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Cheap flights from St. Louis to Denver from $41

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from St. Louis to Denver departing on 12/20. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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0 bags

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Cheap round-trip flights

Enter your travel dates to find the best prices.
Frontier Logo
7:45 pm - 9:13 pmSTL-DEN
2h 28mnonstop
Frontier Logo
6:50 am - 10:02 amDEN-STL
2h 12mnonstop
$77Frontier
Find Deal
Wed, Nov 19 - Sat, Nov 29
Frontier Logo
7:45 pm - 9:13 pmSTL-DEN
2h 28mnonstop
Frontier Logo
6:50 am - 10:02 amDEN-STL
2h 12mnonstop
$78Frontier
Find Deal
Wed, Nov 19 - Mon, Nov 24
Frontier Logo
7:43 pm - 9:15 pmSTL-DEN
2h 32mnonstop
Frontier Logo
12:59 am - 9:47 amDEN-STL
7h 48m1 stop
$79Frontier
Find Deal
Wed, Jan 7 - Wed, Jan 7
Frontier Logo
7:43 pm - 9:15 pmSTL-DEN
2h 32mnonstop
Frontier Logo
7:05 am - 10:14 amDEN-STL
2h 09mnonstop
$83Frontier
Find Deal
Mon, Dec 8 - Wed, Dec 10
Frontier Logo
7:43 pm - 9:15 pmSTL-DEN
2h 32mnonstop
Frontier Logo
10:37 pm - 12:12 pmDEN-STL
12h 35m1 stop
$84Frontier
Find Deal
Sat, Dec 6 - Sat, Dec 13
Frontier Logo
7:43 pm - 9:15 pmSTL-DEN
2h 32mnonstop
Frontier Logo
11:59 pm - 10:33 pmDEN-STL
21h 34m1 stop
$85Frontier
Find Deal
Sat, Dec 6 - Mon, Dec 8
Frontier Logo
7:43 pm - 9:15 pmSTL-DEN
2h 32mnonstop
Frontier Logo
7:05 am - 10:14 amDEN-STL
2h 09mnonstop
$92Frontier
Find Deal
Wed, Dec 10 - Fri, Dec 12
Frontier Logo
7:43 pm - 9:15 pmSTL-DEN
2h 32mnonstop
Frontier Logo
7:05 am - 10:14 amDEN-STL
2h 09mnonstop
$93Frontier
Find Deal
Sat, Dec 13 - Mon, Dec 15
Frontier Logo
7:43 pm - 9:17 pmSTL-DEN
2h 34mnonstop
Frontier Logo
6:50 am - 10:02 amDEN-STL
2h 12mnonstop
$97Frontier
Find Deal
Wed, Nov 26 - Sat, Nov 29
Frontier Logo
7:43 pm - 9:17 pmSTL-DEN
2h 34mnonstop
Frontier Logo
6:50 am - 10:02 amDEN-STL
2h 12mnonstop
$98Frontier
Find Deal
Fri, Nov 21 - Mon, Nov 24

Frontier flights from St. Louis to Denver

Our best Frontier deals on St. Louis to Denver flight tickets
Frontier
Nov 19
STL7:45 pmLambert-St Louis
2h 28m
DEN9:13 pmDenver Intl
Nov 29
DEN6:50 amDenver Intl
2h 12m
STL10:02 amLambert-St Louis
$77
Find similar
Frontier
Nov 19
STL7:45 pmLambert-St Louis
2h 28m
DEN9:13 pmDenver Intl
Nov 24
DEN6:50 amDenver Intl
2h 12m
STL10:02 amLambert-St Louis
$78
Find similar
Frontier
Jan 7
STL7:43 pmLambert-St Louis
2h 32m
DEN9:15 pmDenver Intl
Jan 7
DEN12:59 amDenver Intl
7h 48m
1 stop
STL9:47 amLambert-St Louis
$79
Find similar

momondo 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, momondo users made 832,500 searches. Data last updated November 6, 2025.
Use the filters below to find and compare flights from St. Louis to Denver that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 11/19

