HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Denver

$39+ 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 2/21. Fares are subject to change and may not be available on all flights or dates of travel.
STL — DEN
ene. 28 — feb. 41
mar. 1/28
mar. 2/4
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from St. Louis to Denver with Cheapflights

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”
2. Select your favorite providers
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.
3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

The best prices from Lambert-St Louis to Denver Intl are usually found in April or May, booked 23 days in advance, depart on a Friday or Wednesday and return on a Tuesday

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 enero 23, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$57
(Kiwi.com)

One-way from

$39
(Frontier)

Popular in

December

Cheapest in

April

Average price

$170

Good round-trip deal

$173 or less

Good one-way deal

$119 or less
Provider with most accurate pricing for Lambert-St Louis-Denver Intl flight deals.
Search Deals
Provider most trusted by Cheapflights users for Lambert-St Louis-Denver Intl flights.
Search Deals
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. 12% potential increase in price ($22 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease ($7 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in January 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.
Search Deals

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 enero 23, 2025.

This Kiwi.com deal was found by Cheapflights users on 1/22. 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.
mié. 2/57:09 pmSTL - DEN
Nonstop2h 28mFrontier
mié. 2/126:00 amDEN - STL
Nonstop2h 16mFrontier
Deal found 1/22$57
This Southwest deal was found by Cheapflights users on 1/23. 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.
jue. 2/275:45 amSTL - DEN
Nonstop2h 35mSouthwest
mar. 3/47:20 pmDEN - STL
Nonstop2h 00mSouthwest
Deal found 1/23$177
This United Airlines deal was found by Cheapflights users on 1/23. 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.
jue. 2/271:39 pmSTL - DEN
Nonstop2h 31mUnited Airlines
mar. 3/47:47 amDEN - STL
1 stop5h 49mUnited Airlines
Deal found 1/23$187
This Delta deal was found by Cheapflights users on 1/22. 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.
mar. 2/256:43 amSTL - DEN
1 stop8h 13mDelta
jue. 3/62:21 pmDEN - STL
1 stop6h 56mDelta
Deal found 1/22$207
This American Airlines deal was found by Cheapflights users on 1/23. 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.
mié. 2/197:04 amSTL - DEN
1 stop7h 45mAmerican Airlines
mié. 2/194:17 pmDEN - STL
1 stop6h 39mAmerican Airlines
Deal found 1/23$211

Find flights from St. Louis to Denver within your budget

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 enero 23, 2025.

Fly from

Any airport

Fly to

Any airport

Route

Depart

Return

Price

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

mié. 2/5

7:09 pm-8:37 pm

Nonstop2h 28m

Denver Intl

mié. 2/12

6:00 am-9:16 am

Nonstop2h 16m

$57

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

jue. 2/27

5:45 am-7:20 am

Nonstop2h 35m

Denver Intl

mar. 3/4

7:20 pm-10:20 pm

Nonstop2h 00m

$177

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

jue. 2/27

1:39 pm-3:10 pm

Nonstop2h 31m

Denver Intl

mar. 3/4

7:47 am-2:36 pm

1 stop5h 49m

$187

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

mar. 2/25

6:43 am-1:56 pm

1 stop8h 13m

Denver Intl

jue. 3/6

2:21 pm-10:17 pm

1 stop6h 56m

$207

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

mié. 2/19

7:04 am-1:49 pm

1 stop7h 45m

Denver Intl

mié. 2/19

4:17 pm-11:56 pm

1 stop6h 39m

$211

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

vie. 2/21

7:09 pm-8:37 pm

Nonstop2h 28m

$39

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

mar. 5/20

1:41 pm-3:10 pm

Nonstop2h 29m

$99

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

mar. 5/20

5:20 am-8:50 am

1 stop4h 30m

$104

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

mié. 3/12

5:00 pm-10:31 pm

1 stop6h 31m

$109

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

mar. 3/18

5:38 pm-5:13 pm

3 stops24h 35m

$180

Flights are sorted by cheapest round-trip flights first.

Deals found on 1/22

Showing 1-10 of 11 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 January.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
eDreamsPrice Accuracy3 starsTrust Score*3 stars
CheapflightsfaresPrice Accuracy3 starsTrust Score*1 star
AranGrantPrice Accuracy3 starsTrust Score*3 stars
FlightnetworkPrice Accuracy-Trust Score*3 stars
CheapOairPrice Accuracy2 starsTrust Score*2 stars
GotogatePrice Accuracy2 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 FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on St. Louis-Denver flight deals on Cheapflights vs. FlightHub >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 FlightHub the most. FlightHub 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.

