$107 Cheap Flights from Washington (IAD) to Ontario (ONT)

View $107 flight on Thu, Nov 13, 2025Opens in a new window

Popular airlines from Washington Dulles Intl. Airport (IAD) to Los Angeles - Ontario Intl. Airport (ONT)

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Cheap Flights from Washington to Ontario (IAD-ONT)

Prices were available within the past 7 days and start at $107 for one-way flights and $183 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Southwest Airlines
Tue, Sep 9 - Sat, Sep 13
IAD
Washington
ONT
Ontario
$183 Roundtrip, found 1 day ago
$183
Roundtrip
found 1 day ago
Select Southwest Airlines flight, departing Tue, Sep 9 from Washington to Ontario, returning Sat, Sep 13, priced at $183 found 1 day ago
Southwest Airlines
Tue, Sep 9 - Thu, Sep 11
IAD
Washington
ONT
Ontario
$186 Roundtrip, found 1 day ago
$186
Roundtrip
found 1 day ago
Select Southwest Airlines flight, departing Tue, Sep 9 from Washington to Ontario, returning Thu, Sep 11, priced at $186 found 1 day ago
Southwest Airlines
Mon, Sep 29 - Thu, Oct 2
IAD
Washington
ONT
Ontario
$189 Roundtrip, found 1 day ago
$189
Roundtrip
found 1 day ago
Select Southwest Airlines flight, departing Mon, Sep 29 from Washington to Ontario, returning Thu, Oct 2, priced at $189 found 1 day ago
American Airlines
Wed, Aug 6 - Tue, Aug 19
IAD
Washington
ONT
Ontario
$189 Roundtrip, found 1 day ago
$189
Roundtrip
found 1 day ago
Select American Airlines flight, departing Wed, Aug 6 from Washington to Ontario, returning Tue, Aug 19, priced at $189 found 1 day ago
Southwest Airlines
Mon, Aug 25 - Sat, Aug 30
IAD
Washington
ONT
Ontario
$190 Roundtrip, found 2 days ago
$190
Roundtrip
found 2 days ago
Select Southwest Airlines flight, departing Mon, Aug 25 from Washington to Ontario, returning Sat, Aug 30, priced at $190 found 2 days ago
Southwest Airlines
Sat, Sep 6 - Wed, Sep 10
IAD
Washington
ONT
Ontario
$191 Roundtrip, found 1 day ago
$191
Roundtrip
found 1 day ago
Select Southwest Airlines flight, departing Sat, Sep 6 from Washington to Ontario, returning Wed, Sep 10, priced at $191 found 1 day ago
American Airlines
Tue, Aug 5 - Wed, Aug 13
IAD
Washington
ONT
Ontario
$194 Roundtrip, found 1 day ago
$194
Roundtrip
found 1 day ago
Select American Airlines flight, departing Tue, Aug 5 from Washington to Ontario, returning Wed, Aug 13, priced at $194 found 1 day ago
United
Sat, Nov 1 - Tue, Nov 11
IAD
Washington
ONT
Ontario
$209 Roundtrip, found 1 day ago
$209
Roundtrip
found 1 day ago
Select United flight, departing Sat, Nov 1 from Washington to Ontario, returning Tue, Nov 11, priced at $209 found 1 day ago
Alaska Airlines
Tue, Sep 23 - Tue, Sep 30
IAD
Washington
ONT
Ontario
$234 Roundtrip, found 1 day ago
$234
Roundtrip
found 1 day ago
Select Alaska Airlines flight, departing Tue, Sep 23 from Washington to Ontario, returning Tue, Sep 30, priced at $234 found 1 day ago
Hawaiian Airlines
Wed, Aug 27 - Thu, Sep 4
IAD
Washington
ONT
Ontario
$234 Roundtrip, found 1 day ago
$234
Roundtrip
found 1 day ago
Select Hawaiian Airlines flight, departing Wed, Aug 27 from Washington to Ontario, returning Thu, Sep 4, priced at $234 found 1 day ago

Find the cheapest month to fly from Washington (IAD) to Ontario (ONT)

May is typically the cheapest month to fly

From $198 - $390 per traveler.

