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$42+ Cheap flights from St. Louis (STL) to the United States

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 9/14. Fares are subject to change and may not be available on all flights or dates of travel.
STL — LAX
Aug 21 — Aug 281
Thu 8/21
Thu 8/28
1 adult, Economy
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Cheap flight deals from St. Louis to USA

Keep the following information in mind while searching for St. Louis to USA flight deals. Data was last updated August 16, 2025.

Round-trip from

$99
(Cheapflightsfares)

One-way from

$42
(Mytrip)

Popular in

November

Cheapest in

April

Average price

$328

Good round-trip deal

$70 or less

Good one-way deal

$79 or less
From Lambert-St Louis to USA
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One-way flight from Lambert-St Louis to USA
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Highest demand for flights based on searches. 10% potential increase in price ($36 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($6 potential savings vs. average RT price).
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Average for round-trip flights in August 2025
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Price to beat on a round-trip flight from Lambert-St Louis to USA.
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Price to beat on a one-way flight from Lambert-St Louis to USA.
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Find flight deals from St. Louis to USA

Cheapest flights from St. Louis to USA
Explore the most affordable flight options available from St. Louis to USA. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 16, 2025.

This Frontier deal was found by Cheapflights users on 8/15. 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.
Fri 9/267:55 pmSTL - DEN
Nonstop2h 25mFrontier
Wed 10/16:00 amDEN - STL
Nonstop2h 06mFrontier
Deal found 8/15$99
This Cheapflightsfares deal was found by Cheapflights users on 8/14. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/117:55 pmSTL - DEN
Nonstop2h 25mFrontier
Tue 9/166:00 amDEN - STL
Nonstop2h 06mFrontier
Deal found 8/14$101
This Frontier deal was found by Cheapflights users on 8/15. 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.
Tue 9/237:55 pmSTL - DEN
Nonstop2h 25mFrontier
Sun 9/286:00 amDEN - STL
Nonstop2h 06mFrontier
Deal found 8/15$103
This Cheapflightsfares deal was found by Cheapflights users on 8/15. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/57:55 pmSTL - DEN
Nonstop2h 25mFrontier
Sun 9/76:00 amDEN - STL
Nonstop2h 06mFrontier
Deal found 8/15$104
This Cheapflightsfares deal was found by Cheapflights users on 8/15. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/37:45 pmSTL - DEN
Nonstop2h 28mFrontier
Fri 11/76:00 amDEN - STL
Nonstop2h 07mFrontier
Deal found 8/15$105
This Frontier deal was found by Cheapflights users on 8/15. 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.
Thu 9/47:55 pmSTL - DEN
Nonstop2h 25mFrontier
Sun 9/76:00 amDEN - STL
Nonstop2h 06mFrontier
Deal found 8/15$106
This Frontier deal was found by Cheapflights users on 8/12. 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.
Fri 11/147:52 pmSTL - DEN
Nonstop2h 28mFrontier
Mon 11/176:00 amDEN - STL
Nonstop2h 07mFrontier
Deal found 8/12$107
This Frontier deal was found by Cheapflights users on 8/15. 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 9/177:55 pmSTL - DEN
Nonstop2h 25mFrontier
Sun 9/216:00 amDEN - STL
Nonstop2h 06mFrontier
Deal found 8/15$108
This Frontier deal was found by Cheapflights users on 8/14. 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.
Sat 9/137:55 pmSTL - DEN
Nonstop2h 25mFrontier
Sun 9/146:00 amDEN - STL
Nonstop2h 06mFrontier
Deal found 8/14$109
This Cheapflightsfares deal was found by Cheapflights users on 8/13. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/177:52 pmSTL - DEN
Nonstop2h 28mFrontier
Sun 10/196:00 amDEN - STL
Nonstop2h 07mFrontier
Deal found 8/13$110
This Cheapflightsfares deal was found by Cheapflights users on 8/15. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/127:55 pmSTL - DEN
Nonstop2h 25mFrontier
Sun 9/146:00 amDEN - STL
Nonstop2h 06mFrontier
Deal found 8/15$112
This Cheapflightsfares deal was found by Cheapflights users on 8/15. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/306:22 pmSTL - DEN
1 stop5h 50mFrontier
Sat 11/16:00 amDEN - STL
Nonstop2h 07mFrontier
Deal found 8/15$113

Cheapflights Fare Finder

 
Customize your flight search to find flights from St. Louis to USA 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 16, 2025.
Use the filters below to find and compare flights from St. Louis to the United States that are best for you.

Fly from

St. Louis

Fly to

USA

Route

Depart

Return

Price

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Fri 9/26

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Tue 9/30

6:00 am-9:06 am

Nonstop2h 06m

$99

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 9/3

7:54 pm-9:23 pm

Nonstop2h 29m

Denver Intl

Fri 9/5

6:00 am-9:06 am

Nonstop2h 06m

$99

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Fri 9/26

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Sat 9/27

6:00 am-9:06 am

Nonstop2h 06m

$99

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Fri 9/26

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Wed 10/1

6:00 am-9:06 am

Nonstop2h 06m

$99

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Thu 9/11

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Tue 9/16

6:00 am-9:06 am

Nonstop2h 06m

$101

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Fri 11/14

7:52 pm-9:20 pm

Nonstop2h 28m

Denver Intl

Tue 11/18

6:00 am-9:07 am

Nonstop2h 07m

$103

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sat 9/27

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Sun 9/28

6:00 am-9:06 am

Nonstop2h 06m

$103

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Tue 9/23

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Sun 9/28

6:00 am-9:06 am

Nonstop2h 06m

$103

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 9/24

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Sun 9/28

6:00 am-9:06 am

Nonstop2h 06m

$103

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sun 11/16

7:52 pm-9:20 pm

Nonstop2h 28m

Denver Intl

Tue 11/18

6:00 am-9:07 am

Nonstop2h 07m

$103

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/12

Showing 1-10 of 60 results
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Best time to book a flight from St. Louis to USA

Have a flexible travel schedule? Discover the best time to fly to USA from St. Louis 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.

