HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
San Diego

$79+ 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 9/28. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — SAN
Oct 17 — Oct 241
Fri 10/17
Fri 10/24
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Ontario to San Diego with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheap 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 September 17, 2025.

Round-trip from

$149
(Kiwi.com)

One-way from

$79
(Kiwi.com)

Popular in

September

Cheapest in

January

Average price

$259
From Ontario to San Diego
Search Deals
One-way flight from Ontario to San Diego
Search Deals
Highest demand for flights based on searches. 10% potential increase in price ($26 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease ($4 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in September 2025
Search Deals

Find 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 September 17, 2025.

This Kiwi.com deal was found by Cheapflights users on 9/14. 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.
Tue 9/308:00 amONT - SAN
1 stop4h 31mMultiple Airlines
Sat 10/46:15 amSAN - ONT
1 stop6h 28mMultiple Airlines
Deal found 9/14$144
This Kiwi.com deal was found by Cheapflights users on 9/15. 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 11/186:53 amONT - SAN
1 stop6h 35mFrontier
Thu 11/206:36 amSAN - ONT
1 stop17h 21mFrontier
Deal found 9/15$154
This Kiwi.com deal was found by Cheapflights users on 9/15. 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 10/1310:47 pmONT - SAN
1 stop22h 33mFrontier
Mon 10/205:28 pmSAN - ONT
1 stop6h 44mFrontier
Deal found 9/15$161
This Kiwi.com deal was found by Cheapflights users on 9/16. 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.
Wed 10/18:00 amONT - SAN
1 stop23h 29mMultiple Airlines
Sun 10/512:33 pmSAN - ONT
1 stop18h 44mMultiple Airlines
Deal found 9/16$169
This Kiwi.com deal was found by Cheapflights users on 9/15. 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.
Wed 10/158:00 amONT - SAN
1 stop13h 20mFrontier
Wed 10/228:00 amSAN - ONT
1 stop12h 42mFrontier
Deal found 9/15$171
This Kiwi.com deal was found by Cheapflights users on 9/15. 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 10/96:05 amONT - SAN
1 stop5h 56mFrontier
Mon 10/139:03 pmSAN - ONT
1 stop26h 47mFrontier
Deal found 9/15$172
This Frontier deal was found by Cheapflights users on 9/15. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/248:34 amONT - SAN
1 stop10h 14mFrontier
Sun 10/267:23 pmSAN - ONT
1 stop12h 26mFrontier
Deal found 9/15$176
This Frontier deal was found by Cheapflights users on 9/16. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/238:34 amONT - SAN
1 stop9h 54mFrontier
Sat 10/252:24 pmSAN - ONT
1 stop9h 26mFrontier
Deal found 9/16$180
This Kiwi.com deal was found by Cheapflights users on 9/16. 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 11/112:05 pmONT - SAN
1 stop10h 20mFrontier
Sat 11/86:41 amSAN - ONT
1 stop17h 09mFrontier
Deal found 9/16$182
This Kiwi.com deal was found by Cheapflights users on 9/16. 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 10/111:37 pmONT - SAN
1 stop7h 14mFrontier
Mon 10/139:03 pmSAN - ONT
1 stop26h 47mFrontier
Deal found 9/16$190
This Kiwi.com deal was found by Cheapflights users on 9/14. 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.
Tue 9/308:00 amONT - SAN
1 stop13h 24mFrontier
Sat 10/47:20 pmSAN - ONT
2 stops36h 33mFrontier
Deal found 9/14$197

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 September 17, 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

