Direct (nonstop) flights from Denver to Ontario
3 airlines fly nonstop from Denver International (DEN) to Ontario International Airport (ONT). It's 818 miles (1,316 km), about 2h 20m in the air. Operated by Frontier Airlines, United Airlines, Southwest Airlines.
Frontier Airlines
United Airlines
Southwest Airlines
Route data last updated: May 31, 2026
Airlines with non-stop flights
F9
Frontier Airlines
UA
United Airlines
WN
Southwest Airlines
Alternative Routes
Other ways to fly from Denver to Ontario with one stop · direct emits 151 kg CO₂ per passenger
Looking for the return flight?
ONT → DEN: Flights from Ontario to DenverOther direct flights from Denver
Direct flights from Ontario (ONT)
Frequently Asked Questions
How long is the direct flight from Denver to Ontario?
A nonstop flight from Denver (DEN) to Ontario (ONT) takes approximately 2 hours and 20 minutes. The distance is 818 miles (1,316 km).
Which airlines fly nonstop from Denver to Ontario?
3 airlines: Frontier Airlines, United Airlines, Southwest Airlines.
Is there a nonstop flight from Denver to Ontario?
Yes. 3 airlines: Frontier Airlines, United Airlines, Southwest Airlines.
How far is Denver from Ontario?
The flight distance from Denver to Ontario is 818 miles (1,316 km), measured as the great-circle (shortest air) distance. That's roughly the same distance as London to Madrid.
What type of aircraft flies from Denver to Ontario?
At 2h 20m, this route typically uses narrow-body or mid-range jets — Boeing 737 MAX or Airbus A320neo. Varies by airline.
What is the carbon footprint of a flight from Denver to Ontario?
Roughly 151 kg CO2 per passenger one-way. That's about the same as driving 755 km.
Is the return flight from Ontario to Denver also nonstop?
Yes — nonstop flights run both ways. Flight time may differ slightly due to wind patterns.
When is the cheapest time to fly from Denver to Ontario?
Midweek flights (Tue/Wed) outside holiday peaks are usually cheapest. 3-6 weeks ahead is a good window for this route. Use "Check Prices" above to compare.
How early should I arrive at Denver International for this flight?
1.5-2 hours for domestic. Add more time during holidays or busy travel weekends.