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St. Charles

$64+ 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 3/13. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — STL
Feb 4 — Feb 111
Tue 2/4
Tue 2/11
1 adult, Economy
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The best prices from Seattle/Tacoma Intl to St. Charles are usually found in January or February, booked 73 days in advance, depart on a Thursday or Saturday and return on a Thursday

Cheap flight deals from Seattle to St. Charles

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to St. Charles (CH5). 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 January 30, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$247
(Alaska Airlines)

One-way from

$64
(Trip.com)

Popular in

December

Cheapest in

January

Average price

$296
Provider with most accurate pricing for Seattle/Tacoma Intl-Lambert-St Louis flight deals.
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Provider most trusted by Cheapflights users for Seattle/Tacoma Intl-Lambert-St Louis flights.
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From Seattle/Tacoma Intl to St. Charles
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One-way flight from Seattle/Tacoma Intl to St. Charles
Search Deals
Highest demand for flights based on searches. 5% potential increase in price ($22 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($10 potential savings vs. average RT price).
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Average for round-trip flights in January 2025
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Find flight deals from Seattle to St. Charles

Cheapest flights from Seattle to St. Charles
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 January 30, 2025.

This Alaska Airlines deal was found by Cheapflights users on 1/29. 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 2/266:11 pmSEA - STL
Nonstop3h 48mAlaska Airlines
Sun 3/27:00 amSTL - SEA
Nonstop4h 35mAlaska Airlines
Deal found 1/29$247
This Booking.com deal was found by Cheapflights users on 1/29. 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.
Thu 2/132:02 pmSEA - STL
1 stop17h 14mFrontier
Fri 2/2111:08 pmSTL - SEA
1 stop12h 22mFrontier
Deal found 1/29$250
This Southwest deal was found by Cheapflights users on 1/29. 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 2/2610:40 amSEA - STL
1 stop9h 25mSouthwest
Tue 3/411:15 amSTL - SEA
2 stops8h 35mSouthwest
Deal found 1/29$252
This United Airlines deal was found by Cheapflights users on 1/29. 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.
Wed 2/198:50 amSEA - STL
1 stop5h 43mUnited Airlines
Thu 2/206:30 amSTL - SEA
2 stops11h 24mUnited Airlines
Deal found 1/29$256
This Delta deal was found by Cheapflights users on 1/29. 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 2/136:15 amSEA - STL
1 stop8h 38mDelta
Tue 2/185:00 pmSTL - SEA
1 stop9h 50mDelta
Deal found 1/29$258
This Orbitz deal was found by Cheapflights users on 1/29. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 2/136:11 pmSEA - STL
Nonstop3h 48mMultiple Airlines
Fri 2/2111:08 pmSTL - SEA
1 stop12h 22mMultiple Airlines
Deal found 1/29$289
This American Airlines deal was found by Cheapflights users on 1/29. 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.
Mon 3/108:26 amSEA - STL
Nonstop3h 59mAmerican Airlines
Wed 3/125:37 pmSTL - SEA
1 stop9h 11mAmerican Airlines
Deal found 1/29$297

Find flights from Seattle to St. Charles within your budget

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 January 30, 2025.

Fly from

Any airport

Fly to

Any airport

Route

Depart

Return

Price

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Wed 2/26

6:11 pm-11:59 pm

Nonstop3h 48m

Lambert-St Louis

Mon 3/3

7:00 am-9:35 am

Nonstop4h 35m

$247

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Thu 2/13

2:02 pm-9:16 am

1 stop17h 14m

Lambert-St Louis

Fri 2/21

11:08 pm-9:30 am

1 stop12h 22m

$250

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Wed 2/26

10:40 am-10:05 pm

1 stop9h 25m

Lambert-St Louis

Tue 3/4

11:15 am-5:50 pm

2 stops8h 35m

$252

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Sat 3/1

9:20 am-8:44 pm

2 stops9h 24m

Lambert-St Louis

Thu 3/6

7:00 am-1:43 pm

1 stop8h 43m

$255

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Thu 2/13

6:15 am-4:53 pm

1 stop8h 38m

Lambert-St Louis

Tue 2/18

5:00 pm-12:50 am

1 stop9h 50m

$258

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Thu 2/13

6:11 pm-11:59 pm

Nonstop3h 48m

Lambert-St Louis

Fri 2/21

11:08 pm-9:30 am

1 stop12h 22m

$289

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Mon 3/10

8:26 am-2:25 pm

Nonstop3h 59m

Lambert-St Louis

Wed 3/12

5:37 pm-12:48 am

1 stop9h 11m

$297

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Thu 3/13

2:02 pm-9:16 am

1 stop17h 14m

$64

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Mon 4/28

12:59 am-10:33 am

1 stop7h 34m

$79

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Tue 2/25

11:05 pm-9:36 am

1 stop8h 31m

$109

Flights are sorted by cheapest round-trip flights first.

Deals found on 1/29

Showing 1-10 of 14 results
1
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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.
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.

Travel insights for flights from Seattle to St. Charles

Get recent, data-driven insights about flights from Seattle to St. Charles including ideal travel times, pricing trends, and more.

How far ahead should I book a flight from Seattle to St. Charles?

Use this chart to determine the optimal time to book a round-trip flight from Seattle to St. Charles. Price data was last updated on January 24, 2025.

