$74 Cheap Flights from Ontario (ONT) to San Diego (SAN)

View $74 flight on Mon, Aug 11, 2025Opens in a new window

Popular airlines from Los Angeles - Ontario Intl. Airport (ONT) to San Diego Intl. Airport (SAN)

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Cheap Flights from Ontario to San Diego (ONT-SAN)

Prices were available within the past 7 days and start at $74 for one-way flights and $153 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Thu, Aug 28 - Tue, Sep 2
ONT
Ontario
SAN
San Diego
$153 Roundtrip, found 5 days ago
$153
Roundtrip
found 5 days ago
Select Frontier Airlines flight, departing Thu, Aug 28 from Ontario to San Diego, returning Tue, Sep 2, priced at $153 found 5 days ago
Frontier Airlines
Thu, Aug 21 - Mon, Aug 25
ONT
Ontario
SAN
San Diego
$157 Roundtrip, found 6 days ago
$157
Roundtrip
found 6 days ago
Select Frontier Airlines flight, departing Thu, Aug 21 from Ontario to San Diego, returning Mon, Aug 25, priced at $157 found 6 days ago
Frontier Airlines
Fri, Sep 12 - Mon, Sep 15
ONT
Ontario
SAN
San Diego
$162 Roundtrip, found 6 days ago
$162
Roundtrip
found 6 days ago
Select Frontier Airlines flight, departing Fri, Sep 12 from Ontario to San Diego, returning Mon, Sep 15, priced at $162 found 6 days ago
American Airlines
Mon, Aug 18 - Mon, Aug 25
ONT
Ontario
SAN
San Diego
$171 Roundtrip, found 2 hours ago
$171
Roundtrip
found 2 hours ago
Select American Airlines flight, departing Mon, Aug 18 from Ontario to San Diego, returning Mon, Aug 25, priced at $171 found 2 hours ago
Frontier Airlines
Thu, Aug 21 - Mon, Aug 25
ONT
Ontario
SAN
San Diego
$181 Roundtrip, found 6 days ago
$181
Roundtrip
found 6 days ago
Select Frontier Airlines flight, departing Thu, Aug 21 from Ontario to San Diego, returning Mon, Aug 25, priced at $181 found 6 days ago
Frontier Airlines
Fri, Jul 18 - Mon, Jul 21
ONT
Ontario
SAN
San Diego
$188 Roundtrip, found 4 days ago
$188
Roundtrip
found 4 days ago
Select Frontier Airlines flight, departing Fri, Jul 18 from Ontario to San Diego, returning Mon, Jul 21, priced at $188 found 4 days ago
Frontier Airlines
Fri, Jul 18 - Mon, Jul 21
ONT
Ontario
SAN
San Diego
$218 Roundtrip, found 4 days ago
$218
Roundtrip
found 4 days ago
Select Frontier Airlines flight, departing Fri, Jul 18 from Ontario to San Diego, returning Mon, Jul 21, priced at $218 found 4 days ago
Southwest Airlines
Mon, Sep 15 - Thu, Sep 18
ONT
Ontario
SAN
San Diego
$276 Roundtrip, found 1 day ago
$276
Roundtrip
found 1 day ago
Select Southwest Airlines flight, departing Mon, Sep 15 from Ontario to San Diego, returning Thu, Sep 18, priced at $276 found 1 day ago
Hawaiian Airlines
Tue, Aug 19 - Wed, Aug 27
ONT
Ontario
SAN
San Diego
$322 Roundtrip, found 15 hours ago
$322
Roundtrip
found 15 hours ago
Select Hawaiian Airlines flight, departing Tue, Aug 19 from Ontario to San Diego, returning Wed, Aug 27, priced at $322 found 15 hours ago
Delta
Tue, Aug 19 - Sat, Aug 30
ONT
Ontario
SAN
San Diego
$333 Roundtrip, found 15 hours ago
$333
Roundtrip
found 15 hours ago
Select Delta flight, departing Tue, Aug 19 from Ontario to San Diego, returning Sat, Aug 30, priced at $333 found 15 hours ago

Find the cheapest month to fly from Ontario (ONT) to San Diego (SAN)

September is typically the cheapest month to fly

From $181 - $498 per traveler.