7:45 pm-9:13 pm

Nonstop2h 28m

Denver Intl

Sat 11/29

6:50 am-10:02 am

Nonstop2h 12m

$77

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 11/19

7:45 pm-9:13 pm

Nonstop2h 28m

Denver Intl

Mon 11/24

6:50 am-10:02 am

Nonstop2h 12m

$78

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 1/7

7:43 pm-9:15 pm

Nonstop2h 32m

Denver Intl

Wed 1/7

12:59 am-9:47 am

1 stop7h 48m

$79

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Mon 12/8

7:43 pm-9:15 pm

Nonstop2h 32m

Denver Intl

Wed 12/10

7:05 am-10:14 am

Nonstop2h 09m

$83

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sat 12/6

7:43 pm-9:15 pm

Nonstop2h 32m

Denver Intl

Sat 12/13

10:37 pm-12:12 pm

1 stop12h 35m

$84

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sat 12/6

7:43 pm-9:15 pm

Nonstop2h 32m

Denver Intl

Mon 12/8

11:59 pm-10:33 pm

1 stop21h 34m

$85

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 12/10

7:43 pm-9:15 pm

Nonstop2h 32m

Denver Intl

Fri 12/12

7:05 am-10:14 am

Nonstop2h 09m

$92

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sat 12/13

7:43 pm-9:15 pm

Nonstop2h 32m

Denver Intl

Mon 12/15

7:05 am-10:14 am

Nonstop2h 09m

$93

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 11/26

7:43 pm-9:17 pm

Nonstop2h 34m

Denver Intl

Sat 11/29

6:50 am-10:02 am

Nonstop2h 12m

$97

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Fri 11/21

7:43 pm-9:17 pm

Nonstop2h 34m

Denver Intl

Mon 11/24

6:50 am-10:02 am

Nonstop2h 12m

$98

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to Denver from

How to get the cheapest flight ticket from St. Louis to Denver

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest month to fly to Denver?

The cheapest month to fly to Denver from St. Louis is in November. Flight prices, which tend to average around $169, are often lower during this time because this is during the off-season. If you don’t want to visit Denver in November, then you should wait until October to fly from St. Louis, when ticket prices are also cheap, with an average price of $177.

What is the cheapest day to depart on your flight to Denver?

The cheapest day to depart on your flight to Denver is on a Wednesday when prices can be found for as low as $296. This is often the case because there is less demand to fly during this day of the week. The most expensive day to fly to Denver is Sunday, with ticket prices averaging around $419.

What is the cheapest time of day to depart on your flight to Denver?

The cheapest time of day to fly to Denver is in the evening when flights can be purchased for as low as $175. Flights at noon are often more expensive with an average ticket price of $465.

What is the cheapest Lambert-St Louis to Denver Intl flight route?

Fly from Lambert-St Louis to Denver Intl for the best Lambert-St Louis - Denver Intl flight prices

How far in advance should I book a flight to Denver?

You are more likely to see cheaper flights to Denver from St. Louis when booking weeks ahead of your departure date. In general, you can expect to find flights to Denver for around $223 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Denver from St. Louis for as low as $170 on momondo.

What cabin class options are available on Lambert-St Louis to Denver Intl flights?

There are 4 cabin classes available to choose from on Lambert-St Louis to Denver Intl flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

How have St. Louis to Denver flight prices changed over time?

As of November 2025, prices for St. Louis to Denver flights are approximately 0% more expensive when compared to flights at the same time last year.

When to book flights from St. Louis to Denver

Are you open to changing your travel dates? Check out the ideal times to fly from St. Louis to Denver according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap St. Louis to Denver (STL to DEN) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from St. Louis to Denver

Best Price Found

$125

Fastest flight time

2h 20m

Direct flights

Tue, Wed, Thu, Fri, Sat and Sun

Airports in Denver

1 airport
The best one-way flight to Denver from St. Louis in the past 72 hours is $125. The best round-trip flight deal from St. Louis to Denver found on momondo in the last 72 hours is $183.
The fastest flight from St. Louis to Denver takes 2h 20m
Direct flights go from St. Louis to Denver on Tuesday, Wednesday, Thursday, Friday, Saturday and Sunday. The only airline offering direct flights is United Airlines.
There is 1 airport near Denver: Denver Intl (DEN)
Search flight deals

  • How far is Lambert-St Louis to Denver Intl by plane?