The best time to book flights from Seattle to St. Charles is 73 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 Seattle to St. Charles?

Currently, August is the cheapest month in which you can book a flight from Seattle to St. Charles (average of $311). Flying from Seattle to St. Charles in March is currently the most expensive (average of $356). 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 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 January 30, 2025.

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.

What is the cheapest day to fly from Seattle to St. Charles?

Use this chart to determine the cheapest time to fly round-trip from Seattle to St. Charles. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their Seattle to St. Charles flight should consider departing on Tuesday evenings 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.

Rainfall in St. Charles by month

Plan your trip to St. Charles by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in St. Charles ranges from 2.2 - 4.7 inches per month. May is typically the wettest month, when rainfall can reach 4.7 in. February is typically the driest time to visit St. Charles when rainfall is around 2.2 in.

Temperature in St. Charles by month

Plan your trip to St. Charles by taking into account the average temperature totals by month.

If weather is an important factor for your trip to St. Charles, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 80.6 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 32.0 F).

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 January 30, 2025.
Read through reviews of airlines operating flights from Seattle to St. Charles, such as Southwest, Alaska Airlines and Delta. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.1
Very good
4,585 reviews

Overall

8.1

Crew

8.7

Boarding

8.2

Entertainment

7.7

Food

7.1

Comfort

8.1

Reviews

1 / 20

6.0
Good

Lauren,Dec 2024

MCI - DCA

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Southwest
8.1
Very good
4,585 reviews
Southwest
8.1
Very good
4,585 reviews

Overall

8.1

Crew

8.7

Boarding

8.2

Entertainment

7.7

Food

7.1

Comfort

8.1

Reviews

1 / 20

6.0
Good

Lauren,Dec 2024

MCI - DCA

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Alaska Airlines
8.0
Very good
9,688 reviews
Southwest
8.1
Very good
4,585 reviews

Overall

8.1

Crew

8.7

Boarding

8.2

Entertainment

7.7

Food

7.1

Comfort

8.1

Reviews

1 / 20

6.0
Good

Lauren,Dec 2024

MCI - DCA

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Delta
8.0
Very good
8,454 reviews
Southwest
8.1
Very good
4,585 reviews

Overall

8.1

Crew

8.7

Boarding

8.2

Entertainment

7.7

Food

7.1

Comfort

8.1

Reviews

1 / 20

6.0
Good

Lauren,Dec 2024

MCI - DCA

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

United Airlines
7.4
Good
8,913 reviews
Southwest
8.1
Very good
4,585 reviews

Overall

8.1

Crew

8.7

Boarding

8.2

Entertainment

7.7

Food

7.1

Comfort

8.1

Reviews

1 / 20

6.0
Good

Lauren,Dec 2024

MCI - DCA

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

American Airlines
7.2
Good
10,000 reviews
Southwest
8.1
Very good
4,585 reviews

Overall

8.1

Crew

8.7

Boarding

8.2

Entertainment

7.7

Food

7.1

Comfort

8.1

Reviews

1 / 20

6.0
Good

Lauren,Dec 2024

MCI - DCA

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

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.

  • What airport do you fly from for flights from Seattle to St. Charles?

    If you book a flight to St. Charles from Seattle, you will be flying from Seattle/Tacoma Intl, which is the city’s only airport. Seattle/Tacoma Intl (SEA) is located 11.4 mi from the center of Seattle. There is 1 flight from Seattle/Tacoma Intl to St. Charles per day from 6 different airlines.

  • How popular is this Seattle to St. Charles flight route?

    This flight path from Seattle/Tacoma Intl to St. Charles was viewed by 5 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

  • What are the cheapest airlines to fly from Seattle to St. Charles one-way?

    To fly one-way, consider booking your trip with Frontier, which is currently one of the cheapest options available, starting at $64. American Airlines flights start at $79 while deals on Delta start at $109 one-way.

  • What are the most reliable airlines from Seattle to St. Charles?

    The top 3 most reliable airlines when flying from Seattle to St. Charles are Hawaiian Airlines (86%), American Airlines (86%) and Singapore Airlines (86%).

  • What are the cheapest flights from Seattle to St. Charles?

    On average you can expect to pay $360 for a flight from Seattle to St. Charles. The cheapest flight overall is $148 while the most popular route, (Seattle/Tacoma Intl - Lambert-St Louis) is currently priced at $184.

  • Can I find deals for flights from Seattle to St. Charles that include hotel bookings?

    Yes. In addition to deals on Seattle to St. Charles flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Seattle to St. Charles?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to St. Charles.

  • Can I find deals for business class flights from Seattle to St. Charles?

    Yes. Cheapflights offers flight deals from Seattle to St. Charles by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Seattle to St. Charles?

    Currently, August is the cheapest month in which you can book a flight from Seattle to St. Charles (average of $311). Flying from Seattle to St. Charles in March is currently the most expensive (average of $356). 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.

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Alternative routes for Seattle to St. Charles

See prices for flight routes from nearby airports that may be better suited for you.
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Top 6 airlines flying from Seattle to St. Charles

Discover the top 6 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 January 30, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$141Average$233FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$196Average$565FlexibilityNo cancel feeOn-time71%
DeltaCheapest$200Average$306FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$216Average$354FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$235Average$411FlexibilityNo cancel feeOn-time75%
SouthwestCheapest$375Average$529FlexibilityNo cancel feeOn-time63%
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