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St. Louis

$42+ Cheap flights from Denver to St. Louis (DEN - STL)

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 10/16. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — STL
Oct 19 — Oct 261
Sun 10/19
Sun 10/26
1 adult, Economy
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Cheapflights Tip: The best prices from Denver Intl to Lambert-St Louis are usually found in January or October, booked 74 days in advance, depart on a Friday or Wednesday and return on a Wednesday

Cheap flight deals from Denver to St. Louis

Discover tips and strategies to find the most affordable flight options for your journey from Denver (DEN) to St. Louis (STL). 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 September 19, 2025.

Round-trip from

$98
(Cheapflightsfares)

One-way from

$42
(Kiwi.com)

Popular in

June

Cheapest in

January

Average price

$237

Good round-trip deal

$165 or less

Good one-way deal

$109 or less
From Denver Intl to Lambert-St Louis
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One-way flight from Denver Intl to Lambert-St Louis
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Highest demand for flights based on searches. 12% potential increase in price ($32 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease ($7 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Price to beat on a round-trip flight from Denver Intl to Lambert-St Louis.
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Price to beat on a one-way flight from Denver Intl to Lambert-St Louis.
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Find flight deals from Denver to St. Louis

Cheapest flights from Denver to St. Louis
Explore the most affordable flight options available from Denver to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 19, 2025.

This Priceline deal was found by Cheapflights users on 9/18. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/266:00 amDEN - STL
Nonstop2h 06mFrontier
Tue 9/307:55 pmSTL - DEN
Nonstop2h 25mFrontier
Deal found 9/18$98
This Frontier deal was found by Cheapflights users on 9/18. 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 10/226:00 amDEN - STL
Nonstop2h 07mFrontier
Fri 10/247:52 pmSTL - DEN
Nonstop2h 28mFrontier
Deal found 9/18$99
This Kiwi.com deal was found by Cheapflights users on 9/18. 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 10/256:00 amDEN - STL
Nonstop2h 07mFrontier
Mon 10/278:21 pmSTL - DEN
1 stop15h 08mFrontier
Deal found 9/18$100
This Cheapflightsfares deal was found by Cheapflights users on 9/16. 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 9/266:00 amDEN - STL
Nonstop2h 06mFrontier
Fri 9/267:55 pmSTL - DEN
Nonstop2h 25mFrontier
Deal found 9/16$101
This Kiwi.com deal was found by Cheapflights users on 9/17. 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 9/276:00 amDEN - STL
Nonstop2h 06mFrontier
Tue 9/307:55 pmSTL - DEN
Nonstop2h 25mFrontier
Deal found 9/17$102
This Priceline deal was found by Cheapflights users on 9/17. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/126:00 amDEN - STL
Nonstop2h 07mFrontier
Fri 11/147:45 pmSTL - DEN
Nonstop2h 28mFrontier
Deal found 9/17$105
This Frontier deal was found by Cheapflights users on 9/17. 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 11/86:00 amDEN - STL
Nonstop2h 07mFrontier
Sat 11/154:51 pmSTL - DEN
1 stop12h 08mFrontier
Deal found 9/17$106
This Frontier deal was found by Cheapflights users on 9/18. 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 10/146:00 amDEN - STL
Nonstop2h 07mFrontier
Wed 10/157:52 pmSTL - DEN
Nonstop2h 28mFrontier
Deal found 9/18$108
This Frontier deal was found by Cheapflights users on 9/18. 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 9/266:00 amDEN - STL
Nonstop2h 06mFrontier
Sat 9/277:55 pmSTL - DEN
Nonstop2h 25mFrontier
Deal found 9/18$109
This Cheapflightsfares deal was found by Cheapflights users on 9/17. 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 12/56:50 amDEN - STL
Nonstop2h 12mFrontier
Mon 12/87:43 pmSTL - DEN
Nonstop2h 32mFrontier
Deal found 9/17$110
This Cheapflightsfares deal was found by Cheapflights users on 9/17. 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 10/176:00 amDEN - STL
Nonstop2h 07mFrontier
Fri 10/2411:11 amSTL - DEN
1 stop11h 15mFrontier
Deal found 9/17$115
This Priceline deal was found by Cheapflights users on 9/17. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/2912:59 amDEN - STL
1 stop8h 13mFrontier
Sun 11/27:45 pmSTL - DEN
Nonstop2h 28mFrontier
Deal found 9/17$116

Cheapflights Fare Finder

 
Customize your flight search to find flights from Denver to St. Louis 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 September 19, 2025.
Use the filters below to find and compare flights from Denver to St. Louis that are best for you.