    The straight-line distance from Lambert-St Louis to Denver Intl is 794.2 mi. Typically, this will take 2h 28m by plane in normal conditions.

  • When did momondo last update prices for flights from Lambert-St Louis Airport to Denver Intl Airport?

    Prices for flights from Lambert-St Louis Airport to Denver Intl Airport were last updated today.

  • How many operators does momondo search for flights from Lambert-St Louis Airport to Denver Intl Airport?

  • How old do you have to be to fly from Lambert-St Louis Airport to Denver Intl Airport?

    The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Lambert-St Louis Airport to Denver Intl Airport.

  • What documentation or ID do you need to fly to Denver Intl Airport?

    The necessary travel and health documents for your Denver Intl Airport trip may vary depending on your travel plans and individual circumstances. Generally, you should have various documents, such as a national ID card or driver's license and a passport that is valid for six months beyond your scheduled arrival date. We recommend seeking advice from your airline or a trusted third party, such as IATA.

  • What is the most popular plane model from St. Louis to Denver?

  • What is the most popular airline from St. Louis to Denver?

Best airlines flying from St. Louis to Denver

Compare and see reviews for airlines that fly from St. Louis to Denver with momondo
Airline
Rating
Free Cancellation
Price
FrontierPriceFrom $50Free CancellationRating
5.8
3,116 reviews
Search Frontier flights
DeltaPriceFrom $108Free CancellationRating
7.9
8,004 reviews
Search Delta flights
United AirlinesPriceFrom $155Free CancellationRating
7.4
9,003 reviews
Search United Airlines flights
SouthwestPriceFrom $177Free CancellationRating
8.0
4,240 reviews
Search Southwest flights
American AirlinesPriceFrom $201Free CancellationRating
7.2
11,042 reviews
Search American Airlines flights

  • Southwest Flights From St. Louis to Denver

    The lowest priced Southwest flight from St. Louis to Denver from the last 72 hours was $177. Generally, Southwest has 31 flights on this route every week with an average price of $294. Southwest is rated 8.0/10 by our users.

  • United Airlines Flights From St. Louis to Denver

    Across 9,004 United Airlines reviews on momondo, the average score is 7.4/10. United Airlines flies from St. Louis to Denver about 17 times each week, with ticket deals ranging from $155 to $316. Price data is based on momondo searches in the last 72 hours.

Traveling to a place near Denver?

Book flights to Denver if you plan to visit one of these locations
Breckenridge
Estes Park
Black Hawk
Aurora
Fort Collins
Keystone
Cripple Creek
Manitou Springs
Longmont
Boulder
Greeley
Lakewood
Thornton
Westminster
Winter Park
Copper Mountain
Silverthorne
Frisco
Centennial
Grand Lake

Why use momondo?

Why should I use momondo to find a flight deal from St. Louis to Denver?

Finding the right flight to Denver from St. Louis is quick and easy when you have a range of options in front of you, from reputable agents and recognisable airlines. Options that can then be filtered down to find the best fit. That is what momondo does. We make finding flights to Denver quick and easy, saving you time and money.

Can I find flights from St. Louis to Denver with flexible booking policies on momondo?

momondo does allow users to show only those flights to Denver from St. Louis which offer a flexible booking policy as well as other useful filters and features.

How can momondo help me find flights from St. Louis to Denver?

momondo provides multiple filters to help you find the best flight to Denver from St. Louis. Filter by price, airline, airports, cabin, aircraft, payment method, number of stops and more.

I’m not ready to book a flight from St. Louis to Denver right now. Can momondo alert me if prices change?

Of course. momondo tracks the price of St. Louis to Denver flights. All you need is a valid email address and we will do the rest; it is that quick and easy.

An easier way to manage your Denver trip

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.
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