$94+ Cheap flights from St. Louis to Seattle (STL - SEA)
This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 10/31. Fares are subject to change and may not be available on all flights or dates of travel.
STL — SEA
Sep 5 — Sep 121
Round-trip
1 adult, Economy
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Find cheap flights from St. Louis to Seattle with Cheapflights
1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.Cheapflights Tip: The best prices from Lambert-St Louis to Seattle/Tacoma Intl are usually found in February or March, booked 44 days in advance, depart on a Friday or Thursday and return on a Tuesday
Cheap flight deals from St. Louis to Seattle
Cheapest
Best
Last-minute
One-way
Cheapest flights from St. Louis to SeattleExplore the most affordable flight options available from St. Louis to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 6, 2026.
Explore the most affordable flight options available from St. Louis to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 6, 2026.
This Southwest deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/64:20 pm -
1 stop8h 45m
Wed 9/911:05 pm -
1 stop8h 10m
Deal found 8/6![Southwest logo]()
$297
This CheapOair deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/276:45 pm -
1 stop17h 54m
Sun 8/309:29 pm -
1 stop18h 21m
Deal found 8/6![Frontier logo]()
$298
This Kiwi.com deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/277:58 pm -
1 stop15h 21m
Wed 9/27:06 pm -
2 stops20h 16m
Deal found 8/6![Frontier logo]()
$303
This Kiwi.com deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/317:58 pm -
1 stop15h 21m
Sun 9/139:45 pm -
1 stop11h 32m
Deal found 8/6![Frontier logo]()
$304
This Kiwi.com deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/247:58 pm -
1 stop15h 21m
Wed 8/267:06 pm -
1 stop22h 07m
Deal found 8/6![Frontier logo]()
$305
This Trip.com deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/16:45 pm -
1 stop17h 54m
Tue 9/88:48 pm -
1 stop12h 44m
Deal found 8/6![Frontier logo]()
$313
This Kiwi.com deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/307:58 pm -
1 stop15h 21m
Mon 9/149:45 pm -
1 stop11h 47m
Deal found 8/6![Frontier logo]()
$317
This CheapOair deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/26:45 pm -
1 stop22h 43m
Sat 9/52:37 pm -
1 stop26h 36m
Deal found 8/6![Frontier logo]()
$318
This Kiwi.com deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/115:19 pm -
1 stop18h 41m
Sun 10/189:16 pm -
1 stop26h 01m
Deal found 8/6![Frontier logo]()
$320
This American Airlines deal was found by Cheapflights users on 8/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/193:34 pm -
1 stop8h 18m
Sun 9/203:41 pm -
1 stop6h 46m
Deal found 8/5![American Airlines logo]()
$322
This Expedia deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/1112:17 pm -
1 stop8h 11m
Sat 9/198:13 am -
Nonstop4h 08m
Deal found 8/6![Multiple Airlines logo]()
$323
This Kiwi.com deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/226:45 pm -
1 stop17h 54m
Wed 8/267:06 pm -
1 stop22h 07m
Deal found 8/6![Frontier logo]()
$324
Best flights from St. Louis to SeattleDiscover carefully curated flight deals from St. Louis to Seattle that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated August 6, 2026.
Discover carefully curated flight deals from St. Louis to Seattle that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated August 6, 2026.