Fly from

Denver

Fly to

St. Louis

Route

Depart

Return

Price

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Wed 10/15

6:00 am-9:07 am

Nonstop2h 07m

Lambert-St Louis

Wed 10/22

7:52 pm-9:20 pm

Nonstop2h 28m

$109

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Sat 10/18

6:00 am-9:07 am

Nonstop2h 07m

Lambert-St Louis

Fri 10/24

11:11 am-9:26 pm

1 stop11h 15m

$117

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Thu 10/30

6:00 am-9:07 am

Nonstop2h 07m

Lambert-St Louis

Sun 11/2

7:45 pm-9:13 pm

Nonstop2h 28m

$118

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Fri 10/3

6:00 am-9:06 am

Nonstop2h 06m

Lambert-St Louis

Sat 10/4

7:55 pm-9:20 pm

Nonstop2h 25m

$125

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Wed 10/1

6:00 am-9:06 am

Nonstop2h 06m

Lambert-St Louis

Sat 10/4

7:55 pm-9:20 pm

Nonstop2h 25m

$134

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Sat 10/4

6:00 am-9:06 am

Nonstop2h 06m

Lambert-St Louis

Sun 10/5

1:57 pm-8:09 am

1 stop19h 12m

$139

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Mon 10/6

6:00 am-9:06 am

Nonstop2h 06m

Lambert-St Louis

Fri 10/10

9:59 pm-3:59 am

1 stop7h 00m

$149

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Sat 11/8

9:30 am-5:00 pm

2 stops6h 30m

Lambert-St Louis

Sat 11/15

10:25 am-11:45 am

Nonstop2h 20m

$172

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Tue 10/14

6:00 am-11:45 am

1 stop4h 45m

Lambert-St Louis

Wed 10/15

12:45 pm-5:00 pm

1 stop5h 15m

$177

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Thu 11/6

9:40 am-2:30 pm

1 stop3h 50m

Lambert-St Louis

Sat 11/8

12:20 pm-5:45 pm

2 stops6h 25m

$182

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/18

Showing 1-10 of 20 results
1
2

The best insider tips for Denver to St. Louis flights

Snippets provided in this section are AI-generated based on a summarization of Cheapflights-commissioned articles. The articles are presented as-is, for general informational purposes only, and may not be up-to-date. The opinions contained in the articles are original to the author and reflect their authentic experience, which may vary significantly from the experience of others.
Cheapflights partnered with top experts to bring you the best recommendations for your Denver to St. Louis trip
Airports
DEN

For a quick security experience at DEN, use the South checkpoint, which is open 24 hours. Reserve a time online for general screening.

Read more about DENby Emily Zemler
STL

Use the MetroLink from STL for a 40-minute ride to downtown St. Louis. It's economical and avoids traffic, ideal for light luggage.

Read more about STLby Taryn White
Our travel experts
Taryn White

Taryn White

Expert on STL

Taryn White

Taryn White

Taryn White is a freelance travel writer, digital creator, and travel advisor who has visited nearly 100 countries and all 50 states. She’s familiar with many airports and enjoys beach hopping, boutique hotels, spa experiences, and exploring local culture. Her work has appeared in Travel + Leisure, Condé Nast Traveler, National Geographic, Smithsonian Magazine, AFAR, and more.

Read more
Emily Zemler

Emily Zemler

Expert on DEN

Emily Zemler

Emily Zemler

Emily is a freelance writer and book author based in London covering entertainment and travel. Her work has appeared in Los Angeles Times, Observer, and Conde Nast Traveler She has ventured to more than 40 countries and all seven continents, always in search of a great art museum. She has written extensively about hotels, luxury travel, and aviation.

Read more

Best time to book a flight from Denver to St. Louis

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

How far ahead should I book a flight from Denver to St. Louis?

Use this chart to determine the optimal time to book a round-trip flight from Denver to St. Louis. Price data was last updated on September 12, 2025.

