What is the cheapest airline that flies from Lambert-St Louis to Denver Intl?

Frontier, Southwest, and American Airlines are the most popular carriers operating from Lambert-St Louis to Denver Intl

How many flights depart from St. Louis to Denver on average per day?

As of August 2025, there are 12 flights per day flying from St. Louis to Denver. The most common time of day flights depart is 5:00AM, with 42% of flights taking off in the afternoon.

What airlines fly to Denver?

Frontier, Southwest and United Airlines are the top three most popular airlines that fly to Denver from St. Louis according to our data. Frontier is the first choice among our users, with 45% of people opting to fly with this airline when traveling to Denver. Keep in mind that there are 5 different airlines that fly to Denver on a routine basis, so you have a few additional options to choose from.

How many flights depart from St. Louis to Denver on average per week?

84 flights are operational weekly from St. Louis to Denver as of August 2025. The most popular departure day for this route is Wed, with 19% of flights per week taking off on this day.

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?

As of August 2025, there are 5 operators available to choose from 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.

$39 Cheap Flights from St. Louis to Denver (STL-DEN) in 2025

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Find the cheapest flights from St. Louis to Denver (STL-DEN)

Round-trip

One-way

Last minute

Direct

Cheap round-trip flights

7:55 pm - 9:20 pmSTL-DEN

2h 25mnonstop

6:00 am - 9:06 amDEN-STL

2h 06mnonstop

$73Frontier

Find Deal

Thu, Sep 11 - Mon, Sep 15

7:55 pm - 9:20 pmSTL-DEN

2h 25mnonstop

6:00 am - 9:06 amDEN-STL

2h 06mnonstop

$74Frontier

Find Deal

Sun, Sep 21 - Wed, Sep 24

7:54 pm - 9:23 pmSTL-DEN

2h 29mnonstop

6:00 am - 9:06 amDEN-STL

2h 06mnonstop

$76Frontier

Find Deal

Tue, Sep 2 - Sun, Sep 7

7:55 pm - 9:20 pmSTL-DEN

2h 25mnonstop

6:00 am - 9:06 amDEN-STL

2h 06mnonstop

$77Frontier

Find Deal

Fri, Sep 19 - Sun, Sep 21

7:55 pm - 9:20 pmSTL-DEN

2h 25mnonstop

6:00 am - 9:06 amDEN-STL

2h 06mnonstop

$86Frontier

Find Deal

Wed, Sep 17 - Wed, Sep 24

7:55 pm - 9:20 pmSTL-DEN

2h 25mnonstop

6:00 am - 9:06 amDEN-STL

2h 06mnonstop

$88Frontier

Find Deal

Tue, Sep 23 - Tue, Sep 30

7:55 pm - 9:20 pmSTL-DEN

2h 25mnonstop

6:00 am - 9:06 amDEN-STL

2h 06mnonstop

$92Frontier

Find Deal

Fri, Sep 12 - Tue, Sep 16

7:55 pm - 9:20 pmSTL-DEN

2h 25mnonstop

6:00 am - 9:06 amDEN-STL

2h 06mnonstop

$93Frontier

Find Deal

Fri, Sep 12 - Tue, Sep 16

7:55 pm - 9:20 pmSTL-DEN

2h 25mnonstop

6:00 am - 9:06 amDEN-STL

2h 06mnonstop

$94Frontier

Find Deal

Sun, Sep 21 - Wed, Sep 24

8:45 pm - 10:05 pmSTL-DEN

2h 20mnonstop

1:15 pm - 5:50 pmDEN-STL

3h 35m1 stop

$145Southwest

Find Deal

Wed, Sep 10 - Wed, Sep 17

Frontier flights from St. Louis to Denver

Our best Frontier deals on St. Louis to Denver flight tickets

Frontier

Sep 11

STL7:55 pmLambert-St Louis

2h 25m

DEN9:20 pmDenver Intl

Sep 15

DEN6:00 amDenver Intl

2h 06m

STL9:06 amLambert-St Louis

$73

Find similar

Frontier

Sep 21

STL7:55 pmLambert-St Louis

2h 25m

DEN9:20 pmDenver Intl

Sep 24

DEN6:00 amDenver Intl

2h 06m

STL9:06 amLambert-St Louis

$74

Find similar

Frontier

Sep 2

STL7:54 pmLambert-St Louis

2h 29m

DEN9:23 pmDenver Intl

Sep 7

DEN6:00 amDenver Intl

2h 06m

STL9:06 amLambert-St Louis

$76

Find similar

Fly from

Fly to

Route

Depart

Return

Price

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Thu 9/11

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Mon 9/15

6:00 am-9:06 am

Nonstop2h 06m

$73

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sun 9/21

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Wed 9/24

6:00 am-9:06 am

Nonstop2h 06m

$74

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Tue 9/2

7:54 pm-9:23 pm

Nonstop2h 29m

Denver Intl

Sun 9/7

6:00 am-9:06 am

Nonstop2h 06m

$76

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Fri 9/19

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Sun 9/21

6:00 am-9:06 am

Nonstop2h 06m

$77

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 9/17

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Wed 9/24

6:00 am-9:06 am

Nonstop2h 06m

$86

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Tue 9/23

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Tue 9/30

6:00 am-9:06 am

Nonstop2h 06m

$88

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Fri 9/12

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Tue 9/16

6:00 am-9:06 am

Nonstop2h 06m

$92

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Fri 9/12

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Tue 9/16

6:00 am-9:06 am

Nonstop2h 06m

$93

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Sun 9/21

7:55 pm-9:20 pm

Nonstop2h 25m

Denver Intl

Wed 9/24

6:00 am-9:06 am

Nonstop2h 06m

$94

St. LouisDenver

STL - DEN

STLDEN

Lambert-St Louis

Wed 9/10

8:45 pm-10:05 pm

Nonstop2h 20m

Denver Intl

Wed 9/17

1:15 pm-5:50 pm

1 stop3h 35m

$145

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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

Prices

Airlines

Other information

What is the cheapest month to fly to Denver?

