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San Diego

$137+ Cheap flights from Ontario to San Diego (ONT - SAN)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 3/15. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — SAN
Feb 28 — Mar 71
Sat 2/28
Sat 3/7
1 adult, Economy
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Cheap flight deals from Ontario to San Diego

Cheapest flights from Ontario to San Diego
Explore the most affordable flight options available from Ontario to San Diego. Find the lowest fares from popular airlines and budget airlines, with prices last updated on January 29, 2026.

This Kiwi.com deal was found by Cheapflights users on 1/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 2/197:22 pm
ONT
-
SAN
1 stop24h 01m
Frontier
Mon 2/238:20 pm
SAN
-
ONT
2 stops25h 14m
Frontier
Deal found 1/28$140
This Kiwi.com deal was found by Cheapflights users on 1/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 2/267:22 pm
ONT
-
SAN
1 stop24h 01m
Frontier
Thu 3/56:25 am
SAN
-
ONT
1 stop17h 34m
Frontier
Deal found 1/29$141
This Kiwi.com deal was found by Cheapflights users on 1/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 2/127:22 pm
ONT
-
SAN
1 stop24h 01m
Frontier
Mon 2/162:00 pm
SAN
-
ONT
1 stop23h 11m
Frontier
Deal found 1/27$165
This Kiwi.com deal was found by Cheapflights users on 1/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 2/98:05 pm
ONT
-
SAN
2 stops24h 19m
Frontier
Thu 2/122:38 pm
SAN
-
ONT
1 stop16h 44m
Frontier
Deal found 1/26$219
This Kiwi.com deal was found by Cheapflights users on 1/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 2/216:00 am
ONT
-
SAN
1 stop18h 08m
Frontier
Sun 2/222:52 pm
SAN
-
ONT
1 stop6h 41m
Frontier
Deal found 1/28$224
This Kiwi.com deal was found by Cheapflights users on 1/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 2/122:06 pm
ONT
-
SAN
1 stop18h 44m
Frontier
Sat 2/1411:21 am
SAN
-
ONT
1 stop27h 08m
Frontier
Deal found 1/28$264
This Kiwi.com deal was found by Cheapflights users on 1/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 2/33:07 pm
ONT
-
SAN
2 stops28h 27m
Frontier
Sun 2/86:30 am
SAN
-
ONT
1 stop17h 50m
Frontier
Deal found 1/27$281
This American Airlines deal was found by Cheapflights users on 1/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 2/266:15 am
ONT
-
SAN
1 stop15h 24m
American Airlines
Thu 3/56:24 am
SAN
-
ONT
1 stop9h 58m
American Airlines
Deal found 1/29$299

Find flight deals from Ontario to San Diego

Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to San Diego (SAN). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated January 29, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$140
(Kiwi.com)

One-way from

$137
(Kiwi.com)

Popular in

December

Cheapest in

July

Average price

$278
Provider with most accurate pricing for Ontario-San Diego flight deals.
Search Deals
Provider most trusted by Cheapflights users for Ontario-San Diego flights.
Search Deals
From Ontario to San Diego
Search Deals
One-way flight from Ontario to San Diego
Search Deals
Highest demand for flights based on searches. 17% potential increase in price ($50 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($5 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in January 2026
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Ontario to San Diego that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated January 29, 2026.
Use the filters below to find and compare flights from Ontario to San Diego that are best for you.

Fly from

Ontario

Fly to

San Diego

Route

Depart

Return

Price

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Thu 2/19

7:22 pm-7:23 pm

1 stop24h 01m

San Diego

Mon 2/23

8:20 pm-9:34 pm

2 stops25h 14m

$140

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Thu 2/26

7:22 pm-7:23 pm

1 stop24h 01m

San Diego

Thu 3/5

6:25 am-11:59 pm

1 stop17h 34m

$141

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Thu 2/12

7:22 pm-7:23 pm

1 stop24h 01m

San Diego

Mon 2/16

2:00 pm-1:11 pm

1 stop23h 11m

$165

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Sat 2/21

6:00 am-12:08 am

1 stop18h 08m

San Diego

Sun 2/22

2:52 pm-9:33 pm

1 stop6h 41m

$224

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Thu 2/26

6:15 am-9:39 pm

1 stop15h 24m

San Diego

Thu 3/5

6:24 am-4:22 pm

1 stop9h 58m

$299

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Mon 2/9

6:20 am-12:08 am

1 stop17h 48m

San Diego

Thu 2/12

2:38 pm-7:22 am

1 stop16h 44m

$320

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Tue 2/24

6:14 am-9:49 pm

1 stop15h 35m

San Diego

Fri 2/27

7:26 pm-11:08 am

1 stop15h 42m

$323

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Thu 4/2

4:22 pm-9:29 pm

1 stop5h 07m

San Diego

Tue 4/7

9:14 pm-3:42 pm

1 stop18h 28m

$323

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Wed 3/11

12:02 pm-11:03 pm

1 stop11h 01m

San Diego

Wed 3/18

4:42 pm-11:59 pm

1 stop7h 17m

$323

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Tue 3/10

6:14 am-3:46 pm

1 stop9h 32m

San Diego

Wed 3/18

4:42 pm-11:59 pm

1 stop7h 17m

$323

Flights are sorted by cheapest round-trip flights first.

Deals found on 1/26

Showing 1-10 of 18 results
1
2

Compare providers for flights from Ontario to San Diego

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Ontario to San Diego in January.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Ontario-San Diego flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ontario-San Diego flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ontario-San Diego flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Ontario-San Diego flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Ontario-San Diego flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Ontario to San Diego

Have a flexible travel schedule? Discover the best time to fly to San Diego from Ontario with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Ontario to San Diego

What is the cheapest month to book a flight from Ontario to San Diego?

Currently, January is the cheapest month in which you can book a flight from Ontario to San Diego (average of $79). Flying from Ontario to San Diego in October is currently the most expensive (average of $179). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

Related info for your journey

Find useful and relevant information for your journey from Ontario to San Diego. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • How long is the flight from Ontario to San Diego?

    A quick flight from Ontario to San Diego can take about 24h 01m. Frontier provides one of the quickest options available for as low as $140. Ontario and San Diego are separated by a distance of 94 mi.

  • Can I find deals for flights from Ontario to San Diego that include hotel bookings?

    Yes. In addition to deals on Ontario to San Diego flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Ontario to San Diego?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Ontario to San Diego.

  • Can I find deals for business class flights from Ontario to San Diego?

    Yes. Cheapflights offers flight deals from Ontario to San Diego by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Ontario to San Diego?

    Currently, January is the cheapest month in which you can book a flight from Ontario to San Diego (average of $79). Flying from Ontario to San Diego in October is currently the most expensive (average of $179). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Traveling to a place near San Diego?

Book flights to San Diego if you plan to visit one of these locations
El Cajon
Chula Vista
National City
Coronado
La Mesa
Poway
Julian
Lemon Grove

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