Route guide · 1,705 miles
Cheap Flights from St. Louis to Seattle
STL → SEA · Nonstop 3h 58m · Live round-trip fares
Plenty of travelers price out St. Louis to Seattle every day — here's how to beat the average fare. Nonstops run about 3h 58m, and the calendar matters more than the airline. Aim to book 3–6 weeks ahead, stay flexible on the day of the week, and set a free alert so a price drop never slips past you.
Live fares for STL → SEA are updating. Use the search below for real-time prices.
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Flight time
3h 58m
Nonstop, typical
Distance
1,705 mi
STL → SEA
Book ahead
3–6 weeks
Best window, typically
Nonstop airlines
2
American Airlines, Alaska Airlines
Nonstop flights from St. Louis to Seattle
Want to skip the layover? Nonstops from St. Louis to Seattle are flown by American Airlines, Alaska Airlines, getting you there in about 3h 58m. For the lowest fares, book around 3–6 weeks before departure — last-minute nonstops on this route rarely come cheap.
Booking insights: St. Louis → Seattle
- Distance: 1,705 miles · nonstop flight time: 3h 58m.
- Rule of thumb for this route: the sweet spot is usually 3–6 weeks before departure.
- Tuesday and Wednesday departures usually undercut Friday and Sunday fares on routes like this one.
- Set a free Airfare Deal alert instead of checking daily — the best fares can sell out in hours.
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Flying from St. Louis to Seattle: what you need to know
The flight
St. Louis to Seattle is a proper cross-country leg — 1,705 miles and around 3h 58m in the air nonstop. Download entertainment before you board, bring a full water bottle, and think about the time change: even a two-hour shift can leave you groggy if you land late and start early.
Airlines on this route
American Airlines and Alaska Airlines fly 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 St. Louis (STL)
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 St. Louis 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 St. Louis fares — prices on the return direction often move on a different rhythm.
When to book
For a trip of 1,705 miles, booking 3–6 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
- Download the airline's app before you fly; gate changes and delays show up there first.
- Nonstop time on this route is about 3h 58m — a one-stop itinerary needs to be a lot cheaper to be worth the extra hours.
- Tuesday and Wednesday departures are typically the cheapest days on domestic routes.
- 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.
St. Louis to Seattle flight FAQs
How long is the flight from STL to SEA?
Plan on about 3h 58m in the air for a nonstop from St. Louis to Seattle — the route runs roughly 1,705 miles. Connecting flights typically add 2–4 hours.
Are there nonstop flights from St. Louis to Seattle?
Yes — look for American Airlines, Alaska Airlines on this route. Nonstop seats are usually priced best 3–6 weeks before departure.
What is the cheapest month to fly from St. Louis to Seattle?
Fares from St. Louis to Seattle tend to ease outside the peak summer and holiday rush — the late-summer and early-fall shoulder weeks are usually kinder on the wallet. Set a free Airfare Deal alert and we'll flag the dips for your dates.
How much are last minute flights from STL to SEA?
Book inside the final week and you'll usually pay a premium on STL to SEA. Fares booked 3–6 weeks ahead are almost always kinder.
What is a good round-trip deal from St. Louis 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 St. Louis to Seattle?
The main carriers on this route are American Airlines, Alaska Airlines. Comparing all of them on the live search below usually surfaces the lowest fare for your dates.
How early should I get to St. Louis 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 St. Louis
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