$151+ Cheap flights from Seattle (SEA) to St. Charles, MO
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 9/16. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — STL
Jul 26 — Aug 21
Round-trip
1 adult, Economy
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Find cheap flights from Seattle to St. Charles 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 Seattle/Tacoma Intl to St. Charles are usually found in January or February, booked 77 days in advance, depart on a Tuesday or Thursday and return on a Thursday
Cheap flight deals from Seattle to St. Charles
Cheapest
Best
Last-minute
One-way
Cheapest flights from Seattle to St. CharlesExplore the most affordable flight options available from Seattle to St. Charles. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 26, 2026.
Explore the most affordable flight options available from Seattle to St. Charles. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 26, 2026.
This Kiwi.com deal was found by Cheapflights users on 6/25. 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 7/161:06 pm
SEA
- STL
Nonstop3h 51m
Multiple Airlines
Sat 7/188:08 pm
STL
- SEA
1 stop15h 09m
Multiple Airlines
Deal found 6/25![Multiple Airlines logo]()
$376
This Delta deal was found by Cheapflights users on 6/22. 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 10/711:05 pm
SEA
- STL
1 stop8h 31m
Delta
Sat 10/107:55 pm
STL
- SEA
1 stop6h 16m
Delta
Deal found 6/22![Delta logo]()
$377
This Kiwi.com deal was found by Cheapflights users on 6/23. 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 10/86:00 pm
SEA
- STL
Nonstop3h 59m
Multiple Airlines
Sat 10/178:10 pm
STL
- SEA
1 stop15h 41m
Multiple Airlines
Deal found 6/23![Multiple Airlines logo]()
$378
This United Airlines deal was found by Cheapflights users on 6/22. 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.
Thu 10/812:00 pm
SEA
- STL
1 stop8h 30m
United Airlines
Fri 10/98:00 am
STL
- SEA
1 stop10h 06m
United Airlines
Deal found 6/22![United Airlines logo]()
$379
This KAYAK deal was found by Cheapflights users on 6/23. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/31:59 pm
SEA
- STL
1 stop6h 30m
American Airlines
Thu 11/57:00 am
STL
- SEA
1 stop9h 59m
American Airlines
Deal found 6/23![American Airlines logo]()
$380
This Booking.com deal was found by Cheapflights users on 6/22. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/138:53 pm
SEA
- STL
1 stop19h 12m
Multiple Airlines
Thu 7/166:02 am
STL
- SEA
Nonstop4h 28m
Multiple Airlines
Deal found 6/22![Multiple Airlines logo]()
$381
This Southwest deal was found by Cheapflights users on 6/24. 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.
Tue 10/1312:15 am
SEA
- STL
1 stop6h 45m
Southwest
Sat 10/176:35 am
STL
- SEA
2 stops9h 55m
Southwest
Deal found 6/24![Southwest logo]()
$382
This Kiwi.com deal was found by Cheapflights users on 6/21. 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.
Tue 7/216:04 pm
SEA
- STL
Nonstop3h 55m
Multiple Airlines
Tue 7/288:08 pm
STL
- SEA
1 stop15h 09m
Multiple Airlines
Deal found 6/21![Multiple Airlines logo]()
$383
This United Airlines deal was found by Cheapflights users on 6/23. 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 8/257:11 am
SEA
- STL
2 stops11h 35m
United Airlines
Sun 8/305:10 am
STL
- SEA
1 stop6h 51m
United Airlines
Deal found 6/23![United Airlines logo]()
$384
This Kiwi.com deal was found by Cheapflights users on 6/24. 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 7/226:04 pm
SEA
- STL
Nonstop3h 55m
Multiple Airlines
Sat 7/258:08 pm
STL
- SEA
1 stop15h 09m
Multiple Airlines
Deal found 6/24![Multiple Airlines logo]()
$385
This Kiwi.com deal was found by Cheapflights users on 6/23. 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 8/66:04 pm
SEA
- STL
Nonstop3h 55m
Multiple Airlines
Sun 8/98:08 pm
STL
- SEA
1 stop14h 56m
Multiple Airlines
Deal found 6/23![Multiple Airlines logo]()
$386
This Southwest deal was found by Cheapflights users on 6/25. 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.
