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Cheap flights from St. Louis to Denver from $79

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 7/1. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
1 adult, Economy, 0 bags

Discover deals from 900+ travel sites with momondo.

Find the cheapest flights from St. Louis to Denver

Cheap round-trip flights

Enter your travel dates to find the best prices.
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
Frontier Logo
4:12 pm - 7:23 pm
DEN
-
STL
2h 11mnonstop
$142Frontier
Thu, Aug 20 - Tue, Aug 25
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
Frontier Logo
4:10 pm - 7:23 pm
DEN
-
STL
2h 13mnonstop
$143Frontier
Wed, Jul 1 - Wed, Jul 8
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
Frontier Logo
9:25 pm - 2:48 pm
DEN
-
STL
16h 23m
1 stop
$145Frontier
Mon, Aug 17 - Tue, Aug 18
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
Frontier Logo
4:10 pm - 7:23 pm
DEN
-
STL
2h 13mnonstop
$147Frontier
Wed, Aug 5 - Tue, Aug 11
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
Frontier Logo
4:12 pm - 7:23 pm
DEN
-
STL
2h 11mnonstop
$150Frontier
Wed, Sep 2 - Sat, Sep 5
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
Frontier Logo
4:12 pm - 7:23 pm
DEN
-
STL
2h 11mnonstop
$151Frontier
Wed, Aug 26 - Wed, Sep 2
Frontier Logo
3:41 pm - 10:55 pm
STL
-
DEN
8h 14m
1 stop
Frontier Logo
4:10 pm - 7:23 pm
DEN
-
STL
2h 13mnonstop
$152Frontier
Tue, Aug 4 - Tue, Aug 11
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
Frontier Logo
4:10 pm - 7:23 pm
DEN
-
STL
2h 13mnonstop
$153Frontier
Tue, Jul 21 - Sat, Jul 25
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
Frontier Logo
4:10 pm - 7:23 pm
DEN
-
STL
2h 13mnonstop
$154Frontier
Mon, Aug 10 - Thu, Aug 13
Frontier Logo
8:08 pm - 9:44 pm
STL
-
DEN
2h 36mnonstop
Frontier Logo
4:10 pm - 7:23 pm
DEN
-
STL
2h 13mnonstop
$156Frontier
Sat, Aug 8 - Mon, Aug 17

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Frontier flights from St. Louis to Denver

Our best Frontier deals on St. Louis to Denver flight tickets
Frontier
Aug 20
STL8:08 pmLambert-St Louis
2h 36m
DEN9:44 pmDenver Intl
Aug 25
DEN4:12 pmDenver Intl
2h 11m
STL7:23 pmLambert-St Louis
$142
Frontier
Jul 1
STL8:08 pmLambert-St Louis
2h 36m
DEN9:44 pmDenver Intl
Jul 8
DEN4:10 pmDenver Intl
2h 13m
STL7:23 pmLambert-St Louis
$143
Frontier
Aug 17
STL8:08 pmLambert-St Louis
2h 36m
DEN9:44 pmDenver Intl
Aug 18
DEN9:25 pmDenver Intl
16h 23m
1 stop
STL2:48 pmLambert-St Louis
$145

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 June 11, 2026.
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

Cheapest round-trip
Quickest round-trip

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Thu 8/20

8:08 pm-9:44 pm

Nonstop2h 36m

Denver Intl

Tue 8/25

4:12 pm-7:23 pm

Nonstop2h 11m

$142

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 7/1

8:08 pm-9:44 pm

Nonstop2h 36m

Denver Intl

Wed 7/8

4:10 pm-7:23 pm

Nonstop2h 13m

$143

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Mon 8/17

8:08 pm-9:44 pm

Nonstop2h 36m

Denver Intl

Tue 8/18

9:25 pm-2:48 pm

1 stop16h 23m

$145

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 8/5

8:08 pm-9:44 pm

Nonstop2h 36m

Denver Intl

Tue 8/11

4:10 pm-7:23 pm

Nonstop2h 13m

$147

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 9/2

8:08 pm-9:44 pm

Nonstop2h 36m

Denver Intl

Sat 9/5

4:12 pm-7:23 pm

Nonstop2h 11m

$150

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 8/26

8:08 pm-9:44 pm

Nonstop2h 36m

Denver Intl

Wed 9/2

4:12 pm-7:23 pm

Nonstop2h 11m

$151

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Tue 8/4

3:41 pm-10:55 pm

1 stop8h 14m

Denver Intl

Tue 8/11

4:10 pm-7:23 pm

Nonstop2h 13m

$152

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Tue 7/21

8:08 pm-9:44 pm

Nonstop2h 36m

Denver Intl

Sat 7/25

4:10 pm-7:23 pm

Nonstop2h 13m

$153

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Mon 8/10

8:08 pm-9:44 pm

Nonstop2h 36m

Denver Intl

Thu 8/13

4:10 pm-7:23 pm

Nonstop2h 13m

$154

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sat 8/8

8:08 pm-9:44 pm

Nonstop2h 36m

Denver Intl

Mon 8/17

4:10 pm-7:23 pm

Nonstop2h 13m

$156

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 typical price of a round-trip flight between St. Louis and Denver?

What is the cheapest month to fly to Denver?

The cheapest month to fly to Denver from St. Louis is in October. Flight prices, which tend to average around $175, are often lower during this time because this is during the off-season. If you don’t want to visit Denver in October, then you should wait until September to fly from St. Louis, when ticket prices are also cheap, with an average price of $187.

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 $310. 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 $421.

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 $204. Flights in the morning are often more expensive with an average ticket price of $433.

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 from St. Louis 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 $241 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 $180 on momondo.

What cabin class options are available on St. Louis to Denver flights?

There are 4 cabin classes available to choose from on St. Louis to Denver 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 June 2026, prices for St. Louis to Denver flights are approximately 222% 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

$167

Fastest flight time

2h 15m

Direct flights

Every day

Airports in Denver

1 airport
The best one-way flight to Denver from St. Louis in the past 72 hours is $167. The best round-trip flight deal from St. Louis to Denver found on momondo in the last 72 hours is $301.
The fastest flight from St. Louis to Denver takes 2h 15m
Direct flights go from St. Louis to Denver every day.
There is 1 airport in Denver. From St. Louis there are direct flights to Denver Intl (DEN).
Search flight deals

Frequently asked questions about flying from St. Louis to Denver

  • 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 15m 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 $56Free CancellationRating
5.6
2,895 reviews
Search Frontier flights
SouthwestPriceFrom $163Free CancellationRating
7.9
4,234 reviews
Search Southwest flights
United AirlinesPriceFrom $170Free CancellationRating
7.4
9,809 reviews
Search United Airlines flights
DeltaPriceFrom $178Free CancellationRating
7.9
8,399 reviews
Search Delta flights

  • Southwest Flights From St. Louis to Denver

    The lowest priced Southwest flight from St. Louis to Denver from the last 72 hours was $163. Generally, Southwest has 35 flights on this route every week with an average price of $326. Southwest is rated 7.9/10 by our users.

  • United Airlines Flights From St. Louis to Denver

    Across 9,809 United Airlines reviews on momondo, the average score is 7.4/10. United Airlines flies from St. Louis to Denver about 23 times each week, with ticket deals ranging from $170 to $330. 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
Manitou Springs
Boulder
Longmont
Greeley
Westminster
Lakewood
Keystone
Cripple Creek
Thornton
Englewood
Centennial
Frisco
Littleton
Winter Park
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

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