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

Flights from Lambert-St Louis to Denver Intl have been viewed 174 times in the past calendar month.

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

Departing from St. Louis to Denver will take you 2h 25m. Airlines will cover a distance of 767 mi. Both multi-stop and nonstop flights can be found to your destination and back.

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

Frontier, at $46, was found to be the cheapest airline from St. Louis to Denver.Alternate airlines to your destination round-trip include Delta and United Airlines. Users have found that Frontier is 80% 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 $32 on Frontier. Other airlines that offer cheap prices include Southwest from $78 and United Airlines from $89 one-way.

Weekly flight availability from St. Louis to Denver

The most flights from STL to DEN are scheduled on a Wednesday (9 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (4 on average).

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.

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).

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 $1,098, our data indicates the cheapest price to be $76. The most popular route (Lambert-St Louis - Denver Intl), is priced around $116.

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 SkyWest Airlines (100%), Frontier (91%) or Air Canada (79%) as they are the most reliable in getting you off to your destination on time.

What are the most popular airlines that fly from St. Louis to Denver?

When booking a flight from St. Louis to Denver, you may want to consider flying on Frontier, Southwest or United Airlines as they are the most popular for this route.

Most accurate provider : When it comes to deals on St. Louis-Denver flights, users find the pricing of eDreams to be most consistent on Cheapflights vs. eDreams Users can find the same prices on St. Louis-Denver flight deals on Cheapflights vs. eDreams >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 eDreams the most. eDreams 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.

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 5 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.

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.

$54+ Flights from St. Louis to Denver

Home Search by date Vacation packages Hotels Flight deals Car rental Travel tips & news

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.

Cheapflights Tip: The best prices from Lambert-St Louis to Denver Intl are usually found in October or January, booked 75 days in advance, depart on a Wednesday or Friday and return on a Friday

Cheap 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 December 25, 2025.

Wed 12/314:27 pmSTL - DEN

1 stop7h 37mFrontier

Mon 1/56:15 amDEN - STL

1 stop12h 52mFrontier

Deal found 12/22

$212

Thu 12/2510:42 amSTL - DEN

1 stop12h 26mFrontier

Thu 1/111:59 pmDEN - STL

1 stop7h 13mFrontier

Deal found 12/22

$264

Wed 12/314:27 pmSTL - DEN

1 stop7h 37mFrontier

Sun 1/411:59 pmDEN - STL

1 stop8h 46mFrontier

Deal found 12/23

$267

Thu 12/2510:42 amSTL - DEN

1 stop12h 26mFrontier

Sun 1/411:59 pmDEN - STL

1 stop8h 46mFrontier

Deal found 12/22

$268

Best flights from St. Louis to Denver
Discover carefully curated flight deals from St. Louis to Denver that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated December 25, 2025.