Tue 8/251:45 pm
SEA
- STL
1 stop6h 50m
Southwest
Sun 8/3010:55 am
STL
- SEA
Nonstop4h 20m
Southwest
Deal found 6/25![Southwest logo]()
$387
Best flights from Seattle to St. CharlesDiscover carefully curated flight deals from Seattle to St. Charles that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated June 26, 2026.
Discover carefully curated flight deals from Seattle to St. Charles that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated June 26, 2026.
This United Airlines deal was found by Cheapflights users on 6/21. 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.
Mon 8/311:11 pm
SEA
- STL
1 stop7h 28m
United Airlines
Mon 8/101:13 pm
STL
- SEA
1 stop7h 53m
United Airlines
Deal found 6/21![United Airlines logo]()
$379
This Southwest deal was found by Cheapflights users on 6/22. 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 7/295:15 am
SEA
- STL
1 stop6h 15m
Southwest
Wed 7/296:40 pm
STL
- SEA
1 stop6h 55m
Southwest
Deal found 6/22![Southwest logo]()
$387
This Alaska Airlines deal was found by Cheapflights users on 6/22. 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.
Fri 7/247:55 am
SEA
- STL
Nonstop3h 57m
Alaska Airlines
Tue 7/287:56 pm
STL
- SEA
Nonstop4h 28m
Alaska Airlines
Deal found 6/22![Alaska Airlines logo]()
$482
This Delta deal was found by Cheapflights users on 6/23. 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.
Thu 9/1011:05 pm
SEA
- STL
1 stop8h 24m
Delta
Sun 9/136:15 am
STL
- SEA
2 stops8h 22m
Delta
Deal found 6/23![Delta logo]()
$585
This United Airlines deal was found by Cheapflights users on 6/24. 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 9/207:00 am
SEA
- STL
1 stop6h 38m
United Airlines
Sat 9/269:00 am
STL
- SEA
2 stops14h 01m
United Airlines
Deal found 6/24![United Airlines logo]()
$384
This Southwest deal was found by Cheapflights users on 6/24. 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 7/227:30 am
SEA
- STL
2 stops9h 10m
Southwest
Sat 7/254:40 pm
STL
- SEA
2 stops9h 35m
Southwest
Deal found 6/24![Southwest logo]()
$397
This United Airlines deal was found by Cheapflights users on 6/23. 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 9/2211:03 am
SEA
- STL
2 stops8h 57m
United Airlines
Wed 9/231:36 pm
STL
- SEA
2 stops9h 07m
United Airlines
Deal found 6/23![United Airlines logo]()
$389
This United Airlines deal was found by Cheapflights users on 6/25. 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.
Fri 7/1011:49 pm
SEA
- STL
1 stop8h 18m
United Airlines
Tue 7/147:23 pm
STL
- SEA
1 stop7h 50m
United Airlines
Deal found 6/25![United Airlines logo]()
$393
This Alaska Airlines deal was found by Cheapflights users on 6/21. 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.
Thu 8/139:28 pm
SEA
- STL
2 stops8h 56m
Alaska Airlines
Wed 8/1910:16 am
STL
- SEA
2 stops11h 36m
Alaska Airlines
Deal found 6/21![Alaska Airlines logo]()
$542
This Alaska Airlines deal was found by Cheapflights users on 6/21. 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.
Thu 7/166:04 pm
SEA
- STL
Nonstop3h 55m
Alaska Airlines
Sun 7/197:56 pm
STL
- SEA
Nonstop4h 28m
Alaska Airlines
Deal found 6/21![Alaska Airlines logo]()
$543
This United Airlines deal was found by Cheapflights users on 6/25. 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.
Thu 8/2712:22 pm
SEA
- STL
2 stops9h 18m
United Airlines
Mon 8/311:36 pm
STL
- SEA
2 stops11h 50m
United Airlines
Deal found 6/25![United Airlines logo]()
$489
This Alaska Airlines deal was found by Cheapflights users on 6/22. 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.
