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$78+ Cheap flights from St. Louis to Denver (STL - DEN)

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 6/2. Fares are subject to change and may not be available on all flights or dates of travel.
STL — DEN
May 4 — May 111
Sun 5/4
Sun 5/11
1 adult, Economy
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1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

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Cheapflights Tip: The best prices from Lambert-St Louis to Denver Intl are usually found in August or September, booked 23 days in advance, depart on a Friday or Wednesday and return on a Saturday

Cheap flight deals from St. Louis to Denver

Discover tips and strategies to find the most affordable flight options for your journey from St. Louis (STL) to Denver (DEN). 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 April 29, 2025.

Most accurate provider

CheapOair
3 stars

Most trusted provider

CheapOair
3 stars

Round-trip from

$96
(Cheapflightsfares)

One-way from

$78
(Cheapflightsfares)

Popular in

March

Cheapest in

August

Average price

$191

Good round-trip deal

$254 or less

Good one-way deal

$128 or less
Provider with most accurate pricing for Lambert-St Louis-Denver Intl flight deals.
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Provider most trusted by Cheapflights users for Lambert-St Louis-Denver Intl flights.
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From Lambert-St Louis to Denver Intl
Search Deals
One-way flight from Lambert-St Louis to Denver Intl
Search Deals
Highest demand for flights based on searches. 21% potential increase in price ($53 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 7% potential price decrease ($13 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in April 2025
Search Deals
Price to beat on a round-trip flight from Lambert-St Louis to Denver Intl.
Search Deals
Price to beat on a one-way flight from Lambert-St Louis to Denver Intl.
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Find flight deals from St. Louis to Denver

Cheapest flights from St. Louis to Denver
Explore the most affordable flight options available from St. Louis to Denver. Find the lowest fares from popular airlines and budget airlines, with prices last updated on April 29, 2025.

This Cheapflightsfares deal was found by Cheapflights users on 4/28. 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.
Wed 5/287:55 pmSTL - DEN
Nonstop2h 32mFrontier
Wed 6/47:00 amDEN - STL
Nonstop2h 08mFrontier
Deal found 4/28$96
This Delta deal was found by Cheapflights users on 4/28. 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.
Wed 6/115:44 pmSTL - DEN
1 stop6h 38mDelta
Wed 6/1812:15 pmDEN - STL
1 stop5h 29mDelta
Deal found 4/28$217
This Southwest deal was found by Cheapflights users on 4/27. 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 7/235:35 amSTL - DEN
1 stop5h 55mSouthwest
Tue 7/297:05 pmDEN - STL
Nonstop2h 05mSouthwest
Deal found 4/27$220
This CheapOair deal was found by Cheapflights users on 4/28. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/126:53 pmSTL - DEN
Nonstop2h 29mMultiple Airlines
Thu 5/156:30 pmDEN - STL
1 stop16h 07mMultiple Airlines
Deal found 4/28$239
This American Airlines deal was found by Cheapflights users on 4/27. 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.
Thu 5/225:00 amSTL - DEN
1 stop4h 36mAmerican Airlines
Tue 5/2711:59 pmDEN - STL
1 stop7h 57mAmerican Airlines
Deal found 4/27$244
This United Airlines deal was found by Cheapflights users on 4/27. 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.
Thu 6/54:32 pmSTL - DEN
Nonstop2h 29mUnited Airlines
Mon 6/95:40 pmDEN - STL
Nonstop2h 08mUnited Airlines
Deal found 4/27$251

Cheapflights Fare Finder

Customize your flight search to find flights from St. Louis to Denver 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 April 29, 2025.
Use the filters below to find and compare flights from St. Louis to Denver that are best for you.