The price you pay for your flight from Denver to St. Louis may vary depending on when you book. For the best chance of a lower fare, look to book 74 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

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

Currently, August is the cheapest month in which you can book a flight from Denver to St. Louis (average of $311). Flying from Denver to St. Louis 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 DEN to STL?

Find hourly flight availability from Denver to St. Louis. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated September 19, 2025.

It’s optimal to fly from Denver to St. Louis in the evening. By choosing this option you can save up to 30% on the cost of your flight, compared to a flight in the afternoon.

What is the cheapest day to fly from Denver to St. Louis?

Use this chart to determine the cheapest time to fly round-trip from Denver to St. Louis. Price data was last updated on September 14, 2025.

Travelers seeking maximum savings on their Denver to St. Louis flight should consider departing on Friday evenings when fares are most often at their lowest. Monday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.

Reviews of airlines servicing St. Louis

Get insights into the airlines that provide service to St. Louis. 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. Louis. Reviews last updated September 19, 2025.
Get a feel of what it's like to fly with Southwest, United Airlines, and Frontier from Denver to St. Louis by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,242 reviews

Entertainment

7.5

Comfort

8.0

Overall

8.0

Boarding

8.1

Crew

8.6

Food

7.0

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Southwest
8.0
Very good
4,242 reviews
Southwest
8.0
Very good
4,242 reviews

Entertainment

7.5

Comfort

8.0

Overall

8.0

Boarding

8.1

Crew

8.6

Food

7.0

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
United Airlines
7.4
Good
8,926 reviews
Southwest
8.0
Very good
4,242 reviews

Entertainment

7.5

Comfort

8.0

Overall

8.0

Boarding

8.1

Crew

8.6

Food

7.0

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Frontier
5.8
Fair
3,171 reviews
Southwest
8.0
Very good
4,242 reviews

Entertainment

7.5

Comfort

8.0

Overall

8.0

Boarding

8.1

Crew

8.6

Food

7.0

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines

Related info for your journey

Find useful and relevant information for your journey from Denver to St. Louis. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airports do I use to fly from Denver to St. Louis?

    To fly from Denver to St. Louis, you need to book a flight from Denver Intl (DEN) to Lambert-St Louis (STL). Nonstop flights to Lambert-St Louis from Denver Intl take 2h 00m on average. When it comes time to book airfare, you have a few options: there are 14 outbound flights from Denver Intl to Lambert-St Louis offered by 3 different airlines.

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

    Within the past month, 38 users have taken a look at flights from Denver Intl to Lambert-St Louis.

  • How long is the flight from Denver to St. Louis?

    A quick flight from Denver to St. Louis can take about 2h 07m. Frontier provides one of the quickest options available for as low as $109. The distance from Denver to St. Louis is about 767 mi. Most flights are nonstop.

  • What are the cheapest airlines flying from Denver to St. Louis round-trip?

    Our cheapest airline available from Denver to St. Louis is Frontier. Our recent data shows that you can find tickets from as low as $57 on this airline. Additional options worth looking into are United Airlines and Southwest, starting at $154 and $173 round-trip. Frontier is currently priced 74% below the average price you’ll pay for this route.

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

    Looking for the most reliable airlines to get you to your destination on time? Our data shows these are most likely to get you from Denver to St. Louis on time: Frontier (87%), Air Canada (73%), United Airlines (72%).

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

    While on average a flight from Denver to St. Louis is generally $213, our data shows the cheapest flight currently is $71. When looking at the most popular route, (Denver Intl - Lambert-St Louis), you can expect to pay $128 for that flight.

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

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

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

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

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

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

    Currently, August is the cheapest month in which you can book a flight from Denver to St. Louis (average of $311). Flying from Denver to St. Louis 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.

See more FAQs

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
Edwardsville
O'Fallon
Fairview Heights
Maryland Heights
Collinsville
Eureka
Glencoe
St. Peters
Chesterfield
Alton
Farmington
Festus

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Alternative routes for Denver to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.
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Top 3 airlines flying from Denver to St. Louis

Discover the top 3 airlines that operate flights from Denver to St. Louis. 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 September 19, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$57Average$158FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$154Average$329FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$173Average$297FlexibilityNo cancel feeOn-time63%

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