Fri 7/246:04 pm
SEA
- STL
Nonstop3h 55m
Alaska Airlines
Thu 7/307:56 pm
STL
- SEA
Nonstop4h 28m
Alaska Airlines
Deal found 6/22![Alaska Airlines logo]()
$567
Last-minute flights from Seattle to St. CharlesDiscover last-minute flight deals from Seattle to St. Charles. Data last updated June 26, 2026 and is based on user searches.
Discover last-minute flight deals from Seattle to St. Charles. Data last updated June 26, 2026 and is based on user searches.
This Trip.com deal was found by Cheapflights users on 6/24. 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.
Mon 6/298:12 pm
SEA
- STL
1 stop20h 39m
Frontier
Mon 7/68:08 pm
STL
- SEA
1 stop15h 09m
Frontier
Deal found 6/24![Frontier logo]()
$388
This Alaska Airlines deal was found by Cheapflights users on 6/22. 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 7/86:04 pm
SEA
- STL
Nonstop3h 55m
Alaska Airlines
Tue 7/217:56 pm
STL
- SEA
Nonstop4h 28m
Alaska Airlines
Deal found 6/22![Alaska Airlines logo]()
$387
This Alaska Airlines deal was found by Cheapflights users on 6/23. 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.
Fri 7/106:04 pm
SEA
- STL
Nonstop3h 55m
Alaska Airlines
Sun 7/127:56 pm
STL
- SEA
Nonstop4h 28m
Alaska Airlines
Deal found 6/23![Alaska Airlines logo]()
$377
This Booking.com deal was found by Cheapflights users on 6/22. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/138:53 pm
SEA
- STL
1 stop19h 12m
Multiple Airlines
Thu 7/166:02 am
STL
- SEA
Nonstop4h 28m
Multiple Airlines
Deal found 6/22![Multiple Airlines logo]()
$381
This Kiwi.com deal was found by Cheapflights users on 6/22. 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 7/138:53 pm
SEA
- STL
2 stops18h 44m
Frontier
Thu 7/167:10 pm
STL
- SEA
1 stop17h 29m
Frontier
Deal found 6/22![Frontier logo]()
$384
This Kiwi.com deal was found by Cheapflights users on 6/25. 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 7/161:06 pm
SEA
- STL
Nonstop3h 51m
Multiple Airlines
Sat 7/188:08 pm
STL
- SEA
1 stop15h 09m
Multiple Airlines
Deal found 6/25![Multiple Airlines logo]()
$376
This Kiwi.com deal was found by Cheapflights users on 6/21. 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.
Tue 7/216:04 pm
SEA
- STL
Nonstop3h 55m
Multiple Airlines
Tue 7/288:08 pm
STL
- SEA
1 stop15h 09m
Multiple Airlines
Deal found 6/21![Multiple Airlines logo]()
$383
This American Airlines deal was found by Cheapflights users on 6/22. 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.
Wed 7/223:28 pm
SEA
- STL
1 stop6h 48m
American Airlines
Tue 7/282:46 pm
STL
- SEA
1 stop8h 19m
American Airlines
Deal found 6/22![American Airlines logo]()
$379
This Kiwi.com deal was found by Cheapflights users on 6/24. 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 7/226:04 pm
SEA
- STL
Nonstop3h 55m
Multiple Airlines
Sat 7/258:08 pm
STL
- SEA
1 stop15h 09m
Multiple Airlines
Deal found 6/24![Multiple Airlines logo]()
$385
This Kiwi.com deal was found by Cheapflights users on 6/23. 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.
Tue 7/287:06 pm
SEA
- STL
2 stops11h 51m
Frontier
Fri 7/317:10 pm
STL
- SEA
1 stop17h 29m
Frontier
Deal found 6/23![Frontier logo]()
$380
This Kiwi.com deal was found by Cheapflights users on 6/23. 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.
Tue 7/287:55 am
SEA
- STL
Nonstop3h 57m
Multiple Airlines
Fri 7/317:10 pm
STL
- SEA
1 stop17h 29m
Multiple Airlines
Deal found 6/23![Multiple Airlines logo]()
$389
One-way flights from Seattle to St. CharlesSearch for one-way flight options from Seattle to St. Charles. Find affordable one-way fares based on user searches. Data last updated June 26, 2026.
Search for one-way flight options from Seattle to St. Charles. Find affordable one-way fares based on user searches. Data last updated June 26, 2026.