Graph displaying average flight prices per month

Alternative airports near Ontario

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to John Wayne SNA. Average driving time to city center is 42 minutes. Flights from $484
SNA
John Wayne
Average driving time to city center42 min
Flights from $484
Flights from Washington (IAD) to Ontario (ONT)
Origin airport
Washington Dulles Intl.
Destination airport
Los Angeles - Ontario Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Hawaiian Airlines, Southwest Airlines, United
Roundtrip price
$182
Distance
2236 mi

Washington to Ontario Flights

The cheapest times to fly from Washington to Ontario

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 Washington to Ontario are during the month of September. You can find some of the cheapest flights from Washington to Ontario with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Washington to Ontario

Sunday is one of the best days to book for cheap flights from Washington to Ontario: 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 Washington to Ontario

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 Washington to Ontario in 2025. You can also book with separate airlines for your outbound and return journeys, from $107 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 Washington to Ontario 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 Washington to Ontario 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 Washington Dulles Intl. Airport (IAD) to Los Angeles - Ontario Intl. Airport (ONT) cost?
Discover the latest flight deals from IAD to ONT 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 IAD to ONT?
The cheapest flights from IAD to ONT are usually during off-peak season, when demand is lower. To save money, avoid flying during public holidays, school breaks and major local events.
What is the cheapest airline that flies from IAD to ONT?
Use the filter tool on Expedia to compare airlines and find the cheapest carrier that'll take you from IAD to ONT. Sort your results by "Price (lowest to highest)" to snap up a great deal.
How many flights per day from Washington Dulles Intl. Airport (IAD) to Los Angeles - Ontario Intl. Airport (ONT)?
There aren't any daily direct flights from Washington Dulles Intl. Airport (IAD) to Los Angeles - Ontario Intl. Airport (ONT). But you can choose flights with layovers. Filter your search on Expedia to include one or more stops, and you'll be soaring above the clouds in no time.
What day of the week has the most flights from IAD to ONT?
Typically you'll find the largest variety of flight choices on a Friday. Tuesdays are often the quietest.* However, this can vary based on the time of year, carrier and other factors.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Washington Dulles Intl. Airport (IAD) to Los Angeles - Ontario Intl. Airport (ONT)?
To arrive at Los Angeles - Ontario Intl. Airport (ONT) without delays, opt for a flight that leaves Washington Dulles Intl. Airport (IAD) before 3 PM. The likelihood of cancellations is 22% higher, on average, for departures after this hour.**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.
What airports do you fly into for Ontario from Washington Dulles Intl. Airport (IAD)?
Los Angeles Intl. Airport (LAX) is the only airport in Ontario with direct flights from Washington Dulles Intl. Airport (IAD). Compare the options and discover affordable fares on Expedia.
Is it cheaper to buy a plane ticket from Washington Dulles Intl. Airport (IAD) to Los Angeles - Ontario Intl. Airport (ONT) last-minute?
Waiting until just before your departure to book a ticket from IAD to ONT generally means paying more. While you may find some last-minute deals, they aren't always guaranteed. Keep your travel plans flexible for a better chance of scoring a bargain.
Is it cheaper to book an IAD to ONT flight and hotel package?
Booking an IAD to ONT flight and hotel package is generally cheaper than booking separately. With Expedia, you can enjoy the convenience of organizing your trip in one place. Choose from our impressive range of hotels and then add flights, car rentals and activities 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 Washington Dulles Intl. Airport (IAD) to Los Angeles - Ontario Intl. Airport (ONT)?
If you reserved your IAD to ONT flight within the last 24 hours, you may be able to modify or cancel 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, visit our Customer Service portal for further details.

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*Available to One Key members.