Find Cheap Flights from Ontario to United States

Depart
Return
1 adult
Adults
18-64
Seniors
65+
Youths
12-17
Children
2-11
Seat Infants
under 2
Lap Infants
under 2
The price shown for each flight will be the average for all passengers including any infants.
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Dates flexible? Here are the best fares found in the past 48 hours...

Book cheap flights from Ontario to United States

(Round-trip)
Depart: Fri Oct 20 2017 Return: Mon Oct 23 2017 Trip spans 4 days
Frontier
Frontier
ONT
DEN
2h 19m
nonstop
DEN
ONT
2h 24m
nonstop
Depart: Tue Oct 17 2017 Return: Tue Oct 24 2017 Trip spans 8 days
United
United
ONT
PDX
5h 03m
1 stop
PDX
ONT
4h 04m
1 stop
Depart: Wed Oct 18 2017 Return: Tue Oct 24 2017 Trip spans 7 days
Alaska Airlines
Alaska Airlines
ONT
PDX
2h 23m
nonstop
PDX
ONT
2h 23m
nonstop
Depart: Sat Oct 21 2017 Return: Sat Oct 28 2017 Trip spans 8 days
Frontier
Frontier
ONT
DEN
2h 19m
nonstop
DEN
ONT
2h 24m
nonstop
Depart: Tue Oct 24 2017 Return: Wed Nov 1 2017 Trip spans 9 days
Frontier
Frontier
ONT
DEN
2h 19m
nonstop
DEN
ONT
2h 29m
nonstop
Depart: Wed Oct 25 2017 Return: Wed Nov 1 2017 Trip spans 8 days
Frontier
Frontier
ONT
DEN
2h 19m
nonstop
DEN
ONT
2h 29m
nonstop
Depart: Tue Oct 17 2017 Return: Wed Oct 25 2017 Trip spans 9 days
Frontier
Frontier
ONT
DEN
2h 19m
nonstop
DEN
ONT
2h 24m
nonstop
Depart: Wed Oct 18 2017 Return: Wed Oct 25 2017 Trip spans 8 days
Frontier
Frontier
ONT
DEN
2h 19m
nonstop
DEN
ONT
2h 24m
nonstop
Depart: Sat Oct 21 2017 Return: Tue Oct 24 2017 Trip spans 4 days
Alaska Airlines
Alaska Airlines
ONT
PDX
2h 22m
nonstop
PDX
ONT
2h 23m
nonstop
Depart: Fri Oct 20 2017 Return: Wed Oct 25 2017 Trip spans 6 days
Frontier
Frontier
ONT
DEN
2h 19m
nonstop
DEN
ONT
2h 24m
nonstop
Depart: Sat Oct 21 2017 Return: Wed Oct 25 2017 Trip spans 5 days
Frontier
Frontier
ONT
DEN
2h 19m
nonstop
DEN
ONT
2h 24m
nonstop
Depart: Sat Oct 28 2017 Return: Wed Nov 1 2017 Trip spans 5 days
Frontier
Frontier
ONT
DEN
2h 19m
nonstop
DEN
ONT
2h 29m
nonstop
Depart: Sat Nov 11 2017 Return: Wed Nov 15 2017 Trip spans 5 days
Frontier
Frontier
ONT
DEN
2h 18m
nonstop
DEN
ONT
2h 29m
nonstop
Depart: Sat Dec 9 2017 Return: Tue Dec 12 2017 Trip spans 4 days
Frontier
Frontier
ONT
DEN
2h 18m
nonstop
DEN
ONT
2h 27m
nonstop
Depart: Sat Jan 20 2018 Return: Sat Jan 27 2018 Trip spans 8 days
Frontier
Frontier
ONT
DEN
2h 24m
nonstop
DEN
ONT
2h 27m
nonstop
Depart: Sat Oct 14 2017 Return: Sat Oct 21 2017 Trip spans 8 days
Frontier
Frontier
ONT
DEN
2h 19m
nonstop
DEN
ONT
2h 24m
nonstop
Depart: Tue Oct 17 2017 Return: Sat Oct 21 2017 Trip spans 5 days
Frontier
Frontier
ONT
DEN
2h 19m
nonstop
DEN
ONT
2h 24m
nonstop
Depart: Wed Oct 18 2017 Return: Sat Oct 21 2017 Trip spans 4 days
Frontier
Frontier
ONT
DEN
2h 19m
nonstop
DEN
ONT
2h 24m
nonstop
Depart: Wed Oct 18 2017 Return: Sat Oct 21 2017 Trip spans 4 days
Frontier
Frontier
ONT
DEN
2h 19m
nonstop
DEN
ONT
2h 24m
nonstop
Depart: Fri Oct 20 2017 Return: Sat Oct 21 2017 Trip spans 2 days
Frontier
Frontier
ONT
DEN
2h 19m
nonstop
DEN
ONT
2h 24m
nonstop
* 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.

Here's why:

We’re not the seller.
At KAYAK we don’t set the prices, so it’s not possible for us to guarantee what other companies are selling.

We compile tonnes of data for you
Our service lets you quickly and easily compare results from hundreds of travel sites at once. In this sense, KAYAK is a search engine and we can't guarantee prices we find.

Why aren’t prices accurate 100% of the time?
Prices on airline seats, hotel rooms and car rentals can change frequently. Several people may also be trying to buy the same travel option simultaneously. As a result, you may find, on occasion, that certain prices are no longer available.

If you have more questions or if you have a bad price to report to us,
please send us an email and someone from our team will get back to you promptly.

Airports
Origin

Ontario
$83
Destination

Portland
$134
Denver
$83