ONT

$43 Find Cheap Flights from California to Ontario - Compare and Save

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight to Ontario departing on 9/2. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

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Flight Deals

Cheap Flights from California to Ontario

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from California to Ontario that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from California to Ontario

Tue, Jul 28 - Wed, Jul 29
Frontier Logo
11:15 am - 12:53 pm
SFO
-
ONT
1h 38mnonstop
Frontier Logo
8:58 am - 10:30 am
ONT
-
SFO
1h 32mnonstop
$71Frontier
Sat, Aug 1 - Tue, Aug 4
Frontier Logo
9:33 am - 11:07 am
SFO
-
ONT
1h 34mnonstop
Frontier Logo
8:58 am - 10:30 am
ONT
-
SFO
1h 32mnonstop
$75Frontier
Thu, Jul 23 - Mon, Jul 27
Alaska Airlines Logo
4:35 pm - 6:03 pm
STS
-
ONT
1h 28mnonstop
Alaska Airlines Logo
6:43 pm - 8:14 pm
ONT
-
STS
1h 31mnonstop
$125Alaska Airlines
Thu, Jul 23 - Mon, Jul 27
Alaska Airlines Logo
4:35 pm - 6:03 pm
STS
-
ONT
1h 28mnonstop
Alaska Airlines Logo
6:43 pm - 8:14 pm
ONT
-
STS
1h 31mnonstop
$128Alaska Airlines
Wed, Aug 12 - Wed, Aug 19
Southwest Logo
8:55 am - 10:15 am
SMF
-
ONT
1h 20mnonstop
Southwest Logo
9:10 am - 10:30 am
ONT
-
SMF
1h 20mnonstop
$172Southwest
Wed, Aug 12 - Wed, Aug 19
Southwest Logo
6:05 am - 10:25 am
SMF
-
ONT
4h 20m
1 stop
Southwest Logo
9:10 am - 10:30 am
ONT
-
SMF
1h 20mnonstop
$175Southwest
Thu, Aug 6 - Thu, Aug 13
United Airlines Logo
6:00 am - 12:12 pm
SMF
-
ONT
6h 12m
1 stop
United Airlines Logo
6:08 am - 9:33 am
ONT
-
SMF
3h 25m
1 stop
$179United Airlines
Fri, Aug 28 - Mon, Aug 31
United Airlines Logo
2:27 pm - 8:01 pm
SMF
-
ONT
5h 34m
1 stop
United Airlines Logo
1:56 pm - 6:20 pm
ONT
-
SMF
4h 24m
1 stop
$184United Airlines
Tue, Aug 11 - Sat, Aug 15
Delta Logo
5:00 pm - 11:34 pm
SMF
-
ONT
6h 34m
1 stop
Delta Logo
6:00 am - 12:18 pm
ONT
-
SMF
6h 18m
1 stop
$197Delta
Tue, Aug 4 - Tue, Aug 4
Delta Logo
6:00 am - 12:16 pm
RNO
-
ONT
6h 16m
1 stop
Delta Logo
5:05 pm - 11:52 pm
ONT
-
RNO
6h 47m
1 stop
$235Delta
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Good to know

Low seasonJanuary
Cheapest flight$43
Best time to beat the crowds with an average 5% drop in price.
Most popular time to fly with an average 4% increase in price.
Flight from San Francisco to Ontario

FAQs for booking flights from California to Ontario

  • How does KAYAK find such low prices on flights from California to Ontario?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from California to Ontario.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from California to Ontario?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Ontario from California is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from California to Ontario?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Ontario with an airline and back to California with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from California to Ontario?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Ontario from California up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Reviews of the top 5 airlines serving from California to Ontario

 
Need help choosing which airline to fly with from California to Ontario? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
7.9
Alaska AirlinesOverall score based on 12636 reviews
8.5Crew
7.0Entertainment
7.1Food
8.1Boarding
7.8Comfort
Airline reviews

The food selections were not good, and entertainment was non existent.

8.0 ExcellentAnonymous, Dec 2025
PDX - ONT
Read more Alaska Airlines reviews

The food selections were not good, and entertainment was non existent.

Staff inside Portland terminal were rude, made us fell rushed and not at all accommodating to seniors. For this alone I will probably never booked from them again.

Loved the staff ease of flying snacks and free movies and WiFi

Flight was very warm. It felt like there was no working AC.

Delayed. It's not our first flight with them either, it's actually our 3rd and all 3 were delayed by hours each time. It was a myriad of delays. On one flight we boarded after being delayed for a little over an hr, only to be told we were going to sit in the plane for another hour before departing. Once landed, we waited another 40ish min to get to our gate. On another flight, flight was delayed just under 3 hrs but atleast we got to wait it out at the airport terminal. Its just a bad experience overall flying with Alaska Airlines.

Flight last minute delayed 2 hours for crew calling out sick

Alaska Airlines needs more bag tag kiosks and bag check-in stations in Seattle. A single entry point for the bag tag kiosks would be helpful. This alleviates lines forming at each individual kiosk, which causes traffic jams for people passing through.

