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Ontario

$61+ Cheap flights from Washington, D.C. (WAS) to Ontario (ONT)

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 1/13. Fares are subject to change and may not be available on all flights or dates of travel.
WAS — ONT
Jan 17 — Jan 241
Sat 1/17
Sat 1/24
1 adult, Economy
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Find cheap flights from Washington, D.C. to Ontario 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

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3. Compare prices and book

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Cheapflights Tip: The best prices from Washington, D.C. to Ontario are usually found in April or October, booked 41 days in advance, depart on a Tuesday or Saturday and return on a Wednesday

Cheap flight deals from Washington, D.C. to Ontario

Cheapest flights from Washington, D.C. to Ontario
Explore the most affordable flight options available from Washington, D.C. to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on December 18, 2025.

This CheapOair deal was found by Cheapflights users on 12/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/229:30 pmBWI - ONT
1 stop12h 54mFrontier
Wed 12/246:20 pmONT - BWI
1 stop14h 24mFrontier
Deal found 12/16$254
This CheapOair deal was found by Cheapflights users on 12/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/219:08 pmBWI - ONT
1 stop13h 16mFrontier
Wed 12/246:20 pmONT - BWI
1 stop14h 24mFrontier
Deal found 12/16$268
This CheapOair deal was found by Cheapflights users on 12/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/219:08 pmBWI - ONT
1 stop13h 16mFrontier
Wed 12/316:20 pmONT - BWI
1 stop14h 24mFrontier
Deal found 12/16$269
This CheapOair deal was found by Cheapflights users on 12/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/219:08 pmBWI - ONT
1 stop13h 16mFrontier
Fri 1/98:31 amONT - BWI
1 stop9h 33mFrontier
Deal found 12/16$303
This CheapOair deal was found by Cheapflights users on 12/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/229:30 pmBWI - ONT
1 stop12h 54mFrontier
Mon 12/296:20 pmONT - BWI
1 stop14h 09mFrontier
Deal found 12/16$305
This CheapOair deal was found by Cheapflights users on 12/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/318:00 amDCA - ONT
1 stop18h 59mFrontier
Mon 1/56:45 amONT - DCA
1 stop12h 14mFrontier
Deal found 12/16$309
This CheapOair deal was found by Cheapflights users on 12/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/252:00 pmDCA - ONT
1 stop12h 59mFrontier
Sat 1/107:00 amONT - DCA
1 stop27h 01mFrontier
Deal found 12/16$313
This Frontier deal was found by Cheapflights users on 12/16. 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.
Sun 12/219:08 pmBWI - ONT
1 stop13h 16mFrontier
Tue 12/238:19 amONT - BWI
1 stop8h 34mFrontier
Deal found 12/16$338
This CheapOair deal was found by Cheapflights users on 12/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/318:00 amDCA - ONT
1 stop18h 59mFrontier
Sat 1/36:45 amONT - DCA
1 stop27h 16mFrontier
Deal found 12/16$358
This Frontier deal was found by Cheapflights users on 12/15. 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.
Thu 12/252:00 pmDCA - ONT
1 stop12h 59mFrontier
Mon 1/56:45 amONT - DCA
1 stop12h 14mFrontier
Deal found 12/15$363
This CheapOair deal was found by Cheapflights users on 12/15. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/298:00 amDCA - ONT
1 stop18h 59mFrontier
Thu 1/16:45 amONT - DCA
1 stop27h 16mFrontier
Deal found 12/15$364
This Trip.com deal was found by Cheapflights users on 12/17. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/252:00 pmDCA - ONT
1 stop12h 59mFrontier
Sun 1/116:00 amONT - DCA
1 stop12h 59mFrontier
Deal found 12/17$374

Find flight deals from Washington, D.C. to Ontario

Discover tips and strategies to find the most affordable flight options for your journey from Washington, D.C. (WAS) to Ontario (ONT). 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 December 18, 2025.

