Find Cheap Flights from Lambert-St Louis to Denver International (STL - DEN)

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Fri 12/15
Fri 12/22
Any month
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Good to Know

Low Season:
April
Best time to beat the crowds
2%
expected price decrease
High Season:
December
Most popular time to fly
4%
expected price increase
Average Price:
$218
(avg. price over the last 2 weeks)
Good Deal:
$142
or less (round trip)

When to Book Flights from Lambert-St Louis to Denver International

Average price per month
Flight prices as travel date approaches
-1 day
-2 days

Top tips for Finding a Cheap Flight

Looking for a cheap flight? 25% of our users found flights on this route for $142 or less.
The cheapest flight from Lambert-St Louis to Denver International was found 35 days before departure, on average.
Book at least 2 weeks before departure in order to get a below-average price.
Morning departure is around 12% cheaper than an evening flight, on average*.
*Average of the lowest prices shown in KAYAK’s search results for departures within the next 30 days

FAQs for Booking Lambert-St Louis to Denver International Flights

How long does a flight from Lambert-St Louis to Denver International take?
An average nonstop flight takes 2h 26m, covering a distance of 768 miles.
How many flights are there between Lambert-St Louis and Denver International?
There are 336 (nonstop) flights between Lambert-St Louis and Denver International per week, averaging 50 per day.
Which airlines provide the cheapest flights from Lambert-St Louis to Denver International?
In the past 3 days, the cheapest round-trip tickets were found on United ($69), Multiple Airlines ($70) and Frontier ($71).
Do I need a passport to fly between Lambert-St Louis and Denver International?
No.
Which airlines fly most frequently between Lambert-St Louis and Denver International?
Air Canada (16 times daily), United (16 times daily), Southwest (12 times daily) are the most frequent flyers on this route.
What’s the cheapest day of the week to fly Lambert-St Louis to Denver International?
For Lambert-St Louis to Denver International, Saturday is the cheapest day to fly on average and Wednesday is the most expensive. Flying from Denver International back to Lambert-St Louis, the best deals are generally found on Wednesday, with Saturday being the most expensive.

Book cheap flights from Lambert-St Louis to Denver International (round-trip)

Airports
Origin
St. Louis
$69
only
$69
Destination
Denver
$69
only
$69
Sat, Jan 20
STL
DEN
2h 29m
Wed, Jan 24
DEN
STL
2h 03m
Trip: 5 days
7.4GoodShow reviews
Overall 7.4 Good
Based on 35 reviews
Overall
7.2
Boarding
7.4
Comfort
6.9
Crew
7.7
Entertainment
6.5
Food
6.4
STL
DEN
Excellent 10.0

Smooth and positive communication.

STL
DEN
Good 6.6

Friendly few, clean plane, and on time

It was way too hot on the plane. I understand it's hard to find a happy medium with people on temperature but this flight was too warm, especially with people traveling with winter wear on.

STL
DEN
Good 7.3

He was the epitome of the Friendly Skies. Chatted with whom wished to chat was quite near those that wanted to snooze on this early morning flight.

STL
DEN
Excellent 10.0

Wifi on flight

STL
DEN
Excellent 8.6

Little more time between flights would be nice

Tue, Jan 9
STL
DEN
2h 29m
Wed, Jan 17
DEN
STL
2h 03m
Trip: 9 days
Overall 0.0 Poor
Based on 0 reviews
Sat, Feb 10
STL
DEN
2h 37m
Wed, Feb 14
DEN
STL
1h 59m
Trip: 5 days
5.7OkayShow reviews
Overall 5.7 Okay
Based on 150 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
STL
DEN
Excellent 8.0

On time departure and crew was friendly

STL
DEN
Excellent 8.0

The flight was on time. The landing smooth.

The whole cost. Pay for ticket. Pay for seat assignments. Pay for luggage. Pay $3.00 for a soda! Then the f.a. walk down the isle asking if we want a credit card. Then we're asked to clean our seats for next flight to save time for the crew to clean up. All the hidden costs, ridiculous! The seats uncomfortable.

