£119 Cheap Flights from Washington (IAD) to Ontario (ONT)

View £119 flight on Tue, 14 Jul 2026Opens in a new window

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

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

Prices were available within the past 7 days and start at £119 for one-way flights and £237 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Alaska Airlines
Wed, 27 May - Tue, 9 Jun
IAD
Washington
ONT
Ontario
£237 Return, found 2 days ago
£237
Return
found 2 days ago
Select Alaska Airlines flight, departing Wed, 27 May from Washington to Ontario, returning Tue, 9 Jun, priced at £237 found 2 days ago
American Airlines
Tue, 14 Jul - Mon, 20 Jul
IAD
Washington
ONT
Ontario
£252 Return, found 3 days ago
£252
Return
found 3 days ago
Select American Airlines flight, departing Tue, 14 Jul from Washington to Ontario, returning Mon, 20 Jul, priced at £252 found 3 days ago
Alaska Airlines
Thu, 28 May - Wed, 10 Jun
IAD
Washington
ONT
Ontario
£266 Return, found 2 days ago
£266
Return
found 2 days ago
Select Alaska Airlines flight, departing Thu, 28 May from Washington to Ontario, returning Wed, 10 Jun, priced at £266 found 2 days ago
Alaska Airlines
Tue, 12 May - Fri, 29 May
IAD
Washington
ONT
Ontario
£268 Return, found 2 days ago
£268
Return
found 2 days ago
Select Alaska Airlines flight, departing Tue, 12 May from Washington to Ontario, returning Fri, 29 May, priced at £268 found 2 days ago
American Airlines
Tue, 14 Jul - Mon, 20 Jul
IAD
Washington
ONT
Ontario
£289 Return, found 3 days ago
£289
Return
found 3 days ago
Select American Airlines flight, departing Tue, 14 Jul from Washington to Ontario, returning Mon, 20 Jul, priced at £289 found 3 days ago
Alaska Airlines
Wed, 13 May - Wed, 27 May
IAD
Washington
ONT
Ontario
£293 Return, found 2 days ago
£293
Return
found 2 days ago
Select Alaska Airlines flight, departing Wed, 13 May from Washington to Ontario, returning Wed, 27 May, priced at £293 found 2 days ago
Alaska Airlines
Mon, 1 Jun - Tue, 16 Jun
IAD
Washington
ONT
Ontario
£307 Return, found 2 days ago
£307
Return
found 2 days ago
Select Alaska Airlines flight, departing Mon, 1 Jun from Washington to Ontario, returning Tue, 16 Jun, priced at £307 found 2 days ago
Alaska Airlines
Wed, 13 May - Fri, 29 May
IAD
Washington
ONT
Ontario
£308 Return, found 2 days ago
£308
Return
found 2 days ago
Select Alaska Airlines flight, departing Wed, 13 May from Washington to Ontario, returning Fri, 29 May, priced at £308 found 2 days ago
Alaska Airlines
Sat, 16 May - Wed, 3 Jun
IAD
Washington
ONT
Ontario
£335 Return, found 2 days ago
£335
Return
found 2 days ago
Select Alaska Airlines flight, departing Sat, 16 May from Washington to Ontario, returning Wed, 3 Jun, priced at £335 found 2 days ago
Delta
Tue, 12 May - Wed, 13 May
IAD
Washington
ONT
Ontario
£337 Return, found 2 days ago
£337
Return
found 2 days ago
Select Delta flight, departing Tue, 12 May from Washington to Ontario, returning Wed, 13 May, priced at £337 found 2 days ago

Alternative airports near Ontario

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

Select flight to Los Angeles - Ontario Intl. ONT. Cheapest and Closest option available. Average driving time to city centre is 8 minutes. Flights from £236
ONT
Los Angeles - Ontario Intl.
CheapestClosest
Average driving time to city centre8 min
Flights from £236