The cheapest month to fly to Denver from St. Louis is in September. Flight prices, which tend to average around $158, are often lower during this time because this is during the off-season. If you don’t want to visit Denver in September, then you should wait until October to fly from St. Louis, when ticket prices are also cheap, with an average price of $164.

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 $301. 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 $422.

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 $182. Flights in the morning are often more expensive with an average ticket price of $462.

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 $218 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 $160 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 August 2025, prices for St. Louis to Denver flights are approximately 44% cheaper 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

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 20m 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?
As of August 2025, there are 5 operators available to choose from 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?
Based on momondo bookings for flights between St. Louis and Denver, the leading plane model is Boeing 737-800 Passenger/BBJ2 (winglets), making up 16.92% of the total bookings. Other popular models include Boeing 737 MAX 8 with 16.76%, Airbus A320-100/200 with 11.61%, and Boeing 737-700 Passenger/BBJ1 (winglets) with 11.45%.
What is the most popular airline from St. Louis to Denver?
momondo data reveals that the most frequently booked airline on the route from St. Louis to Denver is Frontier, representing 49% of all bookings. The subsequent popular airlines are United Airlines at 25%, Southwest at 25%, and Delta at 1%.

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
Frontier	PriceFrom $46	Free Cancellation	Rating 5.8 3,219 reviews	Search Frontier flights
Delta	PriceFrom $128	Free Cancellation	Rating 8.0 7,980 reviews	Search Delta flights
United Airlines	PriceFrom $154	Free Cancellation	Rating 7.4 8,916 reviews	Search United Airlines flights
Southwest	PriceFrom $177	Free Cancellation	Rating 8.0 4,244 reviews	Search Southwest flights
American Airlines	PriceFrom $201	Free Cancellation	Rating 7.2 10,000 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 36 flights on this route every week with an average price of $293. Southwest is rated 8.0/10 by our users.
United Airlines Flights From St. Louis to Denver
Across 8,916 United Airlines reviews on momondo, the average score is 7.4/10. United Airlines flies from St. Louis to Denver about 21 times each week, with ticket deals ranging from $154 to $314. Price data is based on momondo searches in the last 72 hours.

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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.

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Cheap flights from St. Louis to Denver from $39

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 9/4. 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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Find the cheapest flights from St. Louis to Denver (STL-DEN)

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Frontier flights from St. Louis to Denver

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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?

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 $301. 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 $422.

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 $182. Flights in the morning are often more expensive with an average ticket price of $462.

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?

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 August 2025, prices for St. Louis to Denver flights are approximately 44% cheaper when compared to flights at the same time last year.

What is the cheapest airline that flies from Lambert-St Louis to Denver Intl?

Frontier, Southwest, and American Airlines are the most popular carriers operating from Lambert-St Louis to Denver Intl

What airlines fly to Denver?

How many flights depart from St. Louis to Denver on average per day?

As of August 2025, there are 12 flights per day flying from St. Louis to Denver. The most common time of day flights depart is 5:00AM, with 42% of flights taking off in the afternoon.

How many flights depart from St. Louis to Denver on average per week?

84 flights are operational weekly from St. Louis to Denver as of August 2025. The most popular departure day for this route is Wed, with 19% of flights per week taking off on this day.

When to book flights from St. Louis to Denver

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

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

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?

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

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

Southwest Flights From St. Louis to Denver

United Airlines Flights From St. Louis to Denver

Traveling to a place near Denver?

Why use momondo?

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

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

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

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

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.

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.

Find better results for your trip to the United States

Airports servicing Colorado