Route guide · 2,300 miles
Cheap Flights from Washington to Seattle
IAD → SEA · Nonstop 5h 10m · Live round-trip fares
The run from Washington (IAD) to Seattle (SEA) is 2,300 miles of sky, and ticket prices on it are anything but steady. One week can cost double the next. Booking about 4–8 weeks in advance — and watching fares with a free Airfare Deal alert — is how regulars on this route keep costs down.
Live fares for IAD → SEA are updating. Use the search below for real-time prices.
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See live fares
Updated daily
Flight time
5h 10m
Nonstop, typical
Distance
2,300 mi
IAD → SEA
Book ahead
4–8 weeks
Best window, typically
Nonstop airlines
1
United Airlines
Nonstop flights from Washington to Seattle
The fastest way between the two cities is the nonstop: about 5h 10m for the 2,300-mile run from IAD to SEA. Those flights are flown by United Airlines. Prices behave best when you book 4–8 weeks out.
Booking insights: Washington → Seattle
- Distance: 2,300 miles · nonstop flight time: 5h 10m.
- Cheapest upcoming week in the live data starts around Nov 26, with fares from $215.
- Fares tend to bottom out when you book about 4–8 weeks ahead — earlier than that rarely helps, later usually hurts.
- Midweek departures (Tue–Thu) are consistently cheaper than weekend flights.
- A free fare alert beats daily checking: we watch this route and ping you when prices drop.
Price trend
Cheapest departure weeks ahead
Departing around Nov 26 is currently the cheapest window — about $61 less than the nearest weeks. Based on recent fares found for this route; prices change quickly.
Cheapest month · Washington → Seattle
November 2026
Every date's recent round-trip fare, at a glance.
Fares from
$215
Cheapest: Thu, Nov 26 — $215
Get this fare →Recent fares found for specific dates in November 2026. Blank days had no recent fare in our data — ask our team and we'll check them for you.
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Flying from Washington to Seattle: what you need to know
The flight
This is one of the long ones: 2,300 miles from IAD to SEA, about 5h 10m on a nonstop. Treat it like a short international flight — real meal plan, charged devices, a layer for the cabin — and the hours go much easier.
Airlines on this route
United Airlines flies this route nonstop. That matters more than it sounds: the cheapest fare on one carrier is rarely the same product as the cheapest on another. Checked-bag fees, free seat selection and change rules all differ, so compare the full trip cost before you pick a winner. See our airline guides for exactly what each carrier charges — then send an enquiry and we'll confirm the all-in price for your dates.
Leaving from Washington (IAD)
Plan to be at the airport two hours before a domestic departure — ninety minutes can work at smaller airports outside peak times, but security lines are the one variable you can't control. If you're checking a bag, add time rather than cutting it close. Our Washington airport guide covers terminals, parking and ground transport so you can plan the trip to the airport, not just the flight.
Arriving in Seattle (SEA)
Before you land, know how you're getting from the airport to where you're staying — it's the part of the trip people forget to plan. The Seattle airport guide lays out your ground options, from transit and shuttles to rideshares and rental cars. Flying back the other way? Check Seattle to Washington fares — prices on the return direction often move on a different rhythm.
When to book
For a trip of 2,300 miles, booking 4–8 weeks ahead typically lands you in the sweet spot. Leave it to the final two weeks and prices usually climb as the cheapest seats sell out. If your dates are flexible, midweek departures are where the lower fares hide on most domestic routes.
Good to know before you go
- Screenshot your fare before you enquire — prices move, and a saved fare helps our team match or beat it.
- Flexible dates? Search a few days either side — one day can change the fare a lot.
- Morning flights are delayed less often than evening ones — earlier departures have the best on-time record.
- Basic economy fares often exclude checked bags and seat selection. Price the whole trip, not the headline fare.
- Get to the airport two hours before departure; security, not the flight, is the part that runs late.
Washington to Seattle flight FAQs
How long is the flight from IAD to SEA?
Plan on about 5h 10m in the air for a nonstop from Washington to Seattle — the route runs roughly 2,300 miles. Connecting flights typically add 2–4 hours.
Are there nonstop flights from Washington to Seattle?
United Airlines typically operate nonstop flights from IAD to SEA. Nonstops are usually cheapest when booked 4–8 weeks ahead of departure.
What is the cheapest month to fly from Washington to Seattle?
Travelers usually find the gentlest prices away from peak periods — think post-holiday January and the early-fall weeks. Midweek dates inside those windows are cheaper still.
How much are last minute flights from IAD to SEA?
Last-minute flights from IAD to SEA (booked within 7 days of departure) typically cost noticeably more than fares booked 4–8 weeks out. Booking early is the smarter move.
What is a good round-trip deal from Washington to Seattle?
A good deal is anything at or below the recent fares shown above. Set a free Airfare Deal alert and we'll ping you the moment fares drop.
Which airlines fly from Washington to Seattle?
You'll mainly see United Airlines on Washington to Seattle. Checking each against the live fares below is the surest way to find the lowest price for your dates.
How early should I get to Washington airport for this flight?
Plan on two hours before departure for a domestic flight — ninety minutes can work at smaller airports outside peak times. If you're checking a bag, earlier is better; the bag-drop line, not the flight, is what runs late.
Do the cheapest fares on this route include a checked bag?
Usually not. Basic economy fares on most airlines include a carry-on but charge extra for checked bags, and seat selection can cost more too. Add up the real total before comparing — a slightly higher regular fare sometimes works out cheaper. Our team confirms the full breakdown with you before you pay.
More cheap flights from Washington
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