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$99+ 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 1/23. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — SAN
Jan 13 — Jan 201
Tue 1/13
Tue 1/20
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 December 14, 2025.

This Kiwi.com deal was found by Cheapflights users on 12/14. 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 12/296:00 pmONT - SAN
1 stop18h 11mFrontier
Fri 1/27:21 pmSAN - ONT
1 stop21h 10mFrontier
Deal found 12/14$282
This Kiwi.com deal was found by Cheapflights users on 12/12. 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 12/276:00 amONT - SAN
1 stop6h 38mFrontier
Wed 12/311:06 pmSAN - ONT
1 stop8h 11mFrontier
Deal found 12/12$366
This Kiwi.com deal was found by Cheapflights users on 12/13. 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.
Sun 12/216:00 amONT - SAN
1 stop6h 11mFrontier
Wed 12/241:06 pmSAN - ONT
1 stop8h 11mFrontier
Deal found 12/13$425
This Kiwi.com deal was found by Cheapflights users on 12/14. 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 12/206:00 amONT - SAN
1 stop6h 38mFrontier
Tue 12/231:06 pmSAN - ONT
1 stop4h 16mFrontier
Deal found 12/14$494
This Kiwi.com deal was found by Cheapflights users on 12/12. 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 12/166:15 amONT - SAN
2 stops40h 31mFrontier
Fri 12/197:21 pmSAN - ONT
1 stop21h 10mFrontier
Deal found 12/12$533
This Kiwi.com deal was found by Cheapflights users on 12/14. 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.
Sun 12/145:18 pmONT - SAN
1 stop19h 20mFrontier
Mon 12/158:10 pmSAN - ONT
2 stops25h 07mFrontier
Deal found 12/14$615
This United Airlines deal was found by Cheapflights users on 12/12. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/161:50 pmONT - SAN
1 stop10h 25mUnited Airlines
Fri 12/194:00 pmSAN - ONT
1 stop17h 59mUnited Airlines
Deal found 12/12$726

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 December 14, 2025.

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$141
(Kiwi.com)

One-way from

$99
(Alaska Airlines)

Popular in

December

Cheapest in

January

Average price

$282
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. 9% potential increase in price ($22 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($6 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in December 2025
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 December 14, 2025.
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

Sun 1/11

10:18 pm-12:14 pm

1 stop13h 56m

San Diego

Sun 1/18

9:16 am-3:39 pm

1 stop6h 23m

$141

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Fri 2/6

4:03 pm-11:09 pm

1 stop7h 06m

San Diego

Mon 2/9

6:15 am-11:56 pm

1 stop17h 41m

$226

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Fri 3/6

6:14 am-11:03 pm

1 stop16h 49m

San Diego

Mon 3/9

6:15 am-11:32 pm

1 stop17h 17m

$266

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Mon 12/29

6:00 pm-12:11 pm

1 stop18h 11m

San Diego

Fri 1/2

7:21 pm-4:31 pm

1 stop21h 10m

$282

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Thu 1/8

4:03 pm-11:09 pm

1 stop7h 06m

San Diego

Mon 1/12

2:20 pm-11:56 pm

1 stop9h 36m

$295

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Mon 1/5

6:00 am-12:38 pm

1 stop6h 38m

San Diego

Mon 1/5

4:47 pm-11:59 pm

1 stop7h 12m

$314

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Sun 1/11

7:00 am-4:59 pm

1 stop9h 59m

San Diego

Wed 1/14

11:49 am-8:36 pm

1 stop8h 47m

$364

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Sun 1/4

7:57 pm-3:24 pm

1 stop19h 27m

San Diego

Wed 1/7

4:00 pm-12:03 pm

1 stop20h 03m

$389

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Thu 1/15

11:53 am-8:58 pm

1 stop9h 05m

San Diego

Mon 1/19

6:15 am-11:56 pm

1 stop17h 41m

$398

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Sun 12/21

6:00 am-12:11 pm

1 stop6h 11m

San Diego

Wed 12/24

1:06 pm-9:17 pm

1 stop8h 11m

$425

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/12

Showing 1-10 of 17 results
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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 December.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy2 starsTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*1 star
eDreamsPrice 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 eDreams to be most consistent on Cheapflights vs. eDreams Users can find the same prices on Ontario-San Diego flight deals on Cheapflights vs. eDreams >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 eDreams the most. eDreams 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 $63). 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.

What is the cheapest time of day to fly from ONT to SAN?

Find hourly flight availability from Ontario to San Diego. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated December 14, 2025.

It’s typically best to fly out from Ontario to San Diego in the evening. Doing so could potentially save you 43% on the flight price compared to flying in the afternoon, which is usually more expensive.

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 7h 06m. Frontier provides one of the quickest options available for as low as $226. Ontario and San Diego are separated by a distance of 94 mi. This flight may include one or multiple stops.

  • 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 $63). 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
Coronado
La Mesa
Poway
Lemon Grove
Julian
National City

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