Cheapflights Insights

Everything you need to know about your flight from St. Louis to the United States

What is the cheapest month to book a flight from St. Louis to USA?

Currently, January is the cheapest month in which you can book a flight from St. Louis to USA (average of $246). Flying from St. Louis to USA in March is currently the most expensive (average of $326). 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 US?

Find hourly flight availability from St. Louis to USA. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated August 16, 2025.

When flying from St. Louis to USA, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

Weekly flight availability from St. Louis to USA

Explore weekly flight availability from St. Louis to USA. 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 August 16, 2025.

The most flights from STL to US0 are scheduled on a Monday (10 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (6 on average).

Reviews of airlines servicing USA

Get insights into the airlines that provide service to USA. 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 USA. Reviews last updated August 16, 2025.
Peruse reviews from past customers who have flown with Southwest, Delta, and United Airlines from St. Louis to the United States to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,246 reviews

Boarding

8.1

Entertainment

7.5

Overall

8.0

Crew

8.6

Comfort

8.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Southwest
8.0
Very good
4,246 reviews
Southwest
8.0
Very good
4,246 reviews

Boarding

8.1

Entertainment

7.5

Overall

8.0

Crew

8.6

Comfort

8.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Delta
8.0
Very good
7,985 reviews
Southwest
8.0
Very good
4,246 reviews

Boarding

8.1

Entertainment

7.5

Overall

8.0

Crew

8.6

Comfort

8.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
United Airlines
7.4
Good
8,916 reviews
Southwest
8.0
Very good
4,246 reviews

Boarding

8.1

Entertainment

7.5

Overall

8.0

Crew

8.6

Comfort

8.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,246 reviews

Boarding

8.1

Entertainment

7.5

Overall

8.0

Crew

8.6

Comfort

8.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Frontier
5.8
Fair
3,211 reviews
Southwest
8.0
Very good
4,246 reviews

Boarding

8.1

Entertainment

7.5

Overall

8.0

Crew

8.6

Comfort

8.0

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.

Related info for your journey

Find useful and relevant information for your journey from St. Louis to USA. 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 St. Louis to United States?

    Lambert-St Louis (STL) is the airport you will fly out of if you book a flight from St. Louis to United States. It is only a 12.7 mi journey to Lambert-St Louis (STL) from St. Louis’s city center.

  • How popular is this St. Louis to USA flight route?

    Flights from Lambert-St Louis to United States have been viewed 12 times in the past calendar month.

  • What are the cheapest airlines to fly from St. Louis to USA one-way?

    To fly one-way, consider booking your trip with Frontier, which is currently one of the cheapest options available, starting at $42. Spirit Airlines flights start at $97 while deals on Delta start at $105 one-way.

  • What are the most popular routes from St. Louis to USA?

    The most popular flight routes from St. Louis to USA are Lambert-St Louis - Las Vegas Harry Reid Intl, Lambert-St Louis - Seattle/Tacoma Intl and Lambert-St Louis - Miami.

  • What are the most reliable airlines from St. Louis to USA?

    Before booking your flight to USA from St. Louis, check out the most reliable airlines to get you to your destination on time: SkyWest Airlines (84%), American Airlines (84%), Alaska Airlines( 84%).

  • What are the cheapest flights from St. Louis to USA?

    Looking for the cheapest flight from St. Louis to USA? While on average our users pay $679, our data indicates the cheapest price to be $158. The most popular route (Lambert-St Louis - Las Vegas Harry Reid Intl), is priced around $77.

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

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

  • How can I find direct flights from St. Louis to USA?

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

  • Can I find deals for business class flights from St. Louis to USA?

    Yes. Cheapflights offers flight deals from St. Louis to USA 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 St. Louis to USA?

    Currently, January is the cheapest month in which you can book a flight from St. Louis to USA (average of $246). Flying from St. Louis to USA in March is currently the most expensive (average of $326). 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.

See more FAQs

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Alternative routes for St. Louis to USA

See prices for flight routes from nearby airports that may be better suited for you.
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Top 9 airlines flying from St. Louis to USA

Discover the top 9 airlines that operate flights from St. Louis to USA. 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 16, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$46Average$197FlexibilityNo cancel feeOn-time62%
Spirit AirlinesCheapest$56Average$186FlexibilityNo cancel feeOn-time65%
Allegiant AirCheapest$104Average$238FlexibilityNo cancel feeOn-time88%
DeltaCheapest$128Average$353FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$153Average$408FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$177Average$403FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$186Average$373FlexibilityNo cancel feeOn-time71%
Southern / MokuleleCheapest$189Average$239FlexibilityNo cancel feeOn-timeN/A
Alaska AirlinesCheapest$296Average$476FlexibilityNo cancel feeOn-time75%

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