Sat 1/246:05 pmSTL - DEN

Nonstop2h 25mSouthwest

Mon 1/267:00 amDEN - STL

Nonstop2h 15mSouthwest

Deal found 12/23

$177

Fri 1/28:42 pmSTL - DEN

1 stop13h 13mFrontier

Wed 1/76:33 pmDEN - STL

1 stop27h 00mFrontier

Deal found 12/24

$187

Fri 1/239:59 amSTL - DEN

1 stop6h 39mDelta

Fri 1/2312:30 amDEN - STL

1 stop7h 23mDelta

Deal found 12/23

$197

Mon 1/128:45 amSTL - DEN

Nonstop2h 36mUnited Airlines

Wed 1/1410:10 amDEN - STL

Nonstop2h 06mUnited Airlines

Deal found 12/22

$217

Wed 2/188:17 pmSTL - DEN

1 stop12h 22mMultiple Airlines

Sun 2/223:08 pmDEN - STL

2 stops26h 28mMultiple Airlines

Deal found 12/24

$219

Sat 1/37:43 pmSTL - DEN

Nonstop2h 32mFrontier

Sat 1/106:50 amDEN - STL

Nonstop2h 12mFrontier

Deal found 12/23

$228

Fri 2/66:00 pmSTL - DEN

Nonstop2h 38mUnited Airlines

Tue 2/1010:10 amDEN - STL

Nonstop2h 06mUnited Airlines

Deal found 12/24

$237

Fri 1/166:10 amSTL - DEN

1 stop5h 21mDelta

Wed 1/212:42 pmDEN - STL

1 stop7h 55mDelta

Deal found 12/24

$237

Sat 1/104:15 pmSTL - DEN

Nonstop2h 38mUnited Airlines

Wed 1/1410:10 amDEN - STL

Nonstop2h 06mUnited Airlines

Deal found 12/25

$257

Fri 2/206:00 pmSTL - DEN

Nonstop2h 34mUnited Airlines

Sun 3/15:25 pmDEN - STL

Nonstop2h 01mUnited Airlines

Deal found 12/22

$262

Fri 1/238:45 amSTL - DEN

Nonstop2h 36mUnited Airlines

Sun 1/251:53 pmDEN - STL

Nonstop2h 02mUnited Airlines

Deal found 12/23

$262

Last-minute flights from St. Louis to Denver
Discover last-minute flight deals from St. Louis to Denver. Data last updated December 25, 2025 and is based on user searches.

Wed 12/314:27 pmSTL - DEN

1 stop7h 37mFrontier

Mon 1/56:15 amDEN - STL

1 stop12h 52mFrontier

Deal found 12/22

$212

Fri 1/28:42 pmSTL - DEN

1 stop13h 13mFrontier

Wed 1/76:50 amDEN - STL

Nonstop2h 12mFrontier

Deal found 12/24

$160

Fri 1/28:42 pmSTL - DEN

1 stop13h 13mFrontier

Mon 1/59:24 amDEN - STL

1 stop12h 09mFrontier

Deal found 12/24

$207

Sat 1/37:43 pmSTL - DEN

Nonstop2h 32mFrontier

Sat 1/106:50 amDEN - STL

Nonstop2h 12mFrontier

Deal found 12/23

$228

Sun 1/410:10 pmSTL - DEN

1 stop6h 48mFrontier

Fri 1/96:50 amDEN - STL

Nonstop2h 12mFrontier

Deal found 12/23

$220

Sun 1/410:10 pmSTL - DEN

1 stop6h 48mFrontier

Sun 1/116:02 pmDEN - STL

1 stop17h 10mFrontier

Deal found 12/24

$251

One-way flights from St. Louis to Denver
Search for one-way flight options from St. Louis to Denver. Find affordable one-way fares based on user searches. Data last updated December 25, 2025.

Fri 1/97:43 pmSTL - DEN

Nonstop2h 32mFrontier

Deal found 12/23

$54

Sat 2/73:46 pmSTL - DEN

Nonstop2h 37mFrontier

Deal found 12/24

$61

Sat 1/107:43 pmSTL - DEN

Nonstop2h 32mFrontier

Deal found 12/25

$63

Wed 2/113:49 pmSTL - DEN

1 stop8h 10mFrontier

Deal found 12/25

$64

Wed 2/184:51 pmSTL - DEN

Nonstop2h 34mFrontier

Deal found 12/25

$65

Mon 3/21:54 pmSTL - DEN

Nonstop2h 36mFrontier

Deal found 12/24

$69

Wed 1/215:42 pmSTL - DEN

1 stop24h 54mFrontier

Deal found 12/25

$70

Wed 2/253:49 pmSTL - DEN

1 stop8h 10mFrontier

Deal found 12/25

$72

Sat 2/216:41 pmSTL - DEN

1 stop10h 15mFrontier

Deal found 12/25

$77

Sat 2/214:30 pmSTL - DEN

Nonstop2h 34mUnited Airlines

Deal found 12/25

$79

Mon 2/91:40 pmSTL - DEN

Nonstop2h 36mFrontier

Deal found 12/25

$80

Find flight deals from St. Louis to Denver

Most accurate provider	eDreams 3 stars
Most trusted provider	eDreams 3 stars
Round-trip from	$83 (Cheapflightsfares)
One-way from	$54 (Cheapflightsfares)
Popular in	March
Cheapest in	October
Average price	$239
Good round-trip deal	$251 or less
Good one-way deal	$140 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. 9% potential increase in price ($24 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 4% potential price decrease ($10 potential savings vs. average RT price).

