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Cheap flights from St. Louis to Seattle from $64

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 2/11. 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

Enter your travel dates to find the best prices.
United Airlines Logo
1:35 pm - 6:25 pmSTL-SEA
6h 50m1 stop
United Airlines Logo
7:00 am - 3:40 pmSEA-STL
6h 40m1 stop
$202United Airlines
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Thu, Dec 4 - Sat, Dec 13
American Airlines Logo
2:06 pm - 9:09 pmSTL-SEA
9h 03m1 stop
American Airlines Logo
12:59 am - 11:00 amSEA-STL
8h 01m1 stop
$207American Airlines
Find Deal
Tue, Feb 24 - Sat, Feb 28
United Airlines Logo
1:35 pm - 9:00 pmSTL-SEA
9h 25m2 stops
United Airlines Logo
7:00 am - 3:40 pmSEA-STL
6h 40m1 stop
$208United Airlines
Find Deal
Thu, Dec 4 - Sat, Dec 13
Delta Logo
7:30 am - 2:45 pmSTL-SEA
9h 15m1 stop
Delta Logo
6:05 am - 2:31 pmSEA-STL
6h 26m1 stop
$209Delta
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Tue, Apr 21 - Sat, Apr 25
Southwest Logo
4:30 pm - 10:55 pmSTL-SEA
8h 25m1 stop
Southwest Logo
5:15 am - 5:15 pmSEA-STL
10h 00m2 stops
$212Southwest
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Mon, Dec 8 - Wed, Dec 10
Frontier Logo
7:43 pm - 12:14 pmSTL-SEA
18h 31m1 stop
Frontier Logo
12:48 pm - 9:47 amSEA-STL
18h 59m2 stops
$216Frontier
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Wed, Dec 3 - Sat, Dec 6
Alaska Airlines Logo
2:50 pm - 5:25 pmSTL-SEA
4h 35mnonstop
Alaska Airlines Logo
7:55 am - 1:54 pmSEA-STL
3h 59mnonstop
$217Alaska Airlines
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Wed, Jan 14 - Tue, Jan 20
Delta Logo
7:00 am - 12:33 pmSTL-SEA
7h 33m1 stop
Delta Logo
1:38 pm - 9:35 pmSEA-STL
5h 57m1 stop
$218Delta
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Thu, Jan 8 - Mon, Jan 12
Frontier Logo
7:43 pm - 11:53 amSTL-SEA
18h 10m1 stop
Frontier Logo
3:40 pm - 10:33 pmSEA-STL
28h 53m2 stops
$222Frontier
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Fri, Dec 12 - Mon, Dec 15
Frontier Logo
10:10 pm - 10:11 amSTL-SEA
14h 01m1 stop
Frontier Logo
6:33 pm - 9:25 pmSEA-STL
24h 52m1 stop
$224Frontier
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Sun, Dec 21 - Mon, Dec 29

Delta flights from St. Louis to Seattle

Our best Delta deals on St. Louis to Seattle flight tickets
Delta
Apr 21
STL7:30 amLambert-St Louis
9h 15m
1 stop
SEA2:45 pmSeattle/Tacoma Intl
Apr 25
SEA6:05 amSeattle/Tacoma Intl
6h 26m
1 stop
STL2:31 pmLambert-St Louis
$209
Find similar
Delta
Jan 8
STL7:00 amLambert-St Louis
7h 33m
1 stop
SEA12:33 pmSeattle/Tacoma Intl
Jan 12
SEA1:38 pmSeattle/Tacoma Intl
5h 57m
1 stop
STL9:35 pmLambert-St Louis
$218
Find similar
Delta
Dec 18
STL6:15 amLambert-St Louis
8h 42m
1 stop
SEA12:57 pmSeattle/Tacoma Intl
Dec 31
SEA10:55 pmSeattle/Tacoma Intl
8h 29m
1 stop
STL9:24 amLambert-St Louis
$228
Find similar

Southwest flights from St. Louis to Seattle

Our best Southwest deals on St. Louis to Seattle flight tickets
Southwest
Dec 8
STL4:30 pmLambert-St Louis
8h 25m
1 stop
SEA10:55 pmSeattle/Tacoma Intl
Dec 10
SEA5:15 amSeattle/Tacoma Intl
10h 00m
2 stops
STL5:15 pmLambert-St Louis
$212
Find similar
Southwest
Dec 5
STL5:25 pmLambert-St Louis
7h 30m
1 stop
SEA10:55 pmSeattle/Tacoma Intl
Dec 29
SEA8:35 pmSeattle/Tacoma Intl
9h 40m
1 stop
STL8:15 amLambert-St Louis
$248
Find similar
Southwest
Dec 23
STL7:05 pmLambert-St Louis
8h 20m
1 stop
SEA1:25 amSeattle/Tacoma Intl
Dec 28
SEA6:45 amSeattle/Tacoma Intl
8h 45m
1 stop
STL5:30 pmLambert-St Louis
$253
Find similar

momondo Fare Finder

 
Customize your flight search to find flights from St. Louis to Seattle that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, momondo users made 832,500 searches. Data last updated November 21, 2025.
Use the filters below to find and compare flights from St. Louis to Seattle that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Thu 12/4