This Southwest deal was found by Cheapflights users on 8/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/25:50 pm -
2 stops8h 45m
Sat 10/1012:10 am -
1 stop7h 15m
Deal found 8/4![Southwest logo]()
$342
This Alaska Airlines deal was found by Cheapflights users on 8/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/226:08 pm -
1 stop6h 31m
Tue 10/136:03 pm -
Nonstop3h 56m
Deal found 8/3![Alaska Airlines logo]()
$347
This United Airlines deal was found by Cheapflights users on 8/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/108:00 am -
2 stops14h 37m
Wed 10/147:00 am -
1 stop6h 21m
Deal found 8/2![United Airlines logo]()
$362
This Southwest deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/123:00 pm -
2 stops8h 30m
Mon 9/1411:05 pm -
1 stop8h 30m
Deal found 8/6![Southwest logo]()
$343
This Alaska Airlines deal was found by Cheapflights users on 8/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/236:08 pm -
1 stop6h 31m
Sat 9/2612:35 pm -
Nonstop4h 03m
Deal found 8/4![Alaska Airlines logo]()
$367
This Southwest deal was found by Cheapflights users on 8/1. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/298:25 am -
1 stop7h 55m
Sun 9/65:10 am -
2 stops8h 40m
Deal found 8/1![Southwest logo]()
$358
This United Airlines deal was found by Cheapflights users on 8/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/85:30 pm -
1 stop7h 15m
Tue 9/156:32 am -
2 stops13h 28m
Deal found 8/3![United Airlines logo]()
$402
This Alaska Airlines deal was found by Cheapflights users on 8/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/196:29 am -
Nonstop4h 27m
Fri 9/258:13 am -
Nonstop4h 08m
Deal found 8/5![Alaska Airlines logo]()
$392
This Alaska Airlines deal was found by Cheapflights users on 8/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/196:29 am -
Nonstop4h 27m
Thu 9/2412:35 pm -
Nonstop4h 03m
Deal found 8/5![Alaska Airlines logo]()
$392
This Alaska Airlines deal was found by Cheapflights users on 8/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/196:29 am -
Nonstop4h 27m
Mon 9/216:03 pm -
Nonstop3h 56m
Deal found 8/4![Alaska Airlines logo]()
$392
This Alaska Airlines deal was found by Cheapflights users on 8/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/236:29 am -
Nonstop4h 27m
Mon 9/288:13 am -
Nonstop4h 08m
Deal found 8/5![Alaska Airlines logo]()
$392
This Alaska Airlines deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/26:08 pm -
1 stop6h 31m
Tue 9/88:13 am -
Nonstop4h 08m
Deal found 8/6![Alaska Airlines logo]()
$402
Last-minute flights from St. Louis to SeattleDiscover last-minute flight deals from St. Louis to Seattle. Data last updated August 6, 2026 and is based on user searches.
Discover last-minute flight deals from St. Louis to Seattle. Data last updated August 6, 2026 and is based on user searches.
This CheapOair deal was found by Cheapflights users on 8/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/217:58 pm -
1 stop19h 24m
Mon 8/319:29 pm -
1 stop18h 21m
Deal found 8/3![Frontier logo]()
$333
This Kiwi.com deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/247:58 pm -
1 stop15h 21m
Wed 8/267:06 pm -
1 stop22h 07m
Deal found 8/6![Frontier logo]()
$305
This Kiwi.com deal was found by Cheapflights users on 8/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/247:58 pm -
1 stop15h 21m
Wed 9/212:42 pm -
Nonstop3h 56m
Deal found 8/3![Multiple Airlines logo]()
$334
This Kiwi.com deal was found by Cheapflights users on 8/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/277:58 pm -
1 stop15h 21m
Mon 8/319:29 pm -
2 stops17h 02m
Deal found 8/5![Frontier logo]()
$329
This Kiwi.com deal was found by Cheapflights users on 8/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/307:58 pm -
1 stop15h 21m
Thu 9/108:15 pm -
2 stops14h 55m
Deal found 8/5![Frontier logo]()
$324
This Trip.com deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/16:45 pm -
1 stop17h 54m
Tue 9/88:48 pm -
1 stop12h 44m
Deal found 8/6![Frontier logo]()
$313
This Delta deal was found by Cheapflights users on 8/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/110:33 am -
1 stop10h 12m
Wed 9/167:15 am -
1 stop8h 22m
Deal found 8/4![Delta logo]()
$332
This CheapOair deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/26:45 pm -
1 stop22h 43m
Sat 9/52:37 pm -
1 stop26h 36m
Deal found 8/6![Frontier logo]()
$318
This Kiwi.com deal was found by Cheapflights users on 8/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/26:45 pm -
1 stop17h 54m
Wed 9/99:45 pm -
2 stops37h 25m
Deal found 8/5![Frontier logo]()
$331
This Expedia deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/1112:17 pm -
1 stop8h 11m
Sat 9/198:13 am -
Nonstop4h 08m
Deal found 8/6![Multiple Airlines logo]()
$323
This Expedia deal was found by Cheapflights users on 8/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/166:29 am -
Nonstop4h 27m
Wed 9/239:45 pm -
1 stop11h 32m
Deal found 8/5![Multiple Airlines logo]()
$328
This American Airlines deal was found by Cheapflights users on 8/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/193:34 pm -
1 stop8h 18m
Sun 9/203:41 pm -
1 stop6h 46m
Deal found 8/5![American Airlines logo]()
$322
One-way flights from St. Louis to SeattleSearch for one-way flight options from St. Louis to Seattle. Find affordable one-way fares based on user searches. Data last updated August 6, 2026.