Search Deals

Average for round-trip flights in December 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

Fly from

Fly to

Route

Depart

Return

Price

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sat 1/24

6:05 pm-7:30 pm

Nonstop2h 25m

Denver Intl

Mon 1/26

7:00 am-10:15 am

Nonstop2h 15m

$177

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Fri 1/2

8:42 pm-8:55 am

1 stop13h 13m

Denver Intl

Wed 1/7

6:33 pm-10:33 pm

1 stop27h 00m

$187

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Fri 1/23

9:59 am-3:38 pm

1 stop6h 39m

Denver Intl

Fri 1/23

12:30 am-8:53 am

1 stop7h 23m

$197

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Mon 1/12

8:45 am-10:21 am

Nonstop2h 36m

Denver Intl

Wed 1/14

10:10 am-1:16 pm

Nonstop2h 06m

$217

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 2/18

8:17 pm-7:39 am

1 stop12h 22m

Denver Intl

Sun 2/22

3:08 pm-6:36 pm

2 stops26h 28m

$219

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sat 1/3

7:43 pm-9:15 pm

Nonstop2h 32m

Denver Intl

Sat 1/10

6:50 am-10:02 am

Nonstop2h 12m

$228

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Fri 2/6

6:00 pm-7:38 pm

Nonstop2h 38m

Denver Intl

Tue 2/10

10:10 am-1:16 pm

Nonstop2h 06m

$237

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Fri 1/16

6:10 am-10:31 am

1 stop5h 21m

Denver Intl

Wed 1/21

2:42 pm-11:37 pm

1 stop7h 55m

$237

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sat 1/10

4:15 pm-5:53 pm

Nonstop2h 38m

Denver Intl

Wed 1/14

10:10 am-1:16 pm

Nonstop2h 06m

$257

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Fri 2/20

6:00 pm-7:34 pm

Nonstop2h 34m

Denver Intl

Sun 3/1

5:25 pm-8:26 pm

Nonstop2h 01m

$262

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/23

Showing 1-10 of 23 results

Compare providers for flights from St. Louis to Denver

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 December.

Provider	Price Accuracy	Trust Score*
Expedia	Price Accuracy2 stars	Trust Score*3 stars
FlightHub	Price Accuracy3 stars	Trust Score*1 star
eDreams	Price Accuracy3 stars	Trust Score*3 stars
Cheapflightsfares	Price Accuracy3 stars	Trust Score*2 stars
JustAirTicket	Price Accuracy-	Trust Score*1 star
CheapTicketsDeal	Price Accuracy3 stars	Trust Score*3 stars
Cheapfaremart	Price Accuracy-	Trust Score*1 star

*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 eDreams to be most consistent on Cheapflights vs. eDreams Users can find the same prices on St. Louis-Denver flight deals on Cheapflights vs. eDreams >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 eDreams the most. eDreams 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.

Cheapflights Insights

Everything you need to know about your flight from St. Louis to Denver

Prices

Airlines

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

Booking 75 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, February is the cheapest month in which you can book a flight from St. Louis to Denver (average of $36). Flying from St. Louis to Denver in July is currently the most expensive (average of $104). 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?

It’s optimal to fly from St. Louis to Denver in the evening. By choosing this option you can save up to 62% on the cost of your flight, compared to a flight at noon.

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

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 at noon flights should be avoided if possible as fares are typically the most expensive at this time.

The best insider tips for St. Louis to Denver flights

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.

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.

Airports

STL

Security at STL is generally quick, taking 5 to 10 minutes during off-peak times. Check real-time wait times online before heading to the airport.

