HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
San Diego

$172+ 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 8/20. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — SAN
May 17 — May 241
Sat 5/17
Sat 5/24
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 May 12, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

Expedia
3 stars

Round-trip from

$337
(Alaska Airlines)

One-way from

$172
(Alaska Airlines)

Popular in

February

Cheapest in

January

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
High demand for flights, 0% potential price rise
Search Deals
Cheapest flight prices on average. 1% potential price decrease ($5 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in May 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 May 12, 2025.

This Alaska Airlines deal was found by Cheapflights users on 5/12. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/106:00 amONT - SAN
1 stop8h 48mAlaska Airlines
Wed 9/106:10 pmSAN - ONT
1 stop5h 43mAlaska Airlines
Deal found 5/12$337
This United Airlines deal was found by Cheapflights users on 5/11. 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.
Wed 6/41:36 pmONT - SAN
1 stop9h 09mUnited Airlines
Thu 6/59:42 amSAN - ONT
1 stop13h 03mUnited Airlines
Deal found 5/11$397
This American Airlines deal was found by Cheapflights users on 5/10. 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.
Mon 5/264:35 pmONT - SAN
1 stop16h 00mAmerican Airlines
Fri 5/307:22 pmSAN - ONT
1 stop13h 39mAmerican Airlines
Deal found 5/10$444

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 May 12, 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

Wed 9/10

6:00 am-2:48 pm

1 stop8h 48m

San Diego

Wed 9/10

6:10 pm-11:53 pm

1 stop5h 43m

$337

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Wed 6/4

1:36 pm-10:45 pm

1 stop9h 09m

San Diego

Thu 6/5

9:42 am-10:45 pm

1 stop13h 03m

$397

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Mon 5/26

4:35 pm-8:35 am

1 stop16h 00m

San Diego

Fri 5/30

7:22 pm-9:01 am

1 stop13h 39m

$444

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Wed 8/20

3:04 pm-9:53 pm

1 stop6h 49m

$172

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Tue 8/19

1:42 pm-10:15 am

1 stop20h 33m

$201

OntarioSan Diego

ONT - SAN

ONTSAN

Ontario

Sun 6/1

6:00 am-3:15 pm

2 stops9h 15m

$393

Flights are sorted by cheapest round-trip flights first.

Deals found on 5/12

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 May.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*2 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 Expedia the most. Expedia 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, 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 May 12, 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.

Rainfall in San Diego by month

Plan your trip to San Diego by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in San Diego ranges from 0.0 - 2.3 inches per month. February is typically the wettest month, when rainfall can reach 2.3 in. July is typically the driest time to visit San Diego when rainfall is around 0.0 in.

Temperature in San Diego by month

Plan your trip to San Diego by taking into account the average temperature totals by month.

If weather is an important factor for your trip to San Diego, use this chart to help with planning. For those seeking warmer temperatures, August is the ideal time of year to visit, when temperatures reach an average of 71.6 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 57.2 F).

Reviews of airlines servicing San Diego

Get insights into the airlines that provide service to San Diego. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to San Diego. Reviews last updated May 12, 2025.
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Comfort

7.9

Crew

8.5

Food

7.1

Overall

8.0

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Comfort

7.9

Crew

8.5

Food

7.1

Overall

8.0

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
United Airlines
7.4
Good
8,724 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Comfort

7.9

Crew

8.5

Food

7.1

Overall

8.0

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Comfort

7.9

Crew

8.5

Food

7.1

Overall

8.0

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

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.

  • What are the cheapest airlines flying from Ontario to San Diego round-trip?

    Cheapflights users have booked flights from Ontario to San Diego round-trip from $337. Other airlines that can offer you cheap pricing are United Airlines, from $397, and American Airlines, from $444.

  • 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 Ontario?

Book flights to Ontario if you plan to visit one of these locations
El Cajon
Chula Vista
Lemon Grove
National City
Imperial Beach
La Mesa
Alpine
Poway
Santee
Coronado

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.
Los Angeles to Las Vegas flights
Burbank to Las Vegas flights
San Jose to Los Angeles flights
Santa Ana to Las Vegas flights
San Francisco to Las Vegas flights
Los Angeles to San Francisco flights
San Francisco to Los Angeles flights
Los Angeles to San Jose flights
San Jose to Las Vegas flights
Los Angeles to Oakland flights
Oakland to Santa Ana flights
Oakland to Los Angeles flights
Oakland to Las Vegas flights
San Francisco to Ontario flights
Santa Ana to Oakland flights
Ontario to San Francisco flights
Oakland to Burbank flights
San Francisco to San Diego flights
Burbank to Oakland flights
Ontario to Las Vegas flights
San Francisco to Santa Ana flights
Oakland to San Diego flights
San Jose to Santa Ana flights
Santa Ana to San Francisco flights
Los Angeles to Sacramento flights
San Francisco to Burbank flights
Sacramento to Los Angeles flights
Sacramento to Las Vegas flights
Santa Ana to San Jose flights
San Diego to Las Vegas flights
Burbank to San Francisco flights
San Jose to San Diego flights
San Diego to San Francisco flights
Las Vegas to Los Angeles flights
Sacramento to San Diego flights
Los Angeles to Reno flights
San Diego to Sacramento flights
Ontario to San Jose flights
San Diego to San Jose flights
San Francisco to Palm Springs flights
San Jose to Burbank flights
Las Vegas to Santa Ana flights
Burbank to San Jose flights
Santa Ana to Sacramento flights
Burbank to Sacramento flights
San Jose to Ontario flights
Sacramento to Santa Ana flights
Sacramento to Burbank flights
Las Vegas to Burbank flights
Fresno to San Diego 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.