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.

Travel insights for flights from St. Louis to Denver

Get recent, data-driven insights about flights from St. Louis to Denver including ideal travel times, pricing trends, and more.

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 January 17, 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 enero 23, 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 January 21, 2025.

Travelers seeking maximum savings on their St. Louis to Denver flight should consider departing on Wednesday 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 enero 23, 2025.

The most flights from STL to DEN are scheduled on a Monday (20 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (6 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 enero 23, 2025.
Read through reviews of airlines operating flights from St. Louis to Denver, such as Frontier, Southwest and United Airlines. In addition to providing an overall rating, users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.1
Very good
4,647 reviews

Overall

8.1

Boarding

8.2

Entertainment

7.7

Crew

8.7

Food

7.2

Comfort

8.1

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Southwest
8.1
Very good
4,647 reviews
Southwest
8.1
Very good
4,647 reviews

Overall

8.1

Boarding

8.2

Entertainment

7.7

Crew

8.7

Food

7.2

Comfort

8.1

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Alaska Airlines
8.0
Very good
9,699 reviews
Southwest
8.1
Very good
4,647 reviews

Overall

8.1

Boarding

8.2

Entertainment

7.7

Crew

8.7

Food

7.2

Comfort

8.1

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Delta
8.0
Very good
8,508 reviews
Southwest
8.1
Very good
4,647 reviews

Overall

8.1

Boarding

8.2

Entertainment

7.7

Crew

8.7

Food

7.2

Comfort

8.1

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

United Airlines
7.4
Good
8,971 reviews
Southwest
8.1
Very good
4,647 reviews

Overall

8.1

Boarding

8.2

Entertainment

7.7

Crew

8.7

Food

7.2

Comfort

8.1

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

American Airlines
7.2
Good
10,000 reviews
Southwest
8.1
Very good
4,647 reviews

Overall

8.1

Boarding

8.2

Entertainment

7.7

Crew

8.7

Food

7.2

Comfort

8.1

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

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 12 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 20m.

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

    Flights from Lambert-St Louis to Denver Intl have been viewed 230 times in the past calendar month.

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

    Frontier, at $57, was found to be the cheapest airline from St. Louis to Denver.Alternate airlines to your destination round-trip include Southwest and United Airlines. Users have found that Frontier is 66% 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 $39 on Frontier. Other airlines that offer cheap prices include United Airlines from $99 and Southwest from $104 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 Frontier (87%), Southwest (77%) or United Airlines (64%) 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 $610, our data indicates the cheapest price to be $52. The most popular route (Lambert-St Louis - Denver Intl), is priced around $125.

  • 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
Keystone
Westminster
Black Hawk
Winter Park
Dillon
Lakewood
Broomfield
Silverthorne
Golden
Brighton
Frisco
Wheat Ridge
Grand Lake
Idaho Springs
Greeley
Central City
Copper Mountain
Longmont
Thornton
Limon

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for St. Louis to Denver

See prices for flight routes from nearby airports that may be better suited for you.
Kansas City to Denver flights
Springfield to Denver flights
Kansas City to Colorado Springs flights
St. Louis to Montrose flights
St. Louis to Vail flights
Joplin to Denver flights
Kansas City to Grand Junction flights
St. Louis to Durango flights
St. Louis to Colorado Springs flights
Kansas City to Hayden flights
St. Louis to Gunnison flights
Kansas City to Durango flights
Kansas City to Aspen flights
St. Louis to Aspen flights
Springfield to Colorado Springs flights
St. Louis to Grand Junction flights
St. Louis to Hayden flights
Columbia to Denver flights
Joplin to Colorado Springs flights
Branson to Denver flights
Columbia to Colorado Springs flights
Cape Girardeau to Denver flights
Kansas City to Cortez flights
Columbia to Aspen flights
St. Louis to Cortez flights
Springfield to Hayden flights
Kansas City to Alamosa flights

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 enero 23, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$46Average$118FlexibilityNo cancel feeOn-time62%
DeltaCheapest$131Average$255FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$150Average$311FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$171Average$295FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$192Average$242FlexibilityNo cancel feeOn-time71%
100% Free
Cheapflights is completely free to use, so you can start saving the moment you arrive.
Book with Flexibility
Our users can plan ahead with confidence and find flights with no change fees
Travel Smart
Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.