Fly from

St. Louis

Fly to

Denver

Route

Depart

Return

Price

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 5/28

7:55 pm-9:27 pm

Nonstop2h 32m

Denver Intl

Wed 6/4

7:00 am-10:08 am

Nonstop2h 08m

$96

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 6/11

5:44 pm-11:22 pm

1 stop6h 38m

Denver Intl

Wed 6/18

6:00 am-2:37 pm

1 stop7h 37m

$217

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 7/23

5:35 am-10:30 am

1 stop5h 55m

Denver Intl

Tue 7/29

7:05 pm-10:10 pm

Nonstop2h 05m

$220

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Mon 5/12

6:53 pm-8:22 pm

Nonstop2h 29m

Denver Intl

Thu 5/15

6:30 pm-11:37 am

1 stop16h 07m

$239

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Thu 5/22

5:00 am-8:36 am

1 stop4h 36m

Denver Intl

Tue 5/27

11:59 pm-8:56 am

1 stop7h 57m

$244

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Thu 6/5

4:32 pm-6:01 pm

Nonstop2h 29m

Denver Intl

Mon 6/9

5:40 pm-8:48 pm

Nonstop2h 08m

$251

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Mon 6/2

7:24 pm-8:51 pm

Nonstop2h 27m

$78

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sat 7/26

5:20 am-6:40 am

Nonstop2h 20m

$99

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sun 5/25

10:20 am-5:27 pm

1 stop8h 07m

$103

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 5/28

6:05 pm-12:12 am

1 stop7h 07m

$109

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/27

Showing 1-10 of 14 results
1
2

Compare providers for flights from St. Louis to Denver

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from St. Louis to Denver in April.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*2 stars
eDreamsPrice Accuracy3 starsTrust Score*3 stars
CheapflightsfaresPrice Accuracy3 starsTrust Score*2 stars
JustAirTicketPrice Accuracy-Trust Score*3 stars
CheapOairPrice Accuracy3 starsTrust Score*3 stars
FlightnetworkPrice Accuracy-Trust Score*3 stars
GotogatePrice Accuracy3 starsTrust Score*2 stars
PricelinePrice Accuracy2 starsTrust Score*3 stars
CheapTicketsDealPrice Accuracy3 starsTrust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on St. Louis-Denver flights, users find the pricing of CheapOair to be most consistent on Cheapflights vs. CheapOair Users can find the same prices on St. Louis-Denver flight deals on Cheapflights vs. CheapOair >95% of the time. Price accuracy is based on data collected from St. Louis-Denver flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on St. Louis-Denver flights, Cheapflights users trust CheapOair the most. CheapOair has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for St. Louis-Denver flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

The best insider tips for St. Louis to Denver 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 St. Louis to Denver trip
Airlines
Frontier

Frontier's UpFront Plus guarantees an empty middle seat for extra comfort.


Early check-in helps secure your place due to frequent overbooking.

Read more about Frontierby Marisa Garcia
United Airlines

Basic Economy allows a personal item only; no carry-on bags without extra fees.


Economy Plus offers extra legroom seats at the front of the economy cabin.

Read more about United Airlinesby Harriet Baskas
Airports
STL

Expect security screening at STL to take 5-10 minutes during off-peak times. Check real-time wait times online before heading to the airport.

Read more about STLby Taryn White
DEN

Take the A Line train from DEN to Union Station in 37 minutes. It runs every 15 minutes, offering a convenient city connection.

Read more about DENby Emily Zemler
Our travel experts
Marisa Garcia

Marisa Garcia

Expert on Frontier

Marisa Garcia

Marisa Garcia

Marisa knows planes inside and out, spending 16 years working on aircraft in hangars at airports around the world. She is an aviation industry expert, specialized in airline interiors and regulations. Ten years ago, she pivoted to journalism. She shares her insights in leading aviation, travel, and business publications and on her site FlightChic.

Read more
Harriet Baskas

Harriet Baskas

Expert on United Airlines

Harriet Baskas

Harriet Baskas

Harriet is an award-winning journalist who is happiest in an airport or an unusual museum. Her stories about airports, air travel, and the business of travel have appeared on NBC News, CNBC, USA TODAY, The Points Guy and other outlets. She is the creator of the StuckatTheAirport.com blog and the author of nine books. When not out on the road or exploring the latest airport amenities, she’s home in Seattle getting ready for the next adventure.

Read more
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 St. Louis to Denver

Have a flexible travel schedule? Discover the best time to fly to Denver 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 Denver

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

Use this chart to determine the optimal time to book a round-trip flight from St. Louis to Denver. Price data was last updated on April 25, 2025.

Booking 23 days in advance of your planned departure date is, on average, the best time to get cheap flights from St. Louis to Denver. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

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

Currently, October is the cheapest month in which you can book a flight from St. Louis to Denver (average of $197). Flying from St. Louis to Denver in March is currently the most expensive (average of $278). 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 DEN?

Find hourly flight availability from St. Louis to Denver. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated April 29, 2025.

It’s optimal to fly from St. Louis to Denver in the evening. By choosing this option you can save up to 69% on the cost of your flight, compared to a flight in the morning.

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

Use this chart to determine the cheapest time to fly round-trip from St. Louis to Denver. Price data was last updated on March 30, 2025.

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

Weekly flight availability from St. Louis to Denver

Explore weekly flight availability from St. Louis to Denver. 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 April 29, 2025.

The most flights from STL to DEN are scheduled on a Wednesday (16 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (11 on average).

Rainfall in Denver by month

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

In terms of precipitation, rainfall in Denver ranges from 0.5 - 2.3 inches per month. May is typically the wettest month, when rainfall can reach 2.3 in. January is typically the driest time to visit Denver when rainfall is around 0.5 in.

Temperature in Denver by month

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

If weather is an important factor for your trip to Denver, 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 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 30.2 F).

