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$39 Find Cheap Flights from California to Ontario - Compare and Save

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Cheap Flights from California to Ontario

 
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from California to Ontario

Mon, Nov 2 - Thu, Nov 5
Frontier Logo
6:02 pm - 7:28 pmSFO  San Francisco-ONT Ontario
1h 26mnonstop
Frontier Logo
12:01 pm - 1:36 pmONT  Ontario-SFO San Francisco
1h 35mnonstop
$58Frontier
Mon, Oct 26 - Thu, Nov 5
Frontier Logo
6:02 pm - 7:40 pmSFO  San Francisco-ONT Ontario
1h 38mnonstop
Frontier Logo
12:01 pm - 1:36 pmONT  Ontario-SFO San Francisco
1h 35mnonstop
$58Frontier
Mon, Sep 14 - Thu, Sep 17
Southwest Logo
6:30 am - 7:50 amSJC  San Jose-ONT Ontario
1h 20mnonstop
Southwest Logo
3:40 pm - 4:55 pmONT  Ontario-SJC San Jose
1h 15mnonstop
$117Southwest
Mon, Sep 21 - Mon, Sep 28
Southwest Logo
6:30 am - 7:50 amSJC  San Jose-ONT Ontario
1h 20mnonstop
Southwest Logo
3:40 pm - 4:55 pmONT  Ontario-SJC San Jose
1h 15mnonstop
$117Southwest
Tue, Sep 15 - Sat, Sep 19
United Airlines Logo
12:30 pm - 2:01 pmSFO  San Francisco-ONT Ontario
1h 31mnonstop
United Airlines Logo
1:56 pm - 3:25 pmONT  Ontario-SFO San Francisco
1h 29mnonstop
$117United Airlines
Wed, Oct 28 - Mon, Nov 2
United Airlines Logo
6:50 pm - 8:15 pmSFO  San Francisco-ONT Ontario
1h 25mnonstop
United Airlines Logo
9:25 am - 10:55 amONT  Ontario-SFO San Francisco
1h 30mnonstop
$117United Airlines
Tue, Sep 15 - Wed, Sep 23
Alaska Airlines Logo
2:09 pm - 3:47 pmSTS  Santa Rosa Sonoma County-ONT Ontario
1h 38mnonstop
Alaska Airlines Logo
4:27 pm - 6:07 pmONT  Ontario-STS Santa Rosa Sonoma County
1h 40mnonstop
$150Alaska Airlines
Thu, Sep 17 - Tue, Sep 22
Alaska Airlines Logo
2:09 pm - 3:47 pmSTS  Santa Rosa Sonoma County-ONT Ontario
1h 38mnonstop
Alaska Airlines Logo
4:27 pm - 6:07 pmONT  Ontario-STS Santa Rosa Sonoma County
1h 40mnonstop
$151Alaska Airlines
Sat, Oct 17 - Tue, Oct 20
Delta Logo
5:05 pm - 10:11 pmSMF  Sacramento Intl-ONT Ontario
5h 06m1 stop Salt Lake City
Delta Logo
5:03 pm - 10:30 pmONT  Ontario-SMF Sacramento Intl
5h 27m1 stop Salt Lake City
$197Delta
Sat, Oct 17 - Wed, Oct 21
Delta Logo
5:05 pm - 10:11 pmSMF  Sacramento Intl-ONT Ontario
5h 06m1 stop Salt Lake City
Delta Logo
5:03 pm - 10:30 pmONT  Ontario-SMF Sacramento Intl
5h 27m1 stop Salt Lake City
$197Delta
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Good to know

Low season

January

Cheapest flight

$39
Best time to beat the crowds with an average 10% drop in price.
Most popular time to fly and prices are also 20% lower on average.
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.
8.0
SouthwestOverall score based on 4205 reviews
7.5Entertainment
8.6Crew
7.0Food
8.0Comfort
8.1Boarding
Airline reviews

Seated at front bulkhead for a smidge extra leg room away from home and on flight back home. Away crew was very proactive about assuring our carryons had space close behind us (because no seat in front of us our personal items had to be in a small bin overhead). They actively required passengers place overhead luggage on its side so more items could fit in bins. Home crew made no such efforts. I had to struggle back rows to get overhead bags upon landing, no crew help then either, and some disgruntled passengers as I and others retrieved our bags. There was a system that worked pretty well. The home bound crew just didn't feel like working.

4.0 OkayMather, Aug 2026
Read more Southwest reviews

Seated at front bulkhead for a smidge extra leg room away from home and on flight back home. Away crew was very proactive about assuring our carryons had space close behind us (because no seat in front of us our personal items had to be in a small bin overhead). They actively required passengers place overhead luggage on its side so more items could fit in bins. Home crew made no such efforts. I had to struggle back rows to get overhead bags upon landing, no crew help then either, and some disgruntled passengers as I and others retrieved our bags. There was a system that worked pretty well. The home bound crew just didn't feel like working.

Flight left on time and was early landing. Seats not comfortable and not enough space…

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.

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.

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.

The flight was excellent. Their was no service as we boarded, the flight attendants spent about 30 minutes just taking and not really caring that the cabin was about 80 degrees and did not offered any beverage to first class passengers or any passenger. The flight from DEN to ONT is not long but not under an hour, we received one drink and bag of chips if you were lucky. I was in first class…. I did leave my hat on the plane and it only took less than five minutes for a United rep to locate and bring it to me.

It was a short, comfortable flight. It did leave an hour late due to the pilot having to be replaced (family emergency) but that didn’t inconvenience myself & my friend. The situation was explained, eventually.

UA594 was delayed multiple times. I ended up getting picked up so I can make it in time for work 6AM on Monday, 7/6/2026

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

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.

JFK is the worst airport and JetBlue is the worst airline

A more comfortable seat. Padding would be really helpful but I've read the airlines don't want customers to be satisfied with economy seats.

Everything was good except checking bags . I had paid for two bags but it didn’t show so we had to do it again while people waited and we were struggling to get to our flight

Flight delayed 4 times on a non-stop from BOS to SFO. Then when landed in SFO had to wait for 30 mins for a gate AT 3:30AM.

The security line at JFK was one of the longest I’ve ever experienced - probably 45 minutes. I don’t know if JetBlue has control over it, but it detracted from the overall experience. Entertainment had good options, but the volume control was a bit small to tap on and the screen had a fair amount of interference blips. Clearer picture would have been better.

Whole experience was poor. Delayed 2 hours. Lied about the delays. Was all jet blues fault and tried to blame on air traffic control. Sent out other let trips and wouldn't allow people to switch aircraft.

It was fine for what it was. It’s not luxury travel but it was efficient, for the most part. Having my carry-on transferred into luggage however, was unwelcome.

I was seated next to an autistic child who was out of control and had a child behind me kicking my seat for most of the trip. I will never fly JetBlue again. Ever. I don't care how cheap it is. It's terrible.

Great price, easy check in, love the free drinks and snacks, and nice crew. The only negative part was waiting for your seat assignment 5 minutes before boarding, and the seats are a bit uncomfortable.

the staff was very helpful and the airline was very good.

I really didn't like anything. Paid for my checked luggage online ($79) and then was told that I would have to paid another $79 for my carry on. Was not allowed to enter the terminal until 3 hours before my flight and when I finally was allowed to check my bag and enter, my flight was delayed 3 times. When I finally landed, we were all instructed to "run off the plane" as they had to do a quick turn around to Las Vegas. Me and several of my flying companions will never fly Frontier again.

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.

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