DEN

Take the A Line train from DEN to Union Station in 37 minutes. It runs every 15 minutes and is a cost-effective way to reach downtown Denver.

Our travel experts

Marisa Garcia

Expert on Frontier

Harriet Baskas

Expert on United Airlines

Taryn White

Expert on STL

Emily Zemler

Expert on DEN

Reviews of airlines servicing Denver

Get a feel of what it's like to fly with Southwest, Delta, and United Airlines from St. Louis to Denver 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

4,258 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

Southwest

8.0

Very good

4,258 reviews

Southwest

8.0

Very good

4,258 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

Delta

7.9

Good

8,013 reviews

Southwest

8.0

Very good

4,258 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

United Airlines

7.4

Good

9,115 reviews

Southwest

8.0

Very good

4,258 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

American Airlines

7.2

Good

11,062 reviews

Southwest

8.0

Very good

4,258 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

Frontier

5.8

Fair

3,070 reviews

Southwest

8.0

Very good

4,258 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

Related info for your journey

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 5 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 174 times in the past calendar month.
How long is the flight from St. Louis to Denver?
Departing from St. Louis to Denver will take you 2h 25m. Airlines will cover a distance of 767 mi. Both multi-stop and nonstop flights can be found to your destination and back.
What are the cheapest airlines flying from St. Louis to Denver round-trip?
Frontier, at $46, was found to be the cheapest airline from St. Louis to Denver.Alternate airlines to your destination round-trip include Delta and United Airlines. Users have found that Frontier is 80% 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 $32 on Frontier. Other airlines that offer cheap prices include Southwest from $78 and United Airlines from $89 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 SkyWest Airlines (100%), Frontier (91%) or Air Canada (79%) 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 $1,098, our data indicates the cheapest price to be $76. The most popular route (Lambert-St Louis - Denver Intl), is priced around $116.
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, February is the cheapest month in which you can book a flight from St. Louis to Denver (average of $36). Flying from St. Louis to Denver in July is currently the most expensive (average of $104). 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

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Other flights to Denver

Top 5 airlines flying from St. Louis to Denver

Airline	Cheapest	Average	Flexibility	On-time
Frontier	Cheapest$50	Average$126	FlexibilityNo cancel fee	On-time62%
Delta	Cheapest$128	Average$326	FlexibilityNo cancel fee	On-timeN/A
United Airlines	Cheapest$158	Average$315	FlexibilityNo cancel fee	On-time69%
Southwest	Cheapest$176	Average$296	FlexibilityNo cancel fee	On-time63%
American Airlines	Cheapest$201	Average$261	FlexibilityNo cancel fee	On-time71%

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$54+ 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 1/9. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from St. Louis to Denver with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Cheapflights Tip: The best prices from Lambert-St Louis to Denver Intl are usually found in October or January, booked 75 days in advance, depart on a Wednesday or Friday and return on a Friday

Cheap flight deals from St. Louis to Denver

Cheapest flights from St. Louis to DenverExplore 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 December 25, 2025.

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 December 25, 2025.

Find flight deals from St. Louis to Denver

Most accurate provider

Most trusted provider

Round-trip from

One-way from

Popular in

Cheapest in

Average price

Good round-trip deal

Good one-way deal

Cheapflights Fare Finder

Use the filters below to find and compare flights from St. Louis to Denver that are best for you.

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 December.

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.

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?

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

What is the cheapest time of day to fly from STL to DEN?

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

Weekly flight availability from St. Louis to Denver

The best insider tips for St. Louis to Denver flights

AI-powered summary based on content written by travel experts. AI can make mistakes.

Cheapflights partnered with top experts to bring you the best recommendations for your St. Louis to Denver trip

Airlines

Frontier

United Airlines

Airports

STL

DEN

Our travel experts

Reviews of airlines servicing Denver

Get a feel of what it's like to fly with Southwest, Delta, and United Airlines from St. Louis to Denver by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.

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?

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

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

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

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Top 5 airlines flying from St. Louis to Denver

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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 December 25, 2025.