Nonstop flights from Ontario to Denver from $40 ONT → DEN
Ontario International Airport (ONT) → Denver International Airport (DEN)
The cheapest nonstop return found recently is $115 with Frontier Airlines, 23 Dec – 30 Dec, found 2 days ago.
Nonstop return
The cheapest nonstop return fare on each of 7 departure dates is usually $160 to $251.
Cheapest nonstop return
$115
23 Dec – 30 Dec · Frontier Airlines
Ontario International Airport (ONT) → Denver International Airport (DEN)
Leaves 6:30 a.m. · Return leaves 10:48 p.m. · 4 h 49 min of travel, both ways together
out nonstop, back nonstop
found 2 days ago
Airlines flying it nonstop on the return fares we hold: Frontier Airlines (6 departure dates), United Airlines (6 departure dates), American Airlines (3 departure dates), Southwest Airlines (3 departure dates).
On the 11 trips where we hold both on the same dates, nonstop cost a median $22 (16.1%) less than the cheapest fare with stops. Nonstop was cheaper or the same price on 7 of those 11 trips.
Every nonstop date we hold
Nonstop fares on 7 of the 12 departure dates we hold for this route.
See the chart as a table
| Dates | From | Airline | Airports | Stops | Found | |
|---|---|---|---|---|---|---|
| 21 Dec – 26 Dec | $216 | Frontier Airlines | Ontario International Airport (ONT) → Denver International Airport (DEN) | out nonstop, back nonstop | found 2 days ago | See prices for these dates |
| 23 Dec – 30 Dec | $115 | Frontier Airlines | Ontario International Airport (ONT) → Denver International Airport (DEN) | out nonstop, back nonstop | found 2 days ago | See prices for these dates |
| 28 Dec – 4 Jan 2027 | $248 | Frontier Airlines | Ontario International Airport (ONT) → Denver International Airport (DEN) | out nonstop, back nonstop | found 3 days ago | See prices for these dates |
| 29 Dec – 3 Jan 2027 | $177 | Frontier Airlines | Ontario International Airport (ONT) → Denver International Airport (DEN) | out nonstop, back nonstop | found 4 days ago | See prices for these dates |
| 22 Jan 2027 – 24 Jan 2027 | $142 | Frontier Airlines | Ontario International Airport (ONT) → Denver International Airport (DEN) | out nonstop, back nonstop | found 7 days ago | See prices for these dates |
| 11 Feb 2027 – 14 Feb 2027 | $255 | Frontier Airlines | Ontario International Airport (ONT) → Denver International Airport (DEN) | out nonstop, back nonstop | found 4 days ago | See prices for these dates |
| 8 Apr 2027 – 12 Apr 2027 | $472 | Southwest Airlines | Ontario International Airport (ONT) → Denver International Airport (DEN) | out nonstop, back nonstop | found 4 days ago | See prices for these dates |
Nonstop one-way
The cheapest nonstop one-way fare on each of 6 departure dates is usually $95 to $204.
Cheapest nonstop one-way
$40
15 Dec · Frontier Airlines
Ontario International Airport (ONT) → Denver International Airport (DEN)
Leaves 6:00 a.m. · 2 h 24 min trip
nonstop
found yesterday
Airlines flying it nonstop on the one-way fares we hold: Frontier Airlines (6 departure dates), United Airlines (1 departure date).
We hold too few one-way trips with both a nonstop fare and a fare with stops on the same dates to compare the two.
Every nonstop date we hold
Nonstop fares on 6 of the 8 departure dates we hold for this route.
See the chart as a table
| Dates | From | Airline | Airports | Stops | Found | |
|---|---|---|---|---|---|---|
| 10 Dec | $88 | Frontier Airlines | Ontario International Airport (ONT) → Denver International Airport (DEN) | nonstop | found 5 days ago | Open this trip |
| 15 Dec | $40 | Frontier Airlines | Ontario International Airport (ONT) → Denver International Airport (DEN) | nonstop | found yesterday | Open this trip |
| 27 Dec | $206 | Frontier Airlines | Ontario International Airport (ONT) → Denver International Airport (DEN) | nonstop | found 4 days ago | Open this trip |
| 28 Dec | $206 | Frontier Airlines | Ontario International Airport (ONT) → Denver International Airport (DEN) | nonstop | found 4 days ago | Open this trip |
| 3 Jan 2027 | $197 | Frontier Airlines | Ontario International Airport (ONT) → Denver International Airport (DEN) | nonstop | found yesterday | Open this trip |
| 15 Jan 2027 | $116 | Frontier Airlines | Ontario International Airport (ONT) → Denver International Airport (DEN) | nonstop | found 3 days ago | Open this trip |
Prices are what travelers' searches on Aviasales found in the last 7 days, in US dollars: the price the seller showed on Aviasales; bags may cost extra. Fares change, so check today's price before you book. How our prices work