1:35 pm-6:25 pm

1 stop6h 50m

Seattle/Tacoma Intl

Sat 12/13

7:00 am-3:40 pm

1 stop6h 40m

$202

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 2/24

2:06 pm-9:09 pm

1 stop9h 03m

Seattle/Tacoma Intl

Sat 2/28

12:59 am-11:00 am

1 stop8h 01m

$207

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Thu 12/4

1:35 pm-9:00 pm

2 stops9h 25m

Seattle/Tacoma Intl

Sat 12/13

7:00 am-3:40 pm

1 stop6h 40m

$208

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 4/21

7:30 am-2:45 pm

1 stop9h 15m

Seattle/Tacoma Intl

Sat 4/25

6:05 am-2:31 pm

1 stop6h 26m

$209

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Mon 12/8

4:30 pm-10:55 pm

1 stop8h 25m

Seattle/Tacoma Intl

Wed 12/10

5:15 am-5:15 pm

2 stops10h 00m

$212

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Wed 12/3

7:43 pm-12:14 pm

1 stop18h 31m

Seattle/Tacoma Intl

Sat 12/6

12:48 pm-9:47 am

2 stops18h 59m

$216

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Wed 1/14

2:50 pm-5:25 pm

Nonstop4h 35m

Seattle/Tacoma Intl

Tue 1/20

7:55 am-1:54 pm

Nonstop3h 59m

$217

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Thu 1/8

7:00 am-12:33 pm

1 stop7h 33m

Seattle/Tacoma Intl

Mon 1/12

1:38 pm-9:35 pm

1 stop5h 57m

$218

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Fri 12/12

7:43 pm-11:53 am

1 stop18h 10m

Seattle/Tacoma Intl

Mon 12/15

3:40 pm-10:33 pm

2 stops28h 53m

$222

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Sun 12/21

10:10 pm-10:11 am

1 stop14h 01m

Seattle/Tacoma Intl

Mon 12/29

6:33 pm-9:25 pm

1 stop24h 52m

$224

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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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 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 $249. 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 $296.

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 Tuesday. momondo users have found tickets for Tuesday departures for as low as $458. However, this price may fluctuate depending on the airline, the season, and holidays. On the other hand, Sunday 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 $569.

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

Flying to Seattle from St. Louis in the afternoon is the least expensive time of day to depart. momondo users have found prices as low as $447 when looking at flights departing in the afternoon. Flights to Seattle are more costly at noon, with an average ticket price of $526. Departure times at noon 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 weeks ahead of your departure date. In general, you can expect to find flights to Seattle for around $348 when searching 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 $296 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.

Can stopping save me money on St. Louis to Seattle flights?

You could potentially save up to 20% on your flight if you consider stops on a St. Louis to Seattle flight.

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

As of November 2025, prices for St. Louis to Seattle flights are approximately 1% cheaper 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

$267

Fastest flight time

4h 26m

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 $267. The best round-trip flight deal from St. Louis to Seattle found on momondo in the last 72 hours is $348.
The fastest flight from St. Louis to Seattle takes 4h 26m
Direct flights go from St. Louis to Seattle every day.
There is 1 airport near Seattle: Seattle/Tacoma Intl (SEA)
Search flight deals

  • 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 26m.

  • 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
DeltaPriceFrom $94Free CancellationRating
7.9
8,002 reviews
Search Delta flights
FrontierPriceFrom $120Free CancellationRating
5.8
3,102 reviews
Search Frontier flights
SouthwestPriceFrom $176Free CancellationRating
8.0
4,251 reviews
Search Southwest flights
American AirlinesPriceFrom $188Free CancellationRating
7.2
11,047 reviews
Search American Airlines flights
United AirlinesPriceFrom $216Free CancellationRating
7.4
9,030 reviews
Search United Airlines flights
Hawaiian AirlinesPriceFrom $237Free CancellationRating
7.8
2,811 reviews
Search Hawaiian Airlines flights
Alaska AirlinesPriceFrom $240Free CancellationRating
8.0
11,326 reviews
Search Alaska Airlines 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 $390, but momondo users have found Alaska Airlines deals from St. Louis to Seattle from as low as $240 round-trip. Alaska Airlines has been scored 8.0/10 in 11,327 reviews.

  • Hawaiian Airlines Flights From St. Louis to Seattle

    Another popular option for St. Louis to Seattle flights is Hawaiian Airlines (7.8/10, 2,811 ratings). Hawaiian Airlines flies from St. Louis to Seattle around 3 times per week, with deals starting from $237 round-trip and rising to an average price of around $380.

Traveling to a place near Seattle?

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

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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