STL
DEN
Good 6.0

Frontier's new seats and fees.

STL
DEN
Mediocre 2.0

Nothing about the experience

I didn't like the fact we never got to board to plane and the flight left with four empty seats and we could have got on our flight but our vacation was ruined

STL
DEN
Excellent 10.0

Ease

Wed, Jan 24
STL
DEN
2h 36m
Sat, Jan 27
DEN
STL
2h 03m
Trip: 4 days
7.4GoodShow reviews
Overall 7.4 Good
Based on 35 reviews
Overall
7.2
Boarding
7.4
Comfort
6.9
Crew
7.7
Entertainment
6.5
Food
6.4
STL
DEN
Excellent 10.0

Smooth and positive communication.

STL
DEN
Excellent 8.6

Little more time between flights would be nice

STL
DEN
Good 6.6

Friendly few, clean plane, and on time

It was way too hot on the plane. I understand it's hard to find a happy medium with people on temperature but this flight was too warm, especially with people traveling with winter wear on.

STL
DEN
Good 6.6

The crew. Short and sweet flight.

Small seats. Bad coffee.

STL
DEN
Mediocre 2.0

My friends dad passed away and was unable to get money back to go to his funeral. Plane was a small express plane which was never mentioned. Had to check bag because overhead bins were too small. No wifi. Dad and Kid took my assigned seat.

Tue, Feb 27
STL
DEN
2h 29m
Sat, Mar 3
DEN
STL
2h 01m
Trip: 5 days
Overall 0.0 Poor
Based on 0 reviews
Sat, Mar 3
STL
DEN
2h 26m
Tue, Mar 6
DEN
STL
2h 02m
Trip: 4 days
5.7OkayShow reviews
Overall 5.7 Okay
Based on 150 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
STL
DEN
Excellent 10.0

The attendants were very helpful and friendly. The plane was incredibly clean and comfortable. I would fly frontier again!

The frontier website. Not easy to use and disk not allow me to add tsa precheck or buy my bags online.

STL
DEN
Mediocre 2.0

Weather delays happen. But Frontier left me stranded in a Denver and offered me no options other than a refund? No rebooking no hotel nothing.

STL
DEN
Excellent 10.0

Ease

STL
DEN
Excellent 10.0

It was exceptionally smooth and affordable. Very impressed with what you're doing, Frontier.

It was flawless this time. No kidding.

STL
DEN
Good 6.0

Frontier's new seats and fees.

Sat, Mar 3
STL
DEN
2h 26m
Tue, Mar 6
DEN
STL
2h 02m
Trip: 4 days
5.7OkayShow reviews
Overall 5.7 Okay
Based on 150 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
STL
DEN
Mediocre 2.0

Getting off the plane.

Missed my flight because lack of people to check people in. So slow. Waited 25 minutes. Figured I missed my flight since the board said on time. It was 2:25. Asked if I could get on 7:30 flight. Took computer 10 minutes for her to see and book. As I left, she said the 2:30 was still boarding. I said, oh, do you think I could still make it? She said the plane was still loading and running a bit late, but impossible to get on because I was booked on the 7:30 flight. I will probably not fly Frontier again. 4 hours later and $50 dollars in the hole for food and drink sitting here dreading my middle seat and no room to move for 2 hours. Then, have to pay for a Lyft to get to my car because my cousin was my ride back to her house. I sure do miss the old Frontier.

STL
DEN
Okay 4.0

The prices

Paying for a carry on Seats do not recline No complimentary beverages Flight was delayed and we rarely received updates I understand that you charge for everything in order to offer better prices, but by the time the customer pays to bring on luggage, we are paying the same price as an airline that allows baggage for free with inclusive drinks, snacks and seats that recline.

STL
DEN
Mediocre 2.0

Nothing about the experience

I didn't like the fact we never got to board to plane and the flight left with four empty seats and we could have got on our flight but our vacation was ruined

STL
DEN
Mediocre 2.0

Weather delays happen. But Frontier left me stranded in a Denver and offered me no options other than a refund? No rebooking no hotel nothing.

