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Cheap flights from St. Louis to Seattle from $74

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 9/19. 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 (STL-SEA)

Cheap round-trip flights

Frontier Logo
7:52 pm - 12:07 pmSTL-SEA
18h 15m1 stop
Frontier Logo
1:02 pm - 9:07 amSEA-STL
18h 05m1 stop
$243Frontier
Find Deal
Fri, Oct 10 - Tue, Oct 14
Hawaiian Airlines Logo
6:00 am - 8:30 amSTL-SEA
4h 30mnonstop
Hawaiian Airlines Logo
6:02 pm - 12:03 amSEA-STL
4h 01mnonstop
$244Hawaiian Airlines
Find Deal
Sat, Sep 27 - Mon, Oct 6
Frontier Logo
7:54 pm - 11:01 pmSTL-SEA
29h 07m1 stop
Frontier Logo
7:00 am - 9:06 amSEA-STL
24h 06m1 stop
$245Frontier
Find Deal
Tue, Sep 2 - Sat, Sep 13
Delta Logo
5:30 pm - 10:14 pmSTL-SEA
6h 44m1 stop
Delta Logo
11:55 pm - 10:37 amSEA-STL
8h 42m1 stop
$247Delta
Find Deal
Wed, Sep 3 - Tue, Sep 9
Southwest Logo
9:20 am - 11:40 amSTL-SEA
4h 20mnonstop
Southwest Logo
8:40 pm - 8:30 amSEA-STL
9h 50m1 stop
$248Southwest
Find Deal
Sat, Sep 27 - Sun, Sep 28
Delta Logo
5:30 pm - 9:58 pmSTL-SEA
6h 28m1 stop
Delta Logo
9:25 am - 12:38 amSEA-STL
13h 13m2 stops
$251Delta
Find Deal
Sat, Sep 20 - Tue, Sep 23
Southwest Logo
6:55 pm - 12:50 amSTL-SEA
7h 55m1 stop
Southwest Logo
9:35 am - 7:20 pmSEA-STL
7h 45m2 stops
$254Southwest
Find Deal
Mon, Oct 13 - Fri, Oct 17
American Airlines Logo
5:17 am - 10:44 amSTL-SEA
7h 27m1 stop
American Airlines Logo
12:59 am - 10:37 amSEA-STL
7h 38m1 stop
$264American Airlines
Find Deal
Thu, Nov 13 - Sat, Nov 15
American Airlines Logo
5:23 am - 11:56 amSTL-SEA
8h 33m1 stop
American Airlines Logo
12:27 am - 9:57 amSEA-STL
7h 30m1 stop
$278American Airlines
Find Deal
Tue, Jan 13 - Mon, Jan 19
Alaska Airlines Logo
7:00 am - 9:33 amSTL-SEA
4h 33mnonstop
Alaska Airlines Logo
8:34 am - 2:27 pmSEA-STL
3h 53mnonstop
$288Alaska Airlines
Find Deal
Tue, Nov 18 - Tue, Dec 2

Frontier flights from St. Louis to Seattle

Our best Frontier deals on St. Louis to Seattle flight tickets
Frontier
Oct 10
STL7:52 pmLambert-St Louis
18h 15m
1 stop
SEA12:07 pmSeattle/Tacoma Intl
Oct 14
SEA1:02 pmSeattle/Tacoma Intl
18h 05m
1 stop
STL9:07 amLambert-St Louis
$243
Find similar
Frontier
Sep 2
STL7:54 pmLambert-St Louis
29h 07m
1 stop
SEA11:01 pmSeattle/Tacoma Intl
Sep 13
SEA7:00 amSeattle/Tacoma Intl
24h 06m
1 stop
STL9:06 amLambert-St Louis
$245
Find similar
Frontier
Aug 25
STL7:54 pmLambert-St Louis
29h 07m
1 stop
SEA11:01 pmSeattle/Tacoma Intl
Aug 27
SEA6:41 amSeattle/Tacoma Intl
24h 30m
1 stop
STL9:11 amLambert-St Louis
$248
Find similar

Hawaiian Airlines flights from St. Louis to Seattle

Our best Hawaiian Airlines deals on St. Louis to Seattle flight tickets
Hawaiian Airlines
Sep 27
STL6:00 amLambert-St Louis
4h 30m
SEA8:30 amSeattle/Tacoma Intl
Oct 6
SEA6:02 pmSeattle/Tacoma Intl
4h 01m
STL12:03 amLambert-St Louis
$244
Find similar
Hawaiian Airlines
Sep 18
STL6:30 pmLambert-St Louis
4h 29m
SEA8:59 pmSeattle/Tacoma Intl
Sep 25
SEA6:03 pmSeattle/Tacoma Intl
3h 56m
STL11:59 pmLambert-St Louis
$249
Find similar
Hawaiian Airlines
Sep 27
STL3:35 pmLambert-St Louis
4h 19m
SEA5:54 pmSeattle/Tacoma Intl
Oct 6
SEA6:02 pmSeattle/Tacoma Intl
4h 01m
STL12:03 amLambert-St Louis
$252
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 August 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

