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San Diego

$126+ 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 4/7. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — SAN
Apr 28 — May 51
Tue 4/28
Tue 5/5
1 adult, Economy
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1. Tell us where you want to go

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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 March 29, 2026.

This Kiwi.com deal was found by Cheapflights users on 3/26. 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.
Fri 4/2412:59 am
ONT
-
SAN
1 stop22h 07m
Frontier
Sat 5/27:15 am
SAN
-
ONT
1 stop16h 40m
Frontier
Deal found 3/26$152
This Kiwi.com deal was found by Cheapflights users on 3/27. 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.
Fri 4/2412:59 am
ONT
-
SAN
1 stop19h 05m
Frontier
Mon 5/2510:07 pm
SAN
-
ONT
1 stop17h 37m
Frontier
Deal found 3/27$160
This Kiwi.com deal was found by Cheapflights users on 3/25. 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 6/16:00 am
ONT
-
SAN
1 stop17h 50m
Frontier
Thu 6/410:07 pm
SAN
-
ONT
1 stop17h 02m
Frontier
Deal found 3/25$161
This Kiwi.com deal was found by Cheapflights users on 3/25. 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 5/910:50 am
ONT
-
SAN
1 stop13h 00m
Frontier
Sat 5/166:25 am
SAN
-
ONT
1 stop17h 24m
Frontier
Deal found 3/25$184
This Kiwi.com deal was found by Cheapflights users on 3/26. 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.
Thu 4/235:33 pm
ONT
-
SAN
1 stop6h 26m
Frontier
Thu 4/3012:25 pm
SAN
-
ONT
1 stop19h 06m
Frontier
Deal found 3/26$186
This Kiwi.com deal was found by Cheapflights users on 3/27. 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.
Sat 4/2512:59 am
ONT
-
SAN
1 stop7h 35m
Frontier
Sun 5/39:00 pm
SAN
-
ONT
1 stop11h 04m
Frontier
Deal found 3/27$205
This Kiwi.com deal was found by Cheapflights users on 3/29. 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.
Mon 4/1311:10 am
ONT
-
SAN
1 stop26h 07m
Frontier
Fri 4/178:49 pm
SAN
-
ONT
1 stop13h 55m
Frontier
Deal found 3/29$208
This Kiwi.com deal was found by Cheapflights users on 3/26. 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.
Fri 4/249:59 pm
ONT
-
SAN
2 stops22h 05m
Frontier
Sun 5/39:00 pm
SAN
-
ONT
1 stop11h 04m
Frontier
Deal found 3/26$209

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 March 29, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$152
(Kiwi.com)

One-way from

$126
(Kiwi.com)

Popular in

January

Cheapest in

February

Average price

$239
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. 13% potential increase in price ($37 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease ($10 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in March 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 March 29, 2026.
Use the filters below to find and compare flights from Ontario to San Diego that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Fri 4/24

12:59 am-11:06 pm

1 stop22h 07m

San Diego

Sat 5/2

7:15 am-11:55 pm

1 stop16h 40m

$152

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Fri 4/10

9:02 pm-8:26 pm

2 stops23h 24m

San Diego

Tue 4/14

2:12 pm-6:49 pm

1 stop4h 37m

$259

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Tue 4/28

12:48 pm-9:10 am

1 stop20h 22m

San Diego

Wed 4/29

5:17 pm-12:08 pm

1 stop18h 51m

$302

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Tue 4/21

4:22 pm-9:29 pm

1 stop5h 07m

San Diego

Wed 4/22

5:17 pm-12:08 pm

1 stop18h 51m

$328

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Wed 5/6

7:00 am-1:08 pm

1 stop6h 08m

San Diego

Sat 5/16

9:27 am-7:08 pm

1 stop9h 41m

$383

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Sat 5/2

12:48 pm-9:10 am

1 stop20h 22m

San Diego

Tue 5/5

5:17 pm-12:08 pm

1 stop18h 51m

$388
Quickest round-trip

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Wed 5/13

4:03 pm-10:26 pm

1 stop6h 23m

San Diego

Wed 5/20

5:17 pm-11:58 pm

1 stop6h 41m

$403

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Sat 6/6

3:35 pm-9:27 pm

1 stop5h 52m

San Diego

Wed 6/10

8:24 am-6:03 pm

1 stop9h 39m

$437

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Thu 5/7

12:48 pm-9:45 pm

1 stop8h 57m

San Diego

Mon 5/11

9:30 pm-12:08 pm

1 stop14h 38m

$481

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Mon 6/22

6:43 pm-8:15 am

1 stop13h 32m

San Diego

Sat 6/27

8:24 am-6:03 pm

1 stop9h 39m

$503

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/25

Showing 1-10 of 21 resultsSorted by cheapest first
1
2
3

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 March.
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, April 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 January 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 22h 07m. Frontier provides one of the quickest options available for as low as $152. 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, April 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 January 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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