Search for one-way flight options from St. Louis to Seattle. Find affordable one-way fares based on user searches. Data last updated August 6, 2026.
This Delta deal was found by Cheapflights users on 8/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/3010:29 am -
1 stop10h 16m
Deal found 8/3![Delta logo]()
$94
This Southwest deal was found by Cheapflights users on 8/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/285:20 am -
2 stops10h 15m
Deal found 8/3![Southwest logo]()
$99
This Delta deal was found by Cheapflights users on 8/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/68:00 am -
1 stop8h 50m
Deal found 8/3![Delta logo]()
$104
This United Airlines deal was found by Cheapflights users on 8/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/61:00 pm -
1 stop9h 45m
Deal found 8/4![United Airlines logo]()
$114
This Southwest deal was found by Cheapflights users on 8/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/55:50 pm -
2 stops8h 45m
Deal found 8/6![Southwest logo]()
$119
This Kiwi.com deal was found by Cheapflights users on 8/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/277:58 pm -
1 stop15h 21m
Deal found 8/5![Frontier logo]()
$126
This Delta deal was found by Cheapflights users on 8/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/97:00 pm -
1 stop6h 59m
Deal found 8/3![Delta logo]()
$130
This Southwest deal was found by Cheapflights users on 8/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/52:25 pm -
2 stops10h 35m
Deal found 8/3![Southwest logo]()
$134
This Kiwi.com deal was found by Cheapflights users on 8/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/168:10 pm -
2 stops48h 16m
Deal found 8/5![Frontier logo]()
$135
This Delta deal was found by Cheapflights users on 8/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/165:47 pm -
1 stop8h 08m
Deal found 8/4![Delta logo]()
$140
Find flight deals from St. Louis to Seattle
Discover tips and strategies to find the most affordable flight options for your journey from St. Louis (STL) to Seattle (SEA). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated August 6, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $297 (Southwest) |
One-way from | $94 (Delta) |
Popular in | July |
Cheapest in | February |
Average price | $437 |
Good round-trip deal | $440 or less |
Good one-way deal | $288 or less |
Cheapflights 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, Cheapflights users made 2,558,603 searches. Data last updated August 6, 2026.
