$40 Cheap flight deals from Denver (DEN) to O'Fallon (STL)

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This Weekend's Flight Deals from Denver to O'Fallon

This weekend's flight prices found within the past 7 days, for the period specified. Prices and availability are subject to change. Additional terms apply.

Sun, Apr 5 - Thu, Apr 9
DEN
Denver Intl.
STL
Lambert-St. Louis Intl.
$209 Roundtrip, found 2 days ago
$209
Roundtrip
found 2 days ago
Select Frontier Airlines flight, departing Sun, Apr 5 from Denver Intl. to Lambert-St. Louis Intl., returning Thu, Apr 9, priced at $209 found 2 days ago

Airfares from $40 One Way, $75 Round Trip from Denver to O'Fallon

Prices starting at $75 for return flights and $40 for one-way flights to O'Fallon were the cheapest prices found within the past 7 days, for the period specified. Prices and availability are subject to change. Additional terms apply.

Sat, May 2 - Sat, May 9
DEN
Denver
STL
St. Louis
$75 Roundtrip, found 10 hours ago
$75
Roundtrip
found 10 hours ago
Select Frontier Airlines flight, departing Sat, May 2 from Denver to St. Louis, returning Sat, May 9, priced at $75 found 10 hours ago
Sat, May 9 - Mon, May 11
DEN
Denver
STL
St. Louis
$89 Roundtrip, found 4 hours ago
$89
Roundtrip
found 4 hours ago
Select Frontier Airlines flight, departing Sat, May 9 from Denver to St. Louis, returning Mon, May 11, priced at $89 found 4 hours ago
Sat, May 2 - Mon, May 4
DEN
Denver
STL
St. Louis
$90 Roundtrip, found 2 hours ago
$90
Roundtrip
found 2 hours ago
Select Frontier Airlines flight, departing Sat, May 2 from Denver to St. Louis, returning Mon, May 4, priced at $90 found 2 hours ago
Thu, Apr 16 - Mon, Apr 20
DEN
Denver
STL
St. Louis
$92 Roundtrip, found 11 hours ago
$92
Roundtrip
found 11 hours ago
Select Frontier Airlines flight, departing Thu, Apr 16 from Denver to St. Louis, returning Mon, Apr 20, priced at $92 found 11 hours ago
Sat, Apr 25 - Sat, May 2
DEN
Denver
STL
St. Louis
$222 Roundtrip, found 17 hours ago
$222
Roundtrip
found 17 hours ago
Select Southwest Airlines flight, departing Sat, Apr 25 from Denver to St. Louis, returning Sat, May 2, priced at $222 found 17 hours ago

O'Fallon economy flight packages

Price found within the past 48 hours. Click for updated prices.
21C Museum Hotel St Louis
4.5-star property

21C Museum Hotel St Louis

9/10 Wonderful! (1,647 reviews)

May 1 - May 4

3 night stay

Denver (DEN) to St. Louis (STL)

Frontier Airlines • Roundtrip • Coach
Price was $444, price is now $340 per person
$340
per person
found 1 day ago
The cafe that sold breakfast ran out of healthy options each morning (yogurt parfait cup/ overnight oats & quinoa $8 each) They had other plates, egg with meat, etc that looked nice fwiw. Cute gift shop in the cafe. Fashionable hotel with no real 'front desk' just a checkin counter, but volunteers were staffing a St. Louis info table in the lobby while we were there- very friendly. The bar/tapas restaurant across the lobby was fun, $$, and kitchen closed at 10 or so when our events got out so I didn't get to try it. LOVED the historic building, originally a YMCA, the handsome billiards room and the terrific tiled pool with vaulted ceiling- they don't make them like that anymore. Steam room, sauna, showers were great- bring a room towel in case the spa runs short! Open til 10:30p or 11p fyi. Art Museum on the 2nd floor is free to visitors, and had some challenging, gorgeous, funny, and thought-provoking art. Historic Campbell Mansion next door was a neat contrast and a quick peek into the high Victorian era. Glad I went, would stay again

Reviewed on Jan 14, 2026

The Wildwood Hotel
3.5-star property

The Wildwood Hotel

9.2/10 Wonderful! (1,620 reviews)

May 1 - May 4

3 night stay

Denver (DEN) to St. Louis (STL)

Frontier Airlines • Roundtrip • Coach
Save 100% on your flight
Price was $611, price is now $350 per person
$350
per person
found 1 day ago
This hotel was fantastic! Check in was easy with friendly staff, the room was beautiful and well appointed. Breakfast was advertised as a Continental, however they had hot options as well, which was great. Every staff member we saw in the hotel said hi and was friendly. I would definitely stay here again!

Reviewed on Oct 16, 2025

Hilton Garden Inn Chesterfield
3.0-star property

Hilton Garden Inn Chesterfield

8.2/10 Very Good! (799 reviews)

May 1 - May 4

3 night stay

Denver (DEN) to St. Louis (STL)

Frontier Airlines • Roundtrip • Coach
Save 100% on your flight
Price was $557, price is now $418 per person
$418
per person
found 1 day ago
Great stay great service

Reviewed on Apr 8, 2025

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More About Flying To O'Fallon from Denver

Route Information for Flights from Denver to O'Fallon

Origin Airport IATA Code
DEN
Destination Airport IATA Code
STL
Distance
Direct Flight Airlines
Earliest Flight Arrival
Latest Flight Arrival

Denver to O'Fallon

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Fare, taxes & fees: Fares include all taxes and fees, except baggage fees. Rates shown reflect fares found by other Orbitz users over the past 7 days. Due to rapidly changing airline prices & seat availability, these fares may no longer be available.

Refunds/changes/cancellations: Itinerary changes, if permitted for the fare, will have a $30 service fee charged by Orbitz. Additional airline charges may apply.

Other conditions: Schedules, fares and rules are subject to change without notice. Seats are limited and may not be available on all flights/dates or in all markets. Lower fares may be available. Fares will not be honored retroactively or in exchange for any wholly/partially unused ticket. Tickets are non-transferable and non-refundable. Fare rules are provided for the selected itinerary before booking.