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$71+ 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 10/8. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — STL
Jun 17 — Jun 241
Tue 6/17
Tue 6/24
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 August, booked 74 days in advance, depart on a Saturday 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 June 12, 2025.

Round-trip from

$146
(Cheapflightsfares)

One-way from

$73
(Kiwi.com)

Popular in

June

Cheapest in

January

Average price

$277

Good round-trip deal

$186 or less

Good one-way deal

$131 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. 6% potential increase in price ($14 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 June 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 June 12, 2025.

This Frontier deal was found by Cheapflights users on 6/10. 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 9/126:00 amDEN - STL
Nonstop2h 07mFrontier
Thu 9/187:52 pmSTL - DEN
Nonstop2h 28mFrontier
Deal found 6/10$129
This Southwest deal was found by Cheapflights users on 6/12. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/142:10 pmDEN - STL
1 stop3h 25mSouthwest
Mon 8/186:40 pmSTL - DEN
Nonstop2h 20mSouthwest
Deal found 6/12$163
This American Airlines deal was found by Cheapflights users on 6/12. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/2411:59 pmDEN - STL
1 stop7h 06mAmerican Airlines
Mon 9/293:57 pmSTL - DEN
1 stop6h 04mAmerican Airlines
Deal found 6/12$177
This Delta deal was found by Cheapflights users on 6/10. 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.
Mon 9/1512:59 amDEN - STL
1 stop6h 11mDelta
Mon 9/225:30 pmSTL - DEN
1 stop6h 00mDelta
Deal found 6/10$197
This United Airlines deal was found by Cheapflights users on 6/10. 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 9/161:26 pmDEN - STL
Nonstop2h 07mUnited Airlines
Sat 9/203:20 pmSTL - DEN
1 stop5h 52mUnited Airlines
Deal found 6/10$274

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 June 12, 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 9/12

6:00 am-9:07 am

Nonstop2h 07m

Lambert-St Louis

Thu 9/18

7:52 pm-9:20 pm

Nonstop2h 28m

$129

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Thu 8/14

2:10 pm-6:35 pm

1 stop3h 25m

Lambert-St Louis

Mon 8/18

6:40 pm-8:00 pm

Nonstop2h 20m

$163

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Wed 9/24

11:59 pm-8:05 am

1 stop7h 06m

Lambert-St Louis

Mon 9/29

3:57 pm-9:01 pm

1 stop6h 04m

$177

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Mon 9/15

12:59 am-8:10 am

1 stop6h 11m

Lambert-St Louis

Mon 9/22

5:30 pm-10:30 pm

1 stop6h 00m

$197

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Tue 9/16

1:26 pm-4:33 pm

Nonstop2h 07m

Lambert-St Louis

Sat 9/20

3:20 pm-8:12 pm

1 stop5h 52m

$274

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Thu 7/3

6:13 pm-11:30 am

1 stop16h 17m

Lambert-St Louis

Sun 7/6

6:36 am-8:55 am

1 stop27h 19m

$345

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Wed 10/8

12:59 am-10:07 am

1 stop8h 08m

$71

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Thu 8/7

6:42 pm-9:50 pm

Nonstop2h 08m

$79

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Wed 10/15

12:20 pm-7:08 pm

1 stop5h 48m

$88

DenverSt. Louis

DEN - STL

DENSTL

Denver Intl

Sat 7/12

5:25 am-8:25 am

Nonstop2h 00m

$89

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/11

Showing 1-10 of 14 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 June 9, 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 June 12, 2025.

It’s optimal to fly from Denver to St. Louis in the evening. By choosing this option you can save up to 35% 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 June 8, 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 June 12, 2025.

The most flights from DEN to STL are scheduled on a Wednesday (17 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (7 on average).

Rainfall in St. Louis by month

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

In terms of precipitation, rainfall in St. Louis 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. Louis when rainfall is around 2.2 in.

Temperature in St. Louis by month

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

If weather is an important factor for your trip to St. Louis, 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. 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 June 12, 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. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Overall

8.0

Boarding

8.1

Food

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Overall

8.0

Boarding

8.1

Food

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Southwest
8.0
Very good
4,287 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Overall

8.0

Boarding

8.1

Food

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Delta
8.0
Very good
7,946 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Overall

8.0

Boarding

8.1

Food

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
United Airlines
7.4
Good
8,790 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Overall

8.0

Boarding

8.1

Food

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Overall

8.0

Boarding

8.1

Food

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

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, 26 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 $146 on this airline. Additional options worth looking into are Southwest and American Airlines, starting at $167 and $182 round-trip. Frontier is currently priced 31% 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 $73. Users have also found prices from $79 and $89 on United 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 (85%), Air Canada (71%), United Airlines (66%).

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

    While on average a flight from Denver to St. Louis is generally $241, our data shows the cheapest flight currently is $74. When looking at the most popular route, (Denver Intl - Lambert-St Louis), you can expect to pay $127 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 Denver?

Book flights to Denver if you plan to visit one of these locations
O'Fallon
Maryland Heights
Fairview Heights
Collinsville
Eureka
St. Peters
Glencoe
Festus
Alton
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 June 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$45Average$146FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$150Average$316FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$177Average$301FlexibilityNo cancel feeOn-time63%

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