Mon 10/13

10:47 pm-9:20 pm

1 stop22h 33m

San Diego

Mon 10/20

5:28 pm-12:12 am

1 stop6h 44m

$161

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Wed 10/1

8:00 am-7:29 am

1 stop23h 29m

San Diego

Sun 10/5

12:33 pm-7:17 am

1 stop18h 44m

$169

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Thu 10/9

6:05 am-12:01 pm

1 stop5h 56m

San Diego

Mon 10/13

9:03 pm-11:50 pm

1 stop26h 47m

$172

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Fri 10/24

8:34 am-6:48 pm

1 stop10h 14m

San Diego

Sun 10/26

7:23 pm-7:49 am

1 stop12h 26m

$176

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Sat 11/1

12:05 pm-10:25 pm

1 stop10h 20m

San Diego

Sun 11/2

7:24 pm-7:29 am

1 stop12h 05m

$180

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Sat 10/25

7:04 am-1:28 pm

1 stop6h 24m

San Diego

Sun 10/26

7:23 pm-7:49 am

1 stop12h 26m

$180

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Thu 10/23

8:34 am-6:28 pm

1 stop9h 54m

San Diego

Sat 10/25

2:24 pm-11:50 pm

1 stop9h 26m

$180

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Sat 11/1

12:05 pm-10:25 pm

1 stop10h 20m

San Diego

Sat 11/8

6:41 am-11:50 pm

1 stop17h 09m

$182

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Sat 10/11

1:37 pm-8:51 pm

1 stop7h 14m

San Diego

Mon 10/13

9:03 pm-11:50 pm

1 stop26h 47m

$190

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Thu 10/9

8:34 am-6:28 pm

1 stop9h 54m

San Diego

Sun 10/12

7:23 pm-7:49 am

1 stop12h 26m

$212

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/17

Showing 1-10 of 18 results
1
2

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, August is the cheapest month in which you can book a flight from Ontario to San Diego (average of $286). Flying from Ontario to San Diego in March is currently the most expensive (average of $366). 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 September 17, 2025.

It’s typically best to fly out from Ontario to San Diego in the morning. Doing so could potentially save you 28% on the flight price compared to flying at noon, 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 22h 33m. Frontier provides one of the quickest options available for as low as $161. 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, August is the cheapest month in which you can book a flight from Ontario to San Diego (average of $286). Flying from Ontario to San Diego in March is currently the most expensive (average of $366). 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
La Mesa
Poway
Lemon Grove
Coronado
Imperial Beach
National City

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Ontario to San Diego

See prices for flight routes from nearby airports that may be better suited for you.
San Francisco to Las Vegas flights
Los Angeles to San Francisco flights
Los Angeles to Las Vegas flights
San Francisco to Los Angeles flights
San Francisco to Ontario flights
Santa Ana to Las Vegas flights
San Francisco to Santa Ana flights
Burbank to Las Vegas flights
Oakland to Las Vegas flights
Los Angeles to San Jose flights
San Jose to Los Angeles flights
Ontario to San Francisco flights
Santa Ana to San Francisco flights
San Jose to Las Vegas flights
San Francisco to San Diego flights
Ontario to Las Vegas flights
San Francisco to Burbank flights
San Francisco to Palm Springs flights
Burbank to San Francisco flights
San Diego to Las Vegas flights
San Jose to Santa Ana flights
Sacramento to Las Vegas flights
Oakland to Los Angeles flights
Sacramento to Los Angeles flights
Los Angeles to Sacramento flights
San Diego to San Francisco flights
Oakland to Burbank flights
San Jose to San Diego flights
Oakland to Santa Ana flights
Sacramento to San Diego flights
Stockton to Las Vegas flights
Oakland to San Diego flights
Los Angeles to Reno flights
San Jose to Ontario flights
Las Vegas to Los Angeles flights
Santa Rosa to Las Vegas flights
Fresno to Las Vegas flights
Santa Ana to Oakland flights
Sacramento to Ontario flights
San Diego to San Jose flights
Ontario to Sacramento flights
San Diego to Sacramento flights
Long Beach to Las Vegas flights
Santa Ana to San Jose flights
Las Vegas to Santa Ana flights
Sacramento to Santa Ana flights
Santa Rosa to Los Angeles flights
Long Beach to San Francisco flights
Las Vegas to Burbank flights
Reno to Los Angeles flights

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.