a Tuesday tend to undercut weekend prices on this corridor.
Flying from Washington Dulles
Washington Dulles International is United Airlines' Mid-Atlantic hub and the larger of the two Washington-region airports. Metro's Silver Line extension opened in 2022, running from the airport's underground station directly to downtown Washington DC in around 50 minutes for $7. International long-haul through IAD is the deepest of any DC-area airport, with United, BA, Virgin Atlantic, Lufthansa, Air France, Qatar, Emirates and Ethiopian all running daily flights to global hubs.
Arriving in Seattle
Seattle-Tacoma is 14 miles south of downtown Seattle, with the Link Light Rail Red Line running directly from the airport station to Westlake in 38 minutes for $3.25 — possibly the simplest big-city airport transfer in the United States. Fares peak in mid-summer (June–August) and around Bumbershoot/Labor Day; January and February are the cheapest months despite winter rain.
Who flies IAD to SEA?
| Airline | IATA | Flight time | Cabin |
| United Airlines | UA | 5h 02m | Economy |
| Frontier Airlines | F9 | 5h 02m | Economy |
| American Airlines | AA | 5h 02m | Economy |
| Delta Air Lines | DL | 5h 02m | Economy |
| JetBlue Airways | B6 | 5h 02m | Economy |
5 carriers fly direct on this corridor. Frequencies vary by season — summer and winter holiday peaks see additional flights.
Best time to fly IAD→SEA
Synthesised from 12-month price aggregates. Cheapest months in green, peak in red.
Estimated baseline. Prices update on a 30-day cadence as Travelpayouts data refreshes. Cheapest day-of-week typically Tuesday.
Washington to Seattle FAQs
Direct flights from Washington Dulles (IAD) to Seattle-Tacoma (SEA) take approximately 5h 02m for the 2300-mile journey, plus 30–60 minutes of taxi, climb and descent. Total airport-to-airport time depends on cruise winds and air-traffic queueing on approach.
January is typically the cheapest month on this route, with one-way fares from $249. August is the peak — expect prices 2–3× higher. Book 4–8 weeks ahead for best fares; last-minute prices on this corridor rise sharply inside two weeks of departure.
5 carriers operate direct service from Washington Dulles (IAD) to Seattle-Tacoma (SEA): United Airlines, Frontier Airlines, American Airlines, Delta Air Lines and JetBlue Airways. Frequencies vary by season and carrier — United Airlines typically operates the highest weekly count on this corridor.
No — United States is domestic travel for US citizens. A US passport is not required for the 50 states, DC or US territories (Puerto Rico, US Virgin Islands, Guam, American Samoa, Northern Mariana Islands), though Real ID-compliant ID is required at TSA from May 2025.
Seattle-Tacoma (SEA) is the primary international airport for Seattle. Allow 30–60 minutes for the ground transfer by train, express bus, taxi or rideshare depending on traffic and time of day. See the airport's official website for current train and shuttle timetables.