Graph displaying average flight prices per month

Flights from Ontario (ONT) to San Diego (SAN)
Origin airport
Los Angeles - Ontario Intl.
Destination airport
San Diego Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Hawaiian Airlines, Southwest Airlines, United
Roundtrip price
$153
Distance
94 mi

Ontario to San Diego Flights

The cheapest times to fly from Ontario to San Diego

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Ontario to San Diego are during the month of August. You can find some of the cheapest flights from Ontario to San Diego with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Ontario to San Diego

Sunday is one of the best days to book for cheap flights from Ontario to San Diego: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from Ontario to San Diego

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Ontario to San Diego in 2025. You can also book with separate airlines for your outbound and return journeys, from $74 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Ontario to San Diego flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your Ontario to San Diego airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Frequently asked questions

How much does a flight from Los Angeles - Ontario Intl. Airport (ONT) to San Diego Intl. Airport (SAN) cost?
Discover the latest flight deals from ONT to SAN by entering your preferred travel dates and searching on Expedia. Easily compare prices by departure date if you have flexibility with your schedule and use handy filters to explore prices for your preferred journey. As a member of One Key™, our free loyalty program, you can use Price Tracking to watch fares and receive notifications if prices go up or down.
What is the cheapest month to fly from ONT to SAN?
The cheapest flights from ONT to SAN are usually during off-peak season, when demand is lower. To save money, avoid flying during public holidays, school breaks and major local events.
Which airlines fly direct from Los Angeles - Ontario Intl. Airport (ONT) to San Diego Intl. Airport (SAN)?
You can't fly direct to San Diego Intl. Airport (SAN) from Ontario, CA (ONT-Los Angeles - Ontario Intl.). However, you can easily reach San Diego without any layovers by departing from Los Angeles Intl. Airport (LAX).
What is the cheapest airline that flies from ONT to SAN?
Use the filter tool on Expedia to compare airlines and find the cheapest carrier that'll take you from ONT to SAN. Sort your results by "Price (lowest to highest)" to snap up a great deal.
How many flights per day from Los Angeles - Ontario Intl. Airport (ONT) to San Diego Intl. Airport (SAN)?
You'll need to take a flight with a layover if you're traveling from Los Angeles - Ontario Intl. Airport (ONT) to San Diego Intl. Airport (SAN). Direct flights don't operate daily on this route. However, simply filter your search to include one or more stops to discover an option that works for you.
What day of the week has the most flights from ONT to SAN?
Friday is typically the busiest day for flights, while Tuesday is often the quietest.* Keep in mind that flight schedules can vary depending on a number of factors, such as the time of year and carrier.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What airline has the least delays from ONT to SAN?
Delta Air Lines has the best track record for on-time direct flights from Los Angeles - Ontario Intl. Airport (ONT) to San Diego Intl. Airport (SAN), with an on-time rating of 100%. Use the Expedia App to look up your journey status before you take off and get real-time alerts about any trip changes.
What is the best time to fly from Los Angeles - Ontario Intl. Airport (ONT) to San Diego Intl. Airport (SAN)?
To avoid potential delays on the Los Angeles - Ontario Intl. Airport (ONT) to San Diego Intl. Airport (SAN) route, fly before 3 PM. Departures after this hour have a 22% higher chance of cancellation.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
Is it cheaper to buy a plane ticket from Los Angeles - Ontario Intl. Airport (ONT) to San Diego Intl. Airport (SAN) last-minute?
Last-minute fares from ONT to SAN are usually more expensive. To lock in the best prices, start looking for flights as soon as possible. That being said, if you can play around with your travel dates, it's possible to find a cheap ticket right before you leave.
Is it cheaper to book an ONT to SAN flight and hotel package?
Opting for an ONT to SAN flight and hotel package is generally cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels all in one place. Choose from our wide range of hotels and then add activities, flights and car rentals to your booking. Bundle it all together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Los Angeles - Ontario Intl. Airport (ONT) to San Diego Intl. Airport (SAN)?
If you reserved your ONT to SAN flight within the last 24 hours, you may be able to cancel or modify it without any fees. Depending on the airline and the type of ticket you purchased, additional charges may apply for changes beyond that time. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal if you'd like more information.

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*Available to One Key members.