Frequently asked questions

How much is a flight from Washington Dulles Intl. Airport (IAD) to Los Angeles - Ontario Intl. Airport (ONT)?
Within the past 7 days on Expedia, for flights departing within the next year, the lowest price quoted for a round-trip flight from Washington Dulles Intl. Airport (IAD) to Los Angeles - Ontario Intl. Airport (ONT) was £237. Cheap tickets don't last long, so make sure you book yours ASAP. Prices and availability are subject to change. Additional terms apply.
Do I need to pay a cancellation fee if I cancel my flight from IAD to ONT?
The majority of flights can be cancelled online, but each air carrier has different terms and conditions. If you do decide to cancel your flight, check out our Customer Service Portal and follow the instructions.
How do I find cheap flights from IAD to Los Angeles - Ontario Intl. Airport (ONT) that have flexible change policies?
Many airlines offer the option to reschedule your flight without a change fee. All you pay is the difference between the original flight and the new flight. When you're searching for IAD to ONT flights, you'll see a "no change fees" filter for you to select.
How far is the flight from IAD to Los Angeles - Ontario Intl. Airport (ONT)?
Expect to be in the air for a while, as the flight distance between Chantilly and Ontario is 3,600 kilometres. Create a playlist of your favourite songs before leaving home to keep yourself entertained during the trip.
Which airlines fly direct from Washington Dulles Intl. Airport (IAD) to Ontario Airport?
You won't find any airlines operating directly between Dulles Intl. Airport and Los Angeles - Ontario Intl. Airport (ONT), so be prepared to make at least one stop on your journey. A layover, whether short or long, can be a welcome way to break up a trip!
Are Dulles Intl. Airport to ONT flight tickets cheaper when they're purchased at the last minute?
Flight tickets from IAD to Los Angeles - Ontario Intl. Airport (ONT) are available up to a year prior to departure on Expedia. And although you may occasionally score a great last-minute deal, it's not something you should bank on. Also, booking your flights well in advance means you'll have more choices — and you can avoid ending up with the dreaded middle seat! We're constantly updating our fares to bring you the best bargains, so keep checking in for all the latest specials.

Frequently asked questions

What is the cheapest month to fly from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?
October is typically the cheapest month to fly from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.), with average return fares of approximately £275. This is about 21% lower than the average price throughout the year. October often sees lower prices as the summer travel rush has ended and before the winter holiday season begins, leading to reduced demand. Other cheap months to fly from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) include April and September.
How do I find cheap flights from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?
To find a cheap flight from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.), be flexible with your dates. Traveling outside of peak vacation months and booking a mid-week flight can help you save. Early morning and late night flights are often more affordable, too. Expedia allows you to compare flight times, airlines and routes all in one place to find low fares. You can also set up Price Tracking and receive alerts when fares go up or down.
What is the best time to fly from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?
Based on booking data from the past year, the cheapest months to fly from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) are typically October and September, with average return flights around £275. These months are ideal if you're looking for the best value, allowing you to save on your airfare.
How many flights per day from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?
There are approximately 52 connecting flights per day from Washington Dulles Intl. (IAD) to Los Angeles - Ontario Intl. (ONT). Some common connection points include Seattle - Tacoma Intl. (SEA), Denver Intl. (DEN), and San Diego Intl. (SAN).
What is the earliest flight from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?
The earliest flight from Washington Dulles Intl. (IAD) to Los Angeles - Ontario Intl. (ONT) typically departs at approximately 5:00 AM local time, operated by American Airlines. This is a seasonal service active in August. An early departure like this can help maximise your time at your destination. To compare early flights on Expedia, select the "Early Morning" and "Morning" filters in your search.
What day of the week has the most flights from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?
You'll typically find the most flights from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) on a Friday, with around 32 flights available. This gives you plenty of options for your travel plans. Major airlines on this route include United Airlines, Delta Air Lines, and American Airlines. Flight options are notably more on Fridays compared to other days of the week.
What are the most popular departure times for flights from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?
The most popular departure times for flights from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) are in the early morning, from 6am to 9am. About 36% of passengers prefer this time. Many major carriers, including Delta, United and American Airlines, offer flights during this window. This timing works well because you can get an early start to your travel day and arrive at your destination with plenty of time.
How long does it take to fly from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?
Flights from IAD to ONT with one stop typically take around 7 hours 30 minutes, covering approximately 2,237 miles. Keep in mind that actual flight times can vary due to wind patterns, weather, and air traffic.
Can you fly business or first class from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?
Select the "Business class" and "First class" filters when looking for IAD to ONT flights on Expedia. This is the easiest way to compare prices, routes and flight times for your trip.
How do I earn miles on a Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) flight with Expedia?
It's easy to earn miles on a Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) flight when you book with Expedia. Before you confirm your booking, simply select your frequent flyer program and enter your program number. As a member of One Key™, you can also earn OneKeyCash™* on top of your airline miles when you book with Expedia. *Excludes taxes and fees. OneKeyCash is not redeemable for cash and can only be used on Expedia and other participating brands.
What airports do you fly into for Ontario from Washington Dulles Intl. (IAD)?
From Washington Dulles Intl. (IAD), you can fly directly into Los Angeles - Ontario Intl. (ONT) to reach Ontario. Some flights may connect through major hubs like Seattle - Tacoma Intl. (SEA), San Diego Intl. (SAN), O'Hare Intl. (ORD) before reaching Ontario. Compare routes and airports on Expedia to find the best flight options for your travel plans.
Is it cheaper to buy a plane ticket from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) at the last minute?
Typically, booking a last minute flight from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) will be more expensive than booking in advance. As the departure date approaches, there are usually fewer seats available which can drive up the cost. However, if there's some wiggle room with your travel dates and times, you could bag a cheap last-minute fare.
Is it cheaper to book a Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) flight and hotel package?
Securing a Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) flight and hotel package is usually cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels all in one place. Select from our extensive range of stays and then add flights, activities and car rentals to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?
If you booked your Washington, DC (IAD-Washington Dulles Intl.) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) 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 have, additional charges may apply for changes beyond this timeframe. 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.