Reviews of airlines servicing Denver

Get insights into the airlines that provide service to Denver. 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 Denver. Reviews last updated April 29, 2025.
Read through reviews of airlines operating flights from St. Louis to Denver, such as Alaska Airlines, Southwest and Delta. In addition to providing an overall rating, users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
9,949 reviews

Boarding

8.2

Crew

8.5

Comfort

7.9

Overall

8.0

Entertainment

7.1

Food

7.1

Reviews

1 / 20
4.0
Okay

Anonymous,Apr 2025

LAS - STS

flight was delayed both ways even tho the weather was clear >
Alaska Airlines
8.0
Very good
9,949 reviews
Alaska Airlines
8.0
Very good
9,949 reviews

Boarding

8.2

Crew

8.5

Comfort

7.9

Overall

8.0

Entertainment

7.1

Food

7.1

Reviews

1 / 20
4.0
Okay

Anonymous,Apr 2025

LAS - STS

flight was delayed both ways even tho the weather was clear >
Southwest
8.0
Very good
4,292 reviews
Alaska Airlines
8.0
Very good
9,949 reviews

Boarding

8.2

Crew

8.5

Comfort

7.9

Overall

8.0

Entertainment

7.1

Food

7.1

Reviews

1 / 20
4.0
Okay

Anonymous,Apr 2025

LAS - STS

flight was delayed both ways even tho the weather was clear >
Delta
8.0
Very good
7,929 reviews
Alaska Airlines
8.0
Very good
9,949 reviews

Boarding

8.2

Crew

8.5

Comfort

7.9

Overall

8.0

Entertainment

7.1

Food

7.1

Reviews

1 / 20
4.0
Okay

Anonymous,Apr 2025

LAS - STS

flight was delayed both ways even tho the weather was clear >
United Airlines
7.4
Good
8,696 reviews
Alaska Airlines
8.0
Very good
9,949 reviews

Boarding

8.2

Crew

8.5

Comfort

7.9

Overall

8.0

Entertainment

7.1

Food

7.1

Reviews

1 / 20
4.0
Okay

Anonymous,Apr 2025

LAS - STS

flight was delayed both ways even tho the weather was clear >
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
9,949 reviews

Boarding

8.2

Crew

8.5

Comfort

7.9

Overall

8.0

Entertainment

7.1

Food

7.1

Reviews

1 / 20
4.0
Okay

Anonymous,Apr 2025

LAS - STS

flight was delayed both ways even tho the weather was clear >

Related info for your journey

Find useful and relevant information for your journey from St. Louis to Denver. 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 St. Louis to Denver?

    You will need to book a flight from Lambert-St Louis to Denver Intl if you want to fly from St. Louis to Denver. At least 5 different airlines have flights from Lambert-St Louis (STL) to Denver Intl (DEN) on a regular basis. There are 14 flights to Denver from the St. Louis airport per day. If you manage to book one that is nonstop, then you can expect the flight time from STL to DEN to be around 2h 15m.

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

    Flights from Lambert-St Louis to Denver Intl have been viewed 199 times in the past calendar month.

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

    Frontier, at $96, was found to be the cheapest airline from St. Louis to Denver.Alternate airlines to your destination round-trip include Southwest and Delta. Users have found that Frontier is 50% cheaper than the other options available to this destination.

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

    One-way options have recently been found by users for as low as $78 on Frontier. Other airlines that offer cheap prices include Southwest from $99 and Sun Country Air from $103 one-way.

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

    No one likes to see their flight delayed. When booking a flight from St. Louis to Denver consider choosing Southwest (85%), Air Canada (79%) or United Airlines (73%) as they are the most reliable in getting you off to your destination on time.

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

    Looking for the cheapest flight from St. Louis to Denver? While on average our users pay $834, our data indicates the cheapest price to be $86. The most popular route (Lambert-St Louis - Denver Intl), is priced around $154.

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

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

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

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

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

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

    Currently, October is the cheapest month in which you can book a flight from St. Louis to Denver (average of $197). Flying from St. Louis to Denver in March is currently the most expensive (average of $278). 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
Westminster
Black Hawk
Winter Park
Lakewood
Cripple Creek
Silverthorne
Brighton
Golden
Greeley
Frisco
Grand Lake
Thornton
Central City
Glendale
Copper Mountain
Wheat Ridge
Longmont
Broomfield
Idaho Springs
Limon

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Alternative routes for St. Louis to Denver

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Top 5 airlines flying from St. Louis to Denver

Discover the top 5 airlines that operate flights from St. Louis to Denver. 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 April 29, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$46Average$114FlexibilityNo cancel feeOn-time62%
DeltaCheapest$128Average$256FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$153Average$310FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$178Average$301FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$192Average$271FlexibilityNo cancel feeOn-time71%

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