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Cheap flights from St. Louis to Seattle from $90

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from St. Louis to Seattle departing on 5/6. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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Find the cheapest flights from St. Louis to Seattle

Cheap round-trip flights

KAYAK's recommended round-trip deals from the most popular airlines that fly from St. Louis to Seattle.
Delta Logo
2:15 pm - 10:23 pmSTL-SEA
10h 08m1 stop
Delta Logo
11:50 pm - 10:47 amSEA-STL
8h 57m1 stop
$189Delta
Find Deal
Wed, May 7 - Mon, May 12
Delta Logo
7:15 pm - 12:02 amSTL-SEA
6h 47m1 stop
Delta Logo
10:55 pm - 9:28 amSEA-STL
8h 33m1 stop
$203Delta
Find Deal
Fri, May 2 - Mon, May 5
American Airlines Logo
7:23 am - 2:23 pmSTL-SEA
9h 00m1 stop
American Airlines Logo
11:55 pm - 7:56 amSEA-STL
6h 01m1 stop
$214American Airlines
Find Deal
Thu, Sep 18 - Mon, Sep 22
United Airlines Logo
4:20 pm - 10:50 pmSTL-SEA
8h 30m1 stop
United Airlines Logo
7:15 am - 4:52 pmSEA-STL
7h 37m1 stop
$217United Airlines
Find Deal
Fri, Apr 25 - Wed, Apr 30
American Airlines Logo
5:27 pm - 11:04 pmSTL-SEA
7h 37m1 stop
American Airlines Logo
12:59 am - 10:25 amSEA-STL
7h 26m1 stop
$220American Airlines
Find Deal
Wed, Apr 23 - Fri, Apr 25
United Airlines Logo
1:43 pm - 6:07 pmSTL-SEA
6h 24m1 stop
United Airlines Logo
12:45 pm - 11:48 pmSEA-STL
9h 03m2 stops
$222United Airlines
Find Deal
Fri, Apr 25 - Wed, Apr 30
Frontier Logo
9:55 pm - 6:00 pmSTL-SEA
22h 05m1 stop
Frontier Logo
6:00 am - 9:59 amSEA-STL
25h 59m1 stop
$240Frontier
Find Deal
Sun, May 4 - Tue, May 13
Alaska Airlines Logo
6:30 am - 8:54 amSTL-SEA
4h 24mnonstop
Alaska Airlines Logo
6:03 pm - 11:59 pmSEA-STL
3h 56mnonstop
$243Alaska Airlines
Find Deal
Sun, May 4 - Tue, May 13
Alaska Airlines Logo
3:08 pm - 5:39 pmSTL-SEA
4h 31mnonstop
Alaska Airlines Logo
6:03 pm - 11:59 pmSEA-STL
3h 56mnonstop
$257Alaska Airlines
Find Deal
Wed, Apr 30 - Wed, May 7
Frontier Logo
9:55 pm - 6:00 pmSTL-SEA
22h 05m1 stop
Frontier Logo
8:22 pm - 9:05 pmSEA-STL
22h 43m1 stop
$270Frontier
Find Deal
Sun, May 11 - Sun, May 18

American Airlines flights from St. Louis to Seattle

Our best American Airlines deals on St. Louis to Seattle flight tickets
American Airlines
Sep 18
STL7:23 amLambert-St Louis
9h 00m
1 stop
SEA2:23 pmSeattle/Tacoma Intl
Sep 22
SEA11:55 pmSeattle/Tacoma Intl
6h 01m
1 stop
STL7:56 amLambert-St Louis
American Airlines
Apr 15
STL7:04 amLambert-St Louis
7h 57m
1 stop
SEA1:01 pmSeattle/Tacoma Intl
Apr 24
SEA11:20 amSeattle/Tacoma Intl
8h 52m
1 stop
STL10:12 pmLambert-St Louis
American Airlines
Apr 23
STL5:27 pmLambert-St Louis
7h 37m
1 stop
SEA11:04 pmSeattle/Tacoma Intl
Apr 25
SEA12:59 amSeattle/Tacoma Intl
7h 26m
1 stop
STL10:25 amLambert-St Louis