Travel information

Origin airport
Washington Dulles Intl.
Destination airport
Los Angeles - Ontario Intl.
Return price
£236
Distance
3578 km

Book with confidence

Compare flights from Washington to Ontario easily and book with confidence

For travelling on business or for pleasure, Expedia makes it easy to book your flights from Washington to Ontario. Operating between them flights per day, 20 airlines cover the route. And fly direct, getting you to Los Angeles - Ontario Intl. in just hours. If you have a preferred carrier, use our advanced search tool to find the right flight from Washington Dulles Intl. to Los Angeles - Ontario Intl..  

To make things even better, in the advanced search, you can also choose to fly economy, premium economy, business or first class, select your maximum number of stops, and pick your preferred departure and arrival time. You can also opt for refundable and direct flights. 

Grab a great deal on your flight from Washington Dulles Intl. (IAD) to Los Angeles - Ontario Intl. (ONT)

The easiest way to view the best deals on flights from Washington to Ontario today is to enter your travel dates and hit search. From here, you can sort your results by price to see the cheapest flights first. Right now, return flights from Washington Dulles Intl. to Los Angeles - Ontario Intl. start at just £237 and range up to £337.  

To find an even better deal, try  

  • being flexible on your dates – midweek flights can be cheaper
  • looking for other airports near Washington and Ontario
  • booking your flight during May, the cheapest month on this route
  • varying your flight times – early morning and late at night are sometimes cheaper 

Why you should book your Washington to Ontario flight with Expedia!

We cater for all flight types, cabin classes and airlines. So whether you’re booking flights from Washington Dulles Intl. to Los Angeles - Ontario Intl. for a budget break or a business trip with a bit of pleasure thrown in, we make it easy to secure the seat that’s right for you.  

Thanks to our supersized inventory that offers great choice all in one place, you know you’ll get a great deal with Expedia. Especially if you bundle your flight together with your hotel, you will unlock amazing savings. For added peace of mind, you can choose flexible bookings or filter to find refundable options, so you won’t pay a fee to change your flight.  

Compare flights from Washington to Ontario easily and book with confidence

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