This Frontier deal was found by Cheapflights users on 6/21. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/169:16 pm
SEA
- STL
1 stop12h 35m
Frontier
Deal found 6/21![Frontier logo]()
$151
This Kiwi.com deal was found by Cheapflights users on 6/22. 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.
Tue 8/188:53 pm
SEA
- STL
1 stop18h 57m
Frontier
Deal found 6/22![Frontier logo]()
$156
This Super.com deal was found by Cheapflights users on 6/25. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 7/127:06 pm
SEA
- STL
1 stop22h 17m
Frontier
Deal found 6/25![Frontier logo]()
$160
This Super.com deal was found by Cheapflights users on 6/22. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/308:53 pm
SEA
- STL
1 stop19h 22m
Frontier
Deal found 6/22![Frontier logo]()
$161
This Expedia deal was found by Cheapflights users on 6/22. 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.
Sun 9/207:41 pm
SEA
- STL
1 stop21h 34m
Frontier
Deal found 6/22![Frontier logo]()
$163
This Kiwi.com deal was found by Cheapflights users on 6/24. 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 7/207:06 pm
SEA
- STL
1 stop22h 17m
Frontier
Deal found 6/24![Frontier logo]()
$164
This Kiwi.com deal was found by Cheapflights users on 6/22. 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.
Tue 7/217:06 pm
SEA
- STL
1 stop22h 17m
Frontier
Deal found 6/22![Frontier logo]()
$166
This CheapOair deal was found by Cheapflights users on 6/21. 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.
Sat 8/88:13 pm
SEA
- STL
1 stop20h 02m
Frontier
Deal found 6/21![Frontier logo]()
$168
This Kiwi.com deal was found by Cheapflights users on 6/24. 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 8/197:06 pm
SEA
- STL
2 stops20h 16m
Frontier
Deal found 6/24![Frontier logo]()
$172
This Kiwi.com deal was found by Cheapflights users on 6/24. 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 8/227:06 pm
SEA
- STL
2 stops20h 16m
Frontier
Deal found 6/24![Frontier logo]()
$174
Find flight deals from Seattle to St. Charles
Keep the following information in mind while searching for Seattle to St. Charles flight deals. Data was last updated June 26, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $376 (Kiwi.com) |
One-way from | $151 (Frontier) |
Popular in | December |
Cheapest in | January |
Average price | $491 |
Cheapflights Fare Finder
Customize your flight search to find flights from Seattle to St. Charles 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 June 26, 2026.
Use the filters below to find and compare flights from Seattle to St. Charles that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
SeattleSt. Louis
SEA - STL
SEASTL
Seattle/Tacoma Intl
Mon 8/3
11:11 pm-8:39 am
1 stop7h 28m
Lambert-St Louis
Mon 8/10
1:13 pm-7:06 pm
1 stop7h 53m
$379
SeattleSt. Louis
SEA - STL
SEASTL
Seattle/Tacoma Intl
Sun 9/20
7:00 am-3:38 pm
1 stop6h 38m
Lambert-St Louis
Sat 9/26
9:00 am-9:01 pm
2 stops14h 01m
$384
SeattleSt. Louis
SEA - STL
SEASTL
Seattle/Tacoma Intl
Wed 7/29
5:15 am-1:30 pm
1 stop6h 15m
Lambert-St Louis
Wed 7/29
6:40 pm-11:35 pm
1 stop6h 55m
$387
SeattleSt. Louis
SEA - STL
SEASTL
Seattle/Tacoma Intl
Tue 9/22
11:03 am-10:00 pm
2 stops8h 57m
Lambert-St Louis
Wed 9/23
1:36 pm-8:43 pm
2 stops9h 07m
$389
SeattleSt. Louis
SEA - STL
SEASTL
Seattle/Tacoma Intl
Fri 7/10
11:49 pm-10:07 am
1 stop8h 18m
Lambert-St Louis
Tue 7/14
7:23 pm-1:13 am
1 stop7h 50m
$393
SeattleSt. Louis
SEA - STL
SEASTL
Seattle/Tacoma Intl
Wed 7/22
7:30 am-6:40 pm
2 stops9h 10m
Lambert-St Louis
Sat 7/25
4:40 pm-12:15 am
2 stops9h 35m
$397
SeattleSt. Louis
SEA - STL
SEASTL
Seattle/Tacoma Intl
Fri 7/24
7:55 am-1:52 pm
Nonstop3h 57m
Lambert-St Louis
Tue 7/28
7:56 pm-10:24 pm
Nonstop4h 28m
$482
SeattleSt. Louis
SEA - STL
SEASTL
Seattle/Tacoma Intl
Thu 8/27
12:22 pm-11:40 pm
2 stops9h 18m
Lambert-St Louis
Mon 8/31
1:36 pm-11:26 pm
2 stops11h 50m
$489
SeattleSt. Louis
SEA - STL
SEASTL
Seattle/Tacoma Intl
Thu 8/13
9:28 pm-8:24 am
2 stops8h 56m
Lambert-St Louis
Wed 8/19
10:16 am-7:52 pm
2 stops11h 36m
$542
Quickest round-trip