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
Cheapest round-trip
St. LouisSeattle
STL Lambert-St Louis - SEA Seattle/Tacoma Intl
STLSEA
Lambert-St Louis
Fri 10/2
5:50 pm-12:35 am
2 stops8h 45m
Seattle/Tacoma Intl
Sat 10/10
12:10 am-9:25 am
1 stop7h 15m
$342
St. LouisSeattle
STL Lambert-St Louis - SEA Seattle/Tacoma Intl
STLSEA
Lambert-St Louis
Sat 9/12
3:00 pm-9:30 pm
2 stops8h 30m
Seattle/Tacoma Intl
Mon 9/14
11:05 pm-9:35 am
1 stop8h 30m
$343
St. LouisSeattle
STL Lambert-St Louis - SEA Seattle/Tacoma Intl
STLSEA
Lambert-St Louis
Tue 9/22
6:08 pm-10:39 pm
1 stop6h 31m
Seattle/Tacoma Intl
Tue 10/13
6:03 pm-11:59 pm
Nonstop3h 56m
$347
St. LouisSeattle
STL Lambert-St Louis - SEA Seattle/Tacoma Intl
STLSEA
Lambert-St Louis
Sat 8/29
8:25 am-2:20 pm
1 stop7h 55m
Seattle/Tacoma Intl
Sun 9/6
5:10 am-3:50 pm
2 stops8h 40m
$358
St. LouisSeattle
STL Lambert-St Louis - SEA Seattle/Tacoma Intl
STLSEA
Lambert-St Louis
Sat 10/10
8:00 am-8:37 pm
2 stops14h 37m
Seattle/Tacoma Intl
Wed 10/14
7:00 am-3:21 pm
1 stop6h 21m
$362
St. LouisSeattle
STL Lambert-St Louis - SEA Seattle/Tacoma Intl
STLSEA
Lambert-St Louis
Wed 9/23
6:08 pm-10:39 pm
1 stop6h 31m
Seattle/Tacoma Intl
Sat 9/26
12:35 pm-6:38 pm
Nonstop4h 03m
$367
St. LouisSeattle
STL Lambert-St Louis - SEA Seattle/Tacoma Intl
STLSEA
Lambert-St Louis
Sat 9/19
6:29 am-8:56 am
Nonstop4h 27m
Seattle/Tacoma Intl
Fri 9/25
8:13 am-2:21 pm
Nonstop4h 08m
$392
St. LouisSeattle
STL Lambert-St Louis - SEA Seattle/Tacoma Intl
STLSEA
Lambert-St Louis
Sat 9/19
6:29 am-8:56 am
Nonstop4h 27m
Seattle/Tacoma Intl
Thu 9/24
12:35 pm-6:38 pm
Nonstop4h 03m
$392
Quickest round-trip
St. LouisSeattle
STL Lambert-St Louis - SEA Seattle/Tacoma Intl
STLSEA
Lambert-St Louis
Sat 9/19
6:29 am-8:56 am
Nonstop4h 27m
Seattle/Tacoma Intl
Mon 9/21
6:03 pm-11:59 pm
Nonstop3h 56m
$392
St. LouisSeattle
STL Lambert-St Louis - SEA Seattle/Tacoma Intl
STLSEA
Lambert-St Louis
Wed 9/23
6:29 am-8:56 am
Nonstop4h 27m
Seattle/Tacoma Intl
Mon 9/28
8:13 am-2:21 pm
Nonstop4h 08m
$392
Showing 1-10 of 20 resultsSorted by cheapest first
Compare providers for flights from St. Louis to Seattle
Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from St. Louis to Seattle in August.
| Provider | Price Accuracy | Trust Score* |
|---|---|---|
| Price Accuracy1 star | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy- | Trust Score*1 star | |
| Price Accuracy1 star | Trust Score*3 stars |
- Most accurate provider: When it comes to deals on St. Louis-Seattle flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on St. Louis-Seattle flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from St. Louis-Seattle flight searches over the past month and is updated monthly.
- Most trusted provider: When it comes to deals on St. Louis-Seattle flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for St. Louis-Seattle flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.
Best time to book a flight from St. Louis to Seattle
Have a flexible travel schedule? Discover the best time to fly to Seattle from St. Louis with our price prediction graph.
STL-SEA
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.
Cheapflights Insights
Everything you need to know about your flight from St. Louis to Seattle
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How far ahead should I book a flight from St. Louis to Seattle?
The best time to book flights from St. Louis to Seattle is 43 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.
What is the cheapest month to book a flight from St. Louis to Seattle?
Currently, February is the cheapest month in which you can book a flight from St. Louis to Seattle (average of $237). Flying from St. Louis to Seattle in July is currently the most expensive (average of $523). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.
What is the cheapest time of day to fly from STL to SEA?
Find hourly flight availability from St. Louis to Seattle. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated August 6, 2026.
Unlike at noon, when flights are generally more expensive, you can save up to 16% on flights from St. Louis to Seattle by exploring options for tickets in the afternoon.
What is the cheapest day to fly from St. Louis to Seattle?
