Washington, D.C. (IAD) to Seattle (SEA) is about 2,300 miles and typically takes 5 h 10 min by air. Airlines with hubs at both ends are the likeliest to offer nonstops; otherwise expect a connection. Call (800) 490-3234 for live fares.
IAD to SEA at a glance
| Route | Washington, D.C. (IAD) to Seattle (SEA) |
|---|---|
| Distance | about 2,300 miles / 3,700 km |
| Typical flight time | 5 h 10 min (estimate) |
| Time difference | 3 hours behind |
| Route type | Domestic (U.S.) |
| Airlines with hubs here | Delta Air Lines, United Airlines, and Alaska Airlines |
About the Washington, D.C. to Seattle route
Covering around 2,300 miles, the trip from Washington, D.C. (IAD) to Seattle (SEA) is one of the longer domestic routes. Expect several hours in the air and a noticeable shift in local time.
Flight time and distance
A typical flight takes about 5 h 10 min gate to gate, with a realistic range of 4 h 50 min to 5 h 35 min depending on wind, routing and aircraft. That is an estimate based on the distance of roughly 2,300 miles (3,700 km), not a published schedule. Flights heading west usually take noticeably longer than flights heading east because of prevailing winds aloft, so the return flight can differ by 30 minutes or more.
Seattle is 3 hours behind Washington, D.C. on standard time, so the arrival time on your ticket will look different from the flight duration.
Among the 200 routes in our guides, IAD to SEA is longer than about 73% of them.
For comparison, Washington, D.C. to Los Angeles (IAD to LAX) is about 2,280 miles, so Seattle is about the same distance out from IAD.
The airports
Washington Dulles International Airport (IAD)
Dulles is United's main hub for the nation's capital and handles most long-haul international service for the region. Full IAD guide.
Seattle-Tacoma International Airport (SEA)
Sea-Tac is Alaska Airlines' home hub and a growing Delta gateway to Asia, which makes it a useful connecting point for Alaska, Hawaii and Pacific routes. Full SEA guide.
Other airports are worth a look: around Washington, D.C., Reagan National (DCA) and Baltimore/Washington (BWI); and around Seattle, Portland (PDX). Comparing them can change the price or the travel time to your final destination.
Airlines on this route
No single carrier we cover has hubs at both IAD and SEA. Delta Air Lines (at SEA), United Airlines (at IAD), and Alaska Airlines (at SEA) each operate a large network at one end, so many itineraries on this route connect rather than fly nonstop.
Nonstop availability on any route can shift from one season to the next, so treat this as a guide to who is likely to serve the market, not a timetable.
Common connection points
Connecting itineraries on this route often look like Alaska Airlines via San Francisco (SFO), which adds about 790 miles (34% beyond the direct distance). Choose the connection with the best weather odds for your travel month and leave a comfortable layover; our layover guide explains how much time is realistic.
Best time to fly
Timing matters here. At SEA, july through September has the clearest weather and the heaviest demand, including cruise-season traffic to Alaska. At IAD, international demand peaks in summer; weather disruptions are generally milder than in the Northeast.
Ground transport
Getting to and from IAD
Metro's Silver Line now runs to the airport, offering a rail option into Washington.
Getting to and from SEA
Link light rail runs from the terminal to downtown Seattle in roughly 40 minutes without road traffic.
Booking tips
Fares on routes with strong business demand rarely drop sharply at the last minute. Book once your dates are firm and review the 24-hour rule in case plans change.
Frequently asked questions
How long is the flight from Washington, D.C. to Seattle?
A typical IAD to SEA flight takes about 5 h 10 min, with a likely range of 4 h 50 min to 5 h 35 min. Actual time depends on wind, routing, aircraft and whether you connect.
How far is Seattle from Washington, D.C. by air?
The great-circle distance between IAD and SEA is about 2,300 miles (3,700 km).
Which airlines fly from Washington, D.C. to Seattle?
Delta Air Lines, United Airlines, and Alaska Airlines have a major presence at IAD or SEA, and service varies by season. Ask us to check current nonstop and connecting options.
What is the time difference between Washington, D.C. and Seattle?
Seattle is 3 hours behind Washington, D.C. on standard time. Daylight saving time can change the gap for part of the year.
Are there other airports near Washington, D.C.?
Yes. Nearby alternatives include Reagan National (DCA) and Baltimore/Washington (BWI). Comparing them can change both fare and travel time.
When is the best time to book IAD to SEA?
Domestic fares are often competitive one to three months ahead, while international trips benefit from more lead time. Compare several dates, since fares are priced flight by flight.
Explore related routes
More flights involving Washington, D.C. (IAD)
- Washington, D.C. to DenverIAD to DEN
- Washington, D.C. to Los AngelesIAD to LAX
- Washington, D.C. to San FranciscoIAD to SFO
More flights involving Seattle (SEA)
- Atlanta to SeattleATL to SEA
- Austin to SeattleAUS to SEA
- Boston to SeattleBOS to SEA
- Detroit to SeattleDTW to SEA
- Dubai to SeattleDXB to SEA
- Houston to SeattleIAH to SEA
Last reviewed October 22, 2026. FlighTicketHub provides general information; confirm details with the airline before you travel.