Fri 10/10

7:52 pm-12:07 pm

1 stop18h 15m

Seattle/Tacoma Intl

Tue 10/14

1:02 pm-9:07 am

1 stop18h 05m

$243

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Sat 9/27

6:00 am-8:30 am

Nonstop4h 30m

Seattle/Tacoma Intl

Mon 10/6

6:02 pm-12:03 am

Nonstop4h 01m

$244

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 9/2

7:54 pm-11:01 pm

1 stop29h 07m

Seattle/Tacoma Intl

Sat 9/13

7:00 am-9:06 am

1 stop24h 06m

$245

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Wed 9/3

5:30 pm-10:14 pm

1 stop6h 44m

Seattle/Tacoma Intl

Tue 9/9

11:55 pm-10:37 am

1 stop8h 42m

$247

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Sat 9/27

9:20 am-11:40 am

Nonstop4h 20m

Seattle/Tacoma Intl

Sun 9/28

8:40 pm-8:30 am

1 stop9h 50m

$248

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Sat 9/20

5:30 pm-9:58 pm

1 stop6h 28m

Seattle/Tacoma Intl

Tue 9/23

9:25 am-12:38 am

2 stops13h 13m

$251

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Mon 10/13

6:55 pm-12:50 am

1 stop7h 55m

Seattle/Tacoma Intl

Fri 10/17

9:35 am-7:20 pm

2 stops7h 45m

$254

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Thu 11/13

5:17 am-10:44 am

1 stop7h 27m

Seattle/Tacoma Intl

Sat 11/15

12:59 am-10:37 am

1 stop7h 38m

$264

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 1/13

5:23 am-11:56 am

1 stop8h 33m

Seattle/Tacoma Intl

Mon 1/19

12:27 am-9:57 am

1 stop7h 30m

$278

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 11/18

7:00 am-9:33 am

Nonstop4h 33m

Seattle/Tacoma Intl

Tue 12/2

8:34 am-2:27 pm

Nonstop3h 53m

$288

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, September 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 $276. If you don’t want to visit Seattle in September, then you should wait until October to fly from St. Louis, when ticket prices are also cheap, with an average price of $289.

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 $468. 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 $558.

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 $448 when looking at flights departing in the afternoon. Flights to Seattle are more costly in the morning, with an average ticket price of $513. 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 weeks ahead of your departure date. In general, you can expect to find flights to Seattle for around $356 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 $284 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 12% 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 August 2025, prices for St. Louis to Seattle flights are approximately 13% 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

$169

Fastest flight time

4h 19m

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 $169. The best round-trip flight deal from St. Louis to Seattle found on momondo in the last 72 hours is $333.
The fastest flight from St. Louis to Seattle takes 4h 19m
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 19m.

  • 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
7,981 reviews
Search Delta flights
FrontierPriceFrom $100Free CancellationRating
5.8
3,207 reviews
Search Frontier flights
SouthwestPriceFrom $179Free CancellationRating
8.0
4,245 reviews
Search Southwest flights
American AirlinesPriceFrom $188Free CancellationRating
7.2
10,000 reviews
Search American Airlines flights
United AirlinesPriceFrom $216Free CancellationRating
7.4
8,930 reviews
Search United Airlines flights
Alaska AirlinesPriceFrom $236Free CancellationRating
8.0
10,000 reviews
Search Alaska Airlines flights
Hawaiian AirlinesPriceFrom $237Free CancellationRating
7.8
2,672 reviews
Search Hawaiian Airlines flights

  • Southwest Flights From St. Louis to Seattle

    Southwest 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 $386, but momondo users have found Southwest deals from St. Louis to Seattle from as low as $179 round-trip. Southwest has been scored 8.0/10 in 4,245 reviews.

  • Alaska Airlines Flights From St. Louis to Seattle

    Another popular option for St. Louis to Seattle flights is Alaska Airlines (8.0/10, 10,000 ratings). Alaska Airlines flies from St. Louis to Seattle around 9 times per week, with deals starting from $236 round-trip and rising to an average price of around $394.

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
Renton
Kent
Lynnwood
Federal Way
Marysville
Puyallup
Tukwila
Kirkland
Lakewood
Centralia
Cle Elum
Shoreline
Fife
Redmond
Westport

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.

An easier way to manage your Seattle trip

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