SeattleSt. Louis
SEA - STL
SEASTL
Seattle/Tacoma Intl
Thu 7/16
6:04 pm-11:59 pm
Nonstop3h 55m
Lambert-St Louis
Sun 7/19
7:56 pm-10:24 pm
Nonstop4h 28m
$543
Showing 1-10 of 24 resultsSorted by cheapest first
Best time to book a flight from Seattle to St. Charles
Have a flexible travel schedule? Discover the best time to fly to St. Charles from Seattle with our price prediction graph.
SEA-STL
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 Seattle to St. Charles
SEA-CH5
SEA-STL
What is the cheapest time of day to fly from SEA to CH5?
Find hourly flight availability from Seattle to St. Charles. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 26, 2026.
Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Seattle to St. Charles as you normally would.
Weekly flight availability from Seattle to St. Charles
Explore weekly flight availability from Seattle to St. Charles. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated June 26, 2026.
The most flights from SEA to CH5 are scheduled on a Thursday (10 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (5 on average).
How much does it cost to fly round-trip from Seattle to St. Charles?
Reviews of airlines servicing St. Charles
Get insights into the airlines that provide service to St. Charles. 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 St. Charles. Reviews last updated June 26, 2026.
Get a feel of what it's like to fly with Alaska Airlines,Southwest, andDelta from Seattle to St. Charles by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Crew
8.5
Boarding
8.1
Entertainment
7.0
Food
7.0
Comfort
7.8
Overall
7.9
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Crew
8.5
Boarding
8.1
Entertainment
7.0
Food
7.0
Comfort
7.8
Overall
7.9
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Crew
8.5
Boarding
8.1
Entertainment
7.0
Food
7.0
Comfort
7.8
Overall
7.9
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Crew
8.5
Boarding
8.1
Entertainment
7.0
Food
7.0
Comfort
7.8
Overall
7.9
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Crew
8.5
Boarding
8.1
Entertainment
7.0
Food
7.0
Comfort
7.8
Overall
7.9
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Crew
8.5
Boarding
8.1
Entertainment
7.0
Food
7.0
Comfort
7.8
Overall
7.9
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Related info for your journey
Find useful and relevant information for your journey from Seattle to St. Charles. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
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Alternative routes for Seattle to St. Charles
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Complete your trip
Complete your trip to St. Charles by adding a car rental and/or hotel reservation to your travel itinerary.
Search flights from Seattle to St. Charles by cabin class
Find flights from Seattle to St. Charles, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Seattle and St. Charles flights
Browse other Seattle and St. Charles flight options. Last updated on June 26, 2026.
Other flights from Seattle
Browse through other flights departing from Seattle. Flights are based on user searches made on Cheapflights and were last updated on June 26, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Seattle to St. Charles flights
Consider these flights traveling from Seattle to St. Charles.
Top 7 airlines flying from Seattle to St. Charles
Discover the top 7 airlines that operate flights from Seattle to St. Charles. 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 June 26, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$104 | Average$317 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$137 | Average$227 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$157 | Average$431 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$182 | Average$377 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$188 | Average$555 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$204 | Average$403 | FlexibilityNo cancel fee | On-time85% | |
| Cheapest$226 | Average$427 | FlexibilityNo cancel fee | On-time75% |