STL
DEN
Excellent 10.0

The attendants were very helpful and friendly. The plane was incredibly clean and comfortable. I would fly frontier again!

The frontier website. Not easy to use and disk not allow me to add tsa precheck or buy my bags online.

Tue, May 15
STL
DEN
2h 29m
Wed, May 23
DEN
STL
2h 03m
Trip: 9 days
5.7OkayShow reviews
Overall 5.7 Okay
Based on 150 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
STL
DEN
Mediocre 2.0

Weather delays happen. But Frontier left me stranded in a Denver and offered me no options other than a refund? No rebooking no hotel nothing.

STL
DEN
Excellent 10.0

Ease

STL
DEN
Mediocre 2.0

Getting off the plane.

Missed my flight because lack of people to check people in. So slow. Waited 25 minutes. Figured I missed my flight since the board said on time. It was 2:25. Asked if I could get on 7:30 flight. Took computer 10 minutes for her to see and book. As I left, she said the 2:30 was still boarding. I said, oh, do you think I could still make it? She said the plane was still loading and running a bit late, but impossible to get on because I was booked on the 7:30 flight. I will probably not fly Frontier again. 4 hours later and $50 dollars in the hole for food and drink sitting here dreading my middle seat and no room to move for 2 hours. Then, have to pay for a Lyft to get to my car because my cousin was my ride back to her house. I sure do miss the old Frontier.

STL
DEN
Okay 4.0

The prices

Paying for a carry on Seats do not recline No complimentary beverages Flight was delayed and we rarely received updates I understand that you charge for everything in order to offer better prices, but by the time the customer pays to bring on luggage, we are paying the same price as an airline that allows baggage for free with inclusive drinks, snacks and seats that recline.

STL
DEN
Good 6.0

Frontier's new seats and fees.

Tue, Apr 10
STL
DEN
2h 28m
Sat, Apr 14
DEN
STL
2h 03m
Trip: 5 days
5.7OkayShow reviews
Overall 5.7 Okay
Based on 150 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
STL
DEN
Excellent 10.0

Ease

STL
DEN
Excellent 8.0

On time departure and crew was friendly

STL
DEN
Excellent 10.0

It was exceptionally smooth and affordable. Very impressed with what you're doing, Frontier.

It was flawless this time. No kidding.

STL
DEN
Okay 4.0

The prices

Paying for a carry on Seats do not recline No complimentary beverages Flight was delayed and we rarely received updates I understand that you charge for everything in order to offer better prices, but by the time the customer pays to bring on luggage, we are paying the same price as an airline that allows baggage for free with inclusive drinks, snacks and seats that recline.

STL
DEN
Mediocre 2.0

Nothing about the experience

I didn't like the fact we never got to board to plane and the flight left with four empty seats and we could have got on our flight but our vacation was ruined

Wed, Dec 20
STL
DEN
2h 31m
Wed, Dec 27
DEN
STL
2h 13m
Trip: 8 days
Overall 0.0 Poor
Based on 0 reviews
Tue, Jan 9
STL
DEN
2h 29m
Sun, Jan 14
DEN
STL
10h 07m
Trip: 6 days
5.7OkayShow reviews
Overall 5.7 Okay
Based on 150 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
STL
DEN
Excellent 8.0

Friendly staff.

Unaware of check luggage cut off

STL
DEN
Excellent 10.0

The attendants were very helpful and friendly. The plane was incredibly clean and comfortable. I would fly frontier again!

The frontier website. Not easy to use and disk not allow me to add tsa precheck or buy my bags online.

STL
DEN
Mediocre 2.0

Weather delays happen. But Frontier left me stranded in a Denver and offered me no options other than a refund? No rebooking no hotel nothing.

STL
DEN
Mediocre 2.0

Getting off the plane.

