Denver (DEN) to Ontario (ONT) flights
3 airlines fly nonstop from Denver (DEN) to Ontario (ONT): Frontier Airlines, Southwest Airlines and United Airlines. The two airports are 817 miles (1,315 km) apart. United Airlines is in Star Alliance. There are also 9 ways to fly it with one stop, through Las Vegas, Phoenix and Salt Lake City and more.
Airlines flying nonstop from DEN to ONT
- Frontier AirlinesNot in an allianceWho books it
- Southwest AirlinesNot in an allianceWho books it
- United AirlinesStar Alliance · bookable with 13 programsWho books it
Book DEN to ONT with points
Loyalty programs that can book at least one of the nonstop airlines, from the Award Booking Guide.
- Air Canada AeroplanBooks United Airlines
- Air New Zealand AirpointsBooks United Airlines
- ANA Mileage ClubBooks United Airlines
- Avianca LifeMilesBooks United Airlines
- Emirates SkywardsBooks United Airlines
- EVA Air Infinity MileageLandsBooks United Airlines
- JetBlue TrueBlueBooks United Airlines
- Lufthansa Miles & MoreBooks United Airlines
- Singapore Airlines KrisFlyerBooks United Airlines
- TAP Miles&GoBooks United Airlines
- Thai Royal Orchid PlusBooks United Airlines
- Turkish Airlines Miles&SmilesBooks United Airlines
- United MileagePlusBooks United Airlines
DEN to ONT with one stop
9 connections, most direct first. 2-stop routings and flight times are in Routes with Pro.
- Via Las Vegas (LAS)Frontier Airlines and Southwest Airlines the whole way
- Via Phoenix (PHX)American Airlines and Southwest Airlines the whole way
+1 - Via Salt Lake City (SLC)Delta Air Lines the whole way
+1 - Via San Jose (SJC)Southwest Airlines the whole way
- Via Sacramento (SMF)Southwest Airlines and Frontier Airlines the whole way
- Via Boise (BOI)Frontier Airlines, United Airlines and 1 more, then Alaska Airlines
- Via Oakland (OAK)Southwest Airlines the whole way
- Via San Francisco (SFO)Frontier Airlines and United Airlines the whole way
- Via Santa Rosa (STS)Southwest Airlines, then Alaska Airlines
DEN to ONT: common questions
Which airlines fly nonstop from DEN to ONT?
Frontier Airlines, Southwest Airlines and United Airlines (Star Alliance) fly nonstop from Denver (DEN) to Ontario (ONT).
How far is Denver from Ontario by plane?
Denver (DEN) and Ontario (ONT) are 817 miles (1,315 km) apart along the great circle, the shortest path a flight can take. Connections add distance on top.
Which points programs can book DEN to ONT award flights?
13 programs can book at least one of the nonstop airlines: Air Canada Aeroplan, Air New Zealand Airpoints, ANA Mileage Club, Avianca LifeMiles, Emirates Skywards, EVA Air Infinity MileageLands, JetBlue TrueBlue, Lufthansa Miles & More and 5 more. Which flights each can book depends on its partners, so check the airline before you transfer points.
How many miles does DEN to ONT cost?
It depends on the program: each prices the route from its own chart or dynamically. The Award Flight Pricer compares 30+ programs for DEN to ONT with taxes and fees.
Where can I connect between Denver and Ontario?
The most direct connections are through Las Vegas (LAS), Phoenix (PHX), Salt Lake City (SLC), San Jose (SJC) and Sacramento (SMF). On 7 of them the same airline flies both flights, for example Frontier Airlines through Las Vegas.
More routes
Routes are scheduled nonstop flights. The route data is refreshed monthly; this list was last checked November 11, 2026. Seasonal routes and new launches can be missing or end early, so confirm with the airline before you book. Distances are great-circle, the shortest path between the two airports.