United Airlines flights from St. Louis to Seattle

Our best United Airlines deals on St. Louis to Seattle flight tickets
United Airlines
Apr 25
STL4:20 pmLambert-St Louis
8h 30m
1 stop
SEA10:50 pmSeattle/Tacoma Intl
Apr 30
SEA7:15 amSeattle/Tacoma Intl
7h 37m
1 stop
STL4:52 pmLambert-St Louis
United Airlines
Apr 25
STL1:43 pmLambert-St Louis
6h 24m
1 stop
SEA6:07 pmSeattle/Tacoma Intl
Apr 30
SEA12:45 pmSeattle/Tacoma Intl
9h 03m
2 stops
STL11:48 pmLambert-St Louis
United Airlines
Apr 15
STL5:35 pmLambert-St Louis
7h 08m
1 stop
SEA10:43 pmSeattle/Tacoma Intl
Apr 18
SEA10:50 amSeattle/Tacoma Intl
8h 58m
1 stop
STL9:48 pmLambert-St Louis

See travel insights to Seattle from

How to get the cheapest flight ticket from St. Louis to Seattle

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the typical price of a round-trip flight between St. Louis and Seattle?

What is the cheapest month to fly to Seattle?

In general, October is the cheapest month to fly from St. Louis to Seattle. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $296. If you don’t want to visit Seattle in October, then you should wait until September to fly from St. Louis, when ticket prices are also cheap, with an average price of $306.

What is the cheapest day to depart on your flight to Seattle?

On average, the least expensive day to fly to Seattle from St. Louis is on a Wednesday. momondo users have found tickets for Wednesday departures for as low as $482. However, this price may fluctuate depending on the airline, the season, and holidays. On the other hand, Saturday is the most expensive day to depart from St. Louis because it is more convenient for both business and leisure travelers. As a result, prices tend to be around $561.

What is the cheapest time of day to depart on your flight to Seattle?

Flying to Seattle from St. Louis in the evening is the least expensive time of day to depart. momondo users have found prices as low as $500 when looking at flights departing in the evening. Flights to Seattle are more costly in the morning, with an average ticket price of $514. Departure times in the morning fall within the peak daily travel times, which is why tickets can be more expensive.

What is the cheapest Lambert-St Louis to Seattle/Tacoma Intl flight route?

Fly from Lambert-St Louis to Seattle/Tacoma Intl for the best Lambert-St Louis - Seattle/Tacoma Intl flight prices

How far in advance should I book a flight to Seattle?

You are more likely to see cheaper flights to Seattle from St. Louis when booking 6 weeks ahead of your departure date. In general, you can expect to find flights to Seattle for around $368 when searching 6 weeks out.However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Seattle from St. Louis for as low as $299 on momondo.

What cabin class options are available on Lambert-St Louis to Seattle/Tacoma Intl flights?

There are 4 cabin classes available to choose from on Lambert-St Louis to Seattle/Tacoma Intl flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

How have St. Louis to Seattle flight prices changed over time?

As of April 2025, prices for St. Louis to Seattle flights are approximately 24% more expensive when compared to flights at the same time last year.

When to book flights from St. Louis to Seattle

Are you open to changing your travel dates? Check out the ideal times to fly from St. Louis to Seattle according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap St. Louis to Seattle (STL to SEA) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from St. Louis to Seattle

Best Price Found

$90

Fastest flight time

4h 24m

Direct flights

Every day

Airports in Seattle

1 airport
The best one-way flight to Seattle from St. Louis in the past 72 hours is $90. The best round-trip flight deal from St. Louis to Seattle found on momondo in the last 72 hours is $189.
The fastest flight from St. Louis to Seattle takes 4h 24m
Direct flights go from St. Louis to Seattle every day.
There is 1 airport near Seattle: Seattle/Tacoma Intl (SEA)

  • How far is Lambert-St Louis to Seattle/Tacoma Intl by plane?