Missed my flight because lack of people to check people in. So slow. Waited 25 minutes. Figured I missed my flight since the board said on time. It was 2:25. Asked if I could get on 7:30 flight. Took computer 10 minutes for her to see and book. As I left, she said the 2:30 was still boarding. I said, oh, do you think I could still make it? She said the plane was still loading and running a bit late, but impossible to get on because I was booked on the 7:30 flight. I will probably not fly Frontier again. 4 hours later and $50 dollars in the hole for food and drink sitting here dreading my middle seat and no room to move for 2 hours. Then, have to pay for a Lyft to get to my car because my cousin was my ride back to her house. I sure do miss the old Frontier.

STL
DEN
Good 6.0

Frontier's new seats and fees.

Mon, May 7
STL
DEN
2h 29m
Mon, May 14
DEN
STL
2h 03m
Trip: 8 days
5.7OkayShow reviews
Overall 5.7 Okay
Based on 150 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
STL
DEN
Okay 4.0

The prices

Paying for a carry on Seats do not recline No complimentary beverages Flight was delayed and we rarely received updates I understand that you charge for everything in order to offer better prices, but by the time the customer pays to bring on luggage, we are paying the same price as an airline that allows baggage for free with inclusive drinks, snacks and seats that recline.

STL
DEN
Excellent 10.0

The attendants were very helpful and friendly. The plane was incredibly clean and comfortable. I would fly frontier again!

The frontier website. Not easy to use and disk not allow me to add tsa precheck or buy my bags online.

STL
DEN
Excellent 10.0

Ease

STL
DEN
Mediocre 2.0

Nothing about the experience

I didn't like the fact we never got to board to plane and the flight left with four empty seats and we could have got on our flight but our vacation was ruined

STL
DEN
Excellent 8.0

On time departure and crew was friendly

Fri, Jun 1
STL
DEN
2h 29m
Fri, Jun 8
DEN
STL
2h 03m
Trip: 8 days
5.7OkayShow reviews
Overall 5.7 Okay
Based on 150 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
STL
DEN
Mediocre 2.0

Getting off the plane.

Missed my flight because lack of people to check people in. So slow. Waited 25 minutes. Figured I missed my flight since the board said on time. It was 2:25. Asked if I could get on 7:30 flight. Took computer 10 minutes for her to see and book. As I left, she said the 2:30 was still boarding. I said, oh, do you think I could still make it? She said the plane was still loading and running a bit late, but impossible to get on because I was booked on the 7:30 flight. I will probably not fly Frontier again. 4 hours later and $50 dollars in the hole for food and drink sitting here dreading my middle seat and no room to move for 2 hours. Then, have to pay for a Lyft to get to my car because my cousin was my ride back to her house. I sure do miss the old Frontier.

STL
DEN
Mediocre 2.0

Weather delays happen. But Frontier left me stranded in a Denver and offered me no options other than a refund? No rebooking no hotel nothing.

STL
DEN
Excellent 8.0

Friendly staff.

Unaware of check luggage cut off

STL
DEN
Excellent 8.0

The flight was on time. The landing smooth.

The whole cost. Pay for ticket. Pay for seat assignments. Pay for luggage. Pay $3.00 for a soda! Then the f.a. walk down the isle asking if we want a credit card. Then we're asked to clean our seats for next flight to save time for the crew to clean up. All the hidden costs, ridiculous! The seats uncomfortable.

STL
DEN
Excellent 10.0

Ease

Thu, Jun 7
STL
DEN
2h 29m
Sun, Jun 10
DEN
STL
2h 03m
Trip: 4 days
5.7OkayShow reviews
Overall 5.7 Okay
Based on 150 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
STL
DEN
Mediocre 2.0

Nothing about the experience

I didn't like the fact we never got to board to plane and the flight left with four empty seats and we could have got on our flight but our vacation was ruined

STL
DEN
Okay 4.0

The prices

Paying for a carry on Seats do not recline No complimentary beverages Flight was delayed and we rarely received updates I understand that you charge for everything in order to offer better prices, but by the time the customer pays to bring on luggage, we are paying the same price as an airline that allows baggage for free with inclusive drinks, snacks and seats that recline.

STL
DEN
Excellent 8.0

On time departure and crew was friendly

STL
DEN
Excellent 10.0

The attendants were very helpful and friendly. The plane was incredibly clean and comfortable. I would fly frontier again!

