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$79+ 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 9/2. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — STL
Jul 26 — Aug 21
Sat 7/26
Sat 8/2
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 February, booked 74 days in advance, depart on a Wednesday or Friday 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 July 21, 2025.

Round-trip from

$143
(Cheapflightsfares)

One-way from

$79
(Cheapflightsfares)

Popular in

June

Cheapest in

January

Average price

$222

Good round-trip deal

$177 or less

Good one-way deal

$110 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. 11% potential increase in price ($28 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 July 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 July 21, 2025.

This Cheapflightsfares deal was found by Cheapflights users on 7/19. 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 8/16:00 amDEN - STL
Nonstop2h 11mFrontier
Mon 8/47:29 pmSTL - DEN
Nonstop2h 29mFrontier
Deal found 7/19$143
This Southwest deal was found by Cheapflights users on 7/20. 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.
Thu 8/145:30 amDEN - STL
Nonstop2h 00mSouthwest
Sat 8/165:45 amSTL - DEN
Nonstop2h 15mSouthwest
Deal found 7/20$157
This American Airlines deal was found by Cheapflights users on 7/20. 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 8/2310:31 amDEN - STL
1 stop6h 59mAmerican Airlines
Mon 8/255:52 pmSTL - DEN
1 stop5h 23mAmerican Airlines
Deal found 7/20$177
This Delta deal was found by Cheapflights users on 7/21. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/2212:59 amDEN - STL
1 stop6h 55mDelta
Tue 9/27:35 amSTL - DEN
1 stop5h 16mDelta
Deal found 7/21$197

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 July 21, 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

Fri 8/1

6:00 am-9:11 am

Nonstop2h 11m

Lambert-St Louis

Mon 8/4

7:29 pm-8:58 pm

Nonstop2h 29m

$143

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Thu 8/14

5:30 am-8:30 am

Nonstop2h 00m

Lambert-St Louis

Sat 8/16

5:45 am-7:00 am

Nonstop2h 15m

$157

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Sat 8/23

10:31 am-6:30 pm

1 stop6h 59m

Lambert-St Louis

Mon 8/25

5:52 pm-10:15 pm

1 stop5h 23m

$177

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Fri 8/22

12:59 am-8:54 am

1 stop6h 55m

Lambert-St Louis

Tue 9/2

7:35 am-11:51 am

1 stop5h 16m

$197

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Tue 9/2

6:00 am-9:11 am

Nonstop2h 11m

$79

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Thu 8/21

11:59 pm-9:29 am

1 stop8h 30m

$89

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Sat 8/30

9:30 am-5:10 pm

2 stops6h 40m

$94

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Mon 8/18

12:59 am-9:57 am

1 stop7h 58m

$99

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Mon 11/24

7:46 am-3:46 pm

1 stop7h 00m

$156

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Mon 10/20

8:41 am-9:40 am

2 stops23h 59m

$159

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/19

Showing 1-10 of 11 results
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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 July 18, 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 July 21, 2025.

It’s optimal to fly from Denver to St. Louis in the evening. By choosing this option you can save up to 36% on the cost of your flight, compared to a flight at noon.

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 July 20, 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.

Weekly flight availability from Denver to St. Louis

Explore weekly flight availability from Denver to St. Louis. 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 July 21, 2025.

The most flights from DEN to STL are scheduled on a Sunday (18 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (6 on average).

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 July 21, 2025.
Get a feel of what it's like to fly with Alaska Airlines, Southwest, and Delta 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.
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Food

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Food

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Southwest
8.0
Very good
4,233 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Food

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Delta
8.0
Very good
7,962 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Food

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
United Airlines
7.4
Good
8,867 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Food

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Food

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.

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 13 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, 29 users have taken a look at flights from Denver Intl to Lambert-St Louis.

  • 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 $143 on this airline. Additional options worth looking into are Southwest and American Airlines, starting at $157 and $177 round-trip. Frontier is currently priced 35% below the average price you’ll pay for this route.

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

    For one-way options, check prices for Frontier. According to our data, you can fly for as low as $79. Users have also found prices from $89 and $94 on American Airlines and Southwest, respectively.

  • 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 (91%), United Airlines (72%), Air Canada (64%).

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

    While on average a flight from Denver to St. Louis is generally $208, our data shows the cheapest flight currently is $78. When looking at the most popular route, (Denver Intl - Lambert-St Louis), you can expect to pay $147 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
O'Fallon
Maryland Heights
Fairview Heights
Collinsville
Eureka
St. Peters
Glencoe
Alton
Festus
Chesterfield
Farmington

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Alternative routes for Denver to St. Louis

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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 July 21, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$46Average$152FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$151Average$318FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$177Average$300FlexibilityNo cancel feeOn-time63%

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