    Lambert-St Louis and Seattle/Tacoma Intl are 1719.6 mi apart from one another. By plane, this route typically takes 4h 24m.

  • When did momondo last update prices for flights from Lambert-St Louis Airport to Seattle/Tacoma Intl Airport?

    Prices for flights from Lambert-St Louis Airport to Seattle/Tacoma Intl Airport are updated daily.

  • How many operators does momondo search for flights from Lambert-St Louis Airport to Seattle/Tacoma Intl Airport?

  • How old do you have to be to fly from Lambert-St Louis Airport to Seattle/Tacoma Intl Airport?

    The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Lambert-St Louis Airport to Seattle/Tacoma Intl Airport.

  • What documentation or ID do you need to fly to Seattle/Tacoma Intl Airport?

    The required travel and health documents for your Seattle/Tacoma Intl Airport trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Seattle/Tacoma Intl Airport. We recommend that you seek guidance from your airline or a reliable third party such as IATA.

  • What is the most popular plane model from St. Louis to Seattle?

  • What is the most popular airline from St. Louis to Seattle?


Best airlines flying from St. Louis to Seattle

Compare and see reviews for airlines that fly from St. Louis to Seattle with momondo
Airline
Rating
Free Cancellation
Price
FrontierPriceFrom $118Free CancellationRating
5.9
3,276 reviews
Search Frontier flights
DeltaPriceFrom $171Free CancellationRating
8.0
7,897 reviews
Search Delta flights
American AirlinesPriceFrom $201Free CancellationRating
7.2
10,000 reviews
Search American Airlines flights
United AirlinesPriceFrom $216Free CancellationRating
7.4
8,616 reviews
Search United Airlines flights
Alaska AirlinesPriceFrom $236Free CancellationRating
8.0
9,827 reviews
Search Alaska Airlines flights
Hawaiian AirlinesPriceFrom $237Free CancellationRating
7.9
2,344 reviews
Search Hawaiian Airlines flights
SouthwestPriceFrom $266Free CancellationRating
8.0
4,274 reviews
Search Southwest flights
  • Alaska Airlines Flights From St. Louis to Seattle

    Alaska Airlines operates around 3 flights from St. Louis to Seattle every week. The average price of these flights found in the last 72 hours has been $413, but momondo users have found Alaska Airlines deals from St. Louis to Seattle from as low as $236 round-trip. Alaska Airlines has been scored 8.0/10 in 9,825 reviews.

  • Hawaiian Airlines Flights From St. Louis to Seattle

    Another popular option for St. Louis to Seattle flights is Hawaiian Airlines (7.9/10, 2,344 ratings). Hawaiian Airlines flies from St. Louis to Seattle around 11 times per week, with deals starting from $237 round-trip and rising to an average price of around $415.


Traveling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
Leavenworth
Tacoma
SeaTac
Ocean Shores
Olympia
Kent
Renton
Federal Way
Tukwila
Puyallup
Kirkland
Lakewood
Lynnwood
Fife
Shoreline
Marysville
Centralia
Redmond
Cle Elum
Lacey

Why use momondo?

Why should I use momondo to find a flight deal from St. Louis to Seattle?

momondo compares prices from hundreds of airlines and agents so you can find and book the best deal on flights from St. Louis to Seattle. Millions of users trust and use momondo every year so you are in good hands.

Can I find flights from St. Louis to Seattle with flexible booking policies on momondo?

Yes. momondo allows you to filter the results for St. Louis to Seattle flights to just show those with flexible booking policies.

How can momondo help me find flights from St. Louis to Seattle?

Once all potential St. Louis to Seattle flight options are in front of you, momondo lets you sort and filter flights based on preferences such as airline, price and flight times amongst many other options.

I’m not ready to book a flight from St. Louis to Seattle right now. Can momondo alert me if prices change?

Of course. momondo tracks the price of St. Louis to Seattle flights. All you need is a valid email address and we will do the rest; it is that quick and easy.


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