The frontier website. Not easy to use and disk not allow me to add tsa precheck or buy my bags online.

STL
DEN
Excellent 8.0

Friendly staff.

Unaware of check luggage cut off

Wed, Dec 20
STL
DEN
2h 31m
Tue, Dec 26
DEN
STL
2h 02m
Trip: 7 days
5.7OkayShow reviews
Overall 5.7 Okay
Based on 150 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
STL
DEN
Excellent 10.0

The attendants were very helpful and friendly. The plane was incredibly clean and comfortable. I would fly frontier again!

The frontier website. Not easy to use and disk not allow me to add tsa precheck or buy my bags online.

STL
DEN
Mediocre 2.0

Getting off the plane.

Missed my flight because lack of people to check people in. So slow. Waited 25 minutes. Figured I missed my flight since the board said on time. It was 2:25. Asked if I could get on 7:30 flight. Took computer 10 minutes for her to see and book. As I left, she said the 2:30 was still boarding. I said, oh, do you think I could still make it? She said the plane was still loading and running a bit late, but impossible to get on because I was booked on the 7:30 flight. I will probably not fly Frontier again. 4 hours later and $50 dollars in the hole for food and drink sitting here dreading my middle seat and no room to move for 2 hours. Then, have to pay for a Lyft to get to my car because my cousin was my ride back to her house. I sure do miss the old Frontier.

STL
DEN
Excellent 8.0

Friendly staff.

Unaware of check luggage cut off

STL
DEN
Good 6.0

Frontier's new seats and fees.

STL
DEN
Excellent 8.0

The flight was on time. The landing smooth.

The whole cost. Pay for ticket. Pay for seat assignments. Pay for luggage. Pay $3.00 for a soda! Then the f.a. walk down the isle asking if we want a credit card. Then we're asked to clean our seats for next flight to save time for the crew to clean up. All the hidden costs, ridiculous! The seats uncomfortable.

Wed, Dec 20
STL
DEN
2h 31m
Wed, Dec 27
DEN
STL
1h 59m
Trip: 8 days
5.7OkayShow reviews
Overall 5.7 Okay
Based on 150 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
STL
DEN
Excellent 10.0

The attendants were very helpful and friendly. The plane was incredibly clean and comfortable. I would fly frontier again!

The frontier website. Not easy to use and disk not allow me to add tsa precheck or buy my bags online.

STL
DEN
Okay 4.0

The prices

Paying for a carry on Seats do not recline No complimentary beverages Flight was delayed and we rarely received updates I understand that you charge for everything in order to offer better prices, but by the time the customer pays to bring on luggage, we are paying the same price as an airline that allows baggage for free with inclusive drinks, snacks and seats that recline.

STL
DEN
Mediocre 2.0

Weather delays happen. But Frontier left me stranded in a Denver and offered me no options other than a refund? No rebooking no hotel nothing.

STL
DEN
Okay 4.0

Late...Late...Real late

STL
DEN
Mediocre 2.0

Getting off the plane.

Missed my flight because lack of people to check people in. So slow. Waited 25 minutes. Figured I missed my flight since the board said on time. It was 2:25. Asked if I could get on 7:30 flight. Took computer 10 minutes for her to see and book. As I left, she said the 2:30 was still boarding. I said, oh, do you think I could still make it? She said the plane was still loading and running a bit late, but impossible to get on because I was booked on the 7:30 flight. I will probably not fly Frontier again. 4 hours later and $50 dollars in the hole for food and drink sitting here dreading my middle seat and no room to move for 2 hours. Then, have to pay for a Lyft to get to my car because my cousin was my ride back to her house. I sure do miss the old Frontier.

Show more results
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Prices are per person and are for e–tickets and include all taxes & fees in USD.

We attempt to get accurate prices, however, prices are not guaranteed.

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The fares displayed include all taxes and fees for economy class travel and were found by the provider in the last 72 hours. Seats are limited and may not be available on all flights and days. Fares are subject to change and may not be available on all flights or dates of travel. Some carriers charge additional fees for extra checked bags. Please check the carriers' sites.