Probably one of the best flights I’ve had! From entering the airport, to boarding to landing.

Finally get a snack n drinks! Just like the good ole days!

My main complaint is specifically with having booked through kayak. Our flight was delayed and I was no longer able to access my boarding pass through the kayak app. Fortunately I had screen capped it. If I had not it would have been critical problem while boarding.

It was just okay, no frills, basic transportation with no luxury. No screens on the seats, no water or drinks on a short flight. Full flight but at least it was on time.

Boarding was easy. The seats are small and fairly uncomfortable

The problem with the seat assignments is that there were a lot of rows in the front that were empty but my row at the back was full. Just not so pleasant.

Good but I prefer choose your own seat. With the new assigned seats they should board from the back I see no advantage to this new boarding. Just like every other airline

The charges were ridiculous for an hour flight and the turbulence was very scary.

3 hour delay. Had to change plans and was still delayed.

The boarding and seat assignment system no longer works for me, but I know it is being replaced. Otherwise, I am good with the overall experience.

The lead steward kept singing about "San Francisco" and hotel California---more annoying than humorous....needs work. Flight was smooth and on time.

Our flight to Oakland was great bc the plane was new but it was delayed by 15min not bad at all. Over all it was an 8/10

The flight in it self was good. The delays looking for pilots was unexpected.

Flight delayed four separate times. I’m now one hour hours late to landing.

While they turned off most cabin lights to allow people to sleep, I was bothered by how bright the side lights still were. It was still quite bright for me in a window seat, when I wish I could have slept!

Generally on time departures and arrivals, clean planes, sky miles membership provides great benefits (complimentary upgrades, etc).

Awesome! On time flight, early arrival, and a complimentary upgrade!

Staff were friendly and happy. Delta could make sure passengers that don't have the app know of changes. Without Kayak I would not have known about the change of gate or the delay. Kayak was faster to notify me.

There are 4 flights in consecutive gates with about the same departure time. Two flights were boarding at the same time. One was delayed or boarding would be happening at the same time. I am not sure what Delta and LAX need to do to have a better layout at the end of Terminal 2

There was a loud squeaky sound the whole time we were flying.

Like most domestic flights in the US, you are basically on your own with this airline when it comes to food, so be sure to purchase meals and drinks ahead of time or expect to arrive starving and dehydrated (like I was).

You need to be a hacker to get the (Free) WiFi

I guess they don’t serve drinks on planes anymore

Service was professional and quick. Premium economy seat was comfortable given the class

The staff was extremely helpful and friendly at all times! They went above and beyond to get us into an earlier flight in San Diego to make our connection in SFO possible, because our original flight did actually not make it! I did so much appreciate the UA team and how they made this possible. We also didn’t have seats together on the long flight to Singapore, but they found us seats together last moment with no additional cost! Nobody sat next to us, so that we were able to sleep! Thanks to UA for improving their service and Underpricer for booking this trip! Please be careful: 1,5 hrs for transfer in San Francisco might not be enough time in the future

Seat pitch is horrible especially on the 15 hour flight. Gate crew at SFO was Outstanding. The flight crew was also great.

Late plane. Only one crew on the ground so we b had to wait for Denver flight to come in, board, and depart. At 78 yrs of age I was not pleased trying to get my connection. What really made me angry was the notification you sent me to hurry up or I would miss my connection. Why tell me to hurry up when you got me in late. It was not a good way of treating customers.

Outstanding service, efficient & friendly crew, flight was safe, comfortable & on time

Flight delayed for more than 16 hrs and no effort was spent to provide an alternate

it was a very short flight so my expectations were low.

Very disappointing given gate agent behavior. Filed a formal complaint with United.

Flight delayed. WiFi connectivity very poor if not existant. Last minute arrival forced me to run to catch my connection.

Airline did not explain reasons why flight was delayed two hours. Explanations were badly needed and rarely provided. Problem seemed to clearly be the airline’s fault and not the fault of the weather or airport.

The crew was mostly okay. The flight attendant who answered our questions was curt and unhelpful unfortunately. He seemed upset and I understand having off days.

No frills for sure. No gate announcements about flight delay, not even water to drink on the flight.

Charges unexpected. For seat that didnt recline. Please reverse extra seat and carryon charge. Bad business that is a bait and switch.

I couldn’t check in because the app didn’t work. It took 3 Frontier employees at the counter to get me checked in. Flight left 3 hours after departure time

Stop changing gates at sfo. When you are elderly going back for it’s not fun.

There was no easy way to check in. I don't want to install an app to checkin. I will use alaska from now on because they have a web check in method that is easy.

Flight was cancelled and was not able to get another flight thru Frontier. Per frontier a refund was issued but I do not see a refund on my Afirm account.

The agent at check-in was strident, unwelcoming, and condescending to customers ahead of me.

Was charged 99 dollars for a bag despite agents previously telling me it would be ok. Customer service was unhelpful

I will like you ( Frontier Airlines) to fly into LAX instead of ONT because I live in LA and the subway takes me to my house in just 15 minutes

Everything you need to know for your flight to Ontario

Information on the airport you'll fly into in Ontario