Use this chart to determine the cheapest time to fly round-trip from St. Louis to Seattle. Price data was last updated on August 1, 2026.
Travelers seeking maximum savings on their St. Louis to Seattle flight should consider departing on Thursday afternoons when fares are most often at their lowest. Monday at noon flights should be avoided if possible as fares are typically the most expensive at this time.
What’s the top layover airport for flights from St. Louis to Seattle?
Share of 1-stop round-trip flights from St. Louis to Seattle chosen by Cheapflights users in the past 12 months, using the same layover each way.
Chicago (ORD) – chosen by Cheapflights users on 25% of 1-stop itineraries from St. Louis to Seattle on Cheapflights.
What’s the cheapest layover airport for flights from St. Louis to Seattle?
Average round-trip fare for 1-stop flights from St. Louis to Seattle, chosen by Cheapflights users in the past 12 months, with the same layover each way.
Denver (DEN) is the most affordable 1-stop option, with an average round-trip price of $248.
What’s the fastest layover option from St. Louis to Seattle?
Shortest average travel time for 1-stop one-way flights from St. Louis to Seattle, based on itineraries clicked by Cheapflights users over the past 12 months, grouped by layover airport.
Flights via Chicago (ORD) have the shortest average one-way travel time for 1-stop routes: 7h 15m.
Which airport typically offers the quickest layover for flights from St. Louis to Seattle?
Average layover duration for 1-stop one-way flights from St. Louis to Seattle, chosen by Cheapflights users in the last 12 months, grouped by stopover airport.
Flights via Chicago (ORD) offer the fastest connection on this route, with an average layover time of 0h 56m.
The best insider tips for St. Louis to Seattle flights
AI-powered summary based on content written by travel experts. AI can make mistakes.
Cheapflights partnered with top experts to bring you the best recommendations for your St. Louis to Seattle trip
Our travel experts
Reviews of airlines servicing Seattle
Get insights into the airlines that provide service to Seattle. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Seattle. Reviews last updated August 6, 2026.
Read through reviews of airlines operating flights from St. Louis to Seattle, such as Southwest,Alaska Airlines, andDelta. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Entertainment
7.5
Crew
8.6
Boarding
8.1
Food
7.0
Overall
8.0
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentLibby,Jun 2026
TUS - LAS
Entertainment
7.5
Crew
8.6
Boarding
8.1
Food
7.0
Overall
8.0
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentLibby,Jun 2026
TUS - LAS
Entertainment
7.5
Crew
8.6
Boarding
8.1
Food
7.0
Overall
8.0
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentLibby,Jun 2026
TUS - LAS
Entertainment
7.5
Crew
8.6
Boarding
8.1
Food
7.0
Overall
8.0
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentLibby,Jun 2026
TUS - LAS
Entertainment
7.5
Crew
8.6
Boarding
8.1
Food
7.0
Overall
8.0
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentLibby,Jun 2026
TUS - LAS
Entertainment
7.5
Crew
8.6
Boarding
8.1
Food
7.0
Overall
8.0
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentLibby,Jun 2026
TUS - LAS
Related info for your journey
Find useful and relevant information for your journey from St. Louis to Seattle. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
Traveling to a place near Seattle?
Book flights to Seattle if you plan to visit one of these locationsSeaTac
Renton
Tacoma
Lacey
Leavenworth
Olympia
Tukwila
Edmonds
Snoqualmie
Tumwater
Centralia
Marysville
Puyallup
Kent
Ellensburg
Fife
Ocean Shores
Lakewood
Lynnwood
Poulsbo
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St. Louis and Seattle flights
Browse other St. Louis and Seattle flight options. Last updated on August 6, 2026.
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Top 7 airlines flying from St. Louis to Seattle
Discover the top 7 airlines that operate flights from St. Louis to Seattle. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated August 6, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$129 | Average$271 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$136 | Average$242 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$188 | Average$409 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$192 | Average$415 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$193 | Average$404 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$217 | Average$313 | FlexibilityNo cancel fee | On-time85% | |
| Cheapest$219 | Average$404 | FlexibilityNo cancel fee | On-time75% |