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$147
(Trip.com)

One-way from

$61
(Trip.com)

Popular in

November

Cheapest in

April

Average price

$386

Good one-way deal

$306 or less
Provider with most accurate pricing for Washington, D.C. (WAS)-Ontario flight deals.
Search Deals
Provider most trusted by Cheapflights users for Washington, D.C. (WAS)-Ontario flights.
Search Deals
From Washington, D.C. (WAS) to Ontario
Search Deals
One-way flight from Washington, D.C. (WAS) to Ontario
Search Deals
Highest demand for flights based on searches. 5% potential increase in price ($20 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($9 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in December 2025
Search Deals
Price to beat on a one-way flight from Washington, D.C. (WAS) to Ontario.
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Washington, D.C. to Ontario 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 December 18, 2025.
Use the filters below to find and compare flights from Washington, D.C. to Ontario that are best for you.

Fly from

Washington, D.C.

Fly to

Ontario

Route

Depart

Return

Price

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Tue 2/10

1:00 pm-9:34 pm

1 stop11h 34m

Ontario

Wed 2/11

7:30 am-9:59 pm

1 stop11h 29m

$148

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Sat 2/21

6:00 pm-7:59 am

1 stop16h 59m

Ontario

Tue 2/24

7:30 am-1:15 pm

1 stop26h 45m

$149

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Wed 1/7

6:00 pm-11:14 pm

1 stop8h 14m

Ontario

Wed 1/14

7:15 am-9:59 pm

1 stop11h 44m

$158

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Thu 1/22

2:00 pm-12:20 am

1 stop13h 20m

Ontario

Wed 1/28

7:15 am-4:59 pm

1 stop6h 44m

$165

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Sat 2/7

2:00 pm-11:24 pm

1 stop12h 24m

Ontario

Sat 2/14

6:00 am-9:59 pm

1 stop12h 59m

$165

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Wed 1/28

8:59 am-3:07 pm

1 stop9h 08m

Ontario

Wed 2/11

7:30 am-9:59 pm

1 stop11h 29m

$165

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Thu 2/5

6:00 pm-12:20 am

1 stop9h 20m

Ontario

Sat 2/7

7:15 am-9:59 pm

1 stop11h 44m

$182

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Fri 1/30

2:00 pm-12:20 am

1 stop13h 20m

Ontario

Tue 2/10

7:30 am-9:59 pm

1 stop11h 29m

$200

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Sat 1/10

2:00 pm-11:14 pm

1 stop12h 14m

Ontario

Tue 1/13

7:15 am-9:59 pm

1 stop11h 44m

$203

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Thu 2/19

6:00 pm-11:59 pm

1 stop8h 59m

Ontario

Wed 2/25

7:30 am-9:59 pm

1 stop11h 29m

$203

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/17

Showing 1-10 of 60 results
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Compare providers for flights from Washington, D.C. to Ontario

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 Washington, D.C. to Ontario in December.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy2 starsTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*1 star
eDreamsPrice Accuracy3 starsTrust Score*3 stars
Kiwi.comPrice Accuracy3 starsTrust Score*3 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 Washington, D.C.-Ontario flights, users find the pricing of eDreams to be most consistent on Cheapflights vs. eDreams Users can find the same prices on Washington, D.C.-Ontario flight deals on Cheapflights vs. eDreams >95% of the time. Price accuracy is based on data collected from Washington, D.C.-Ontario flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Washington, D.C.-Ontario flights, Cheapflights users trust eDreams the most. eDreams 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 Washington, D.C.-Ontario 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 Washington, D.C. to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from Washington, D.C. 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 Washington, D.C. to Ontario

How far ahead should I book a flight from Washington, D.C. to Ontario?

Use this chart to determine the optimal time to book a round-trip flight from Washington, D.C. to Ontario. Price data was last updated on December 12, 2025.

The best time to book flights from Washington, D.C. to Ontario is 41 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.

What is the cheapest month to book a flight from Washington, D.C. to Ontario?

Currently, January is the cheapest month in which you can book a flight from Washington, D.C. to Ontario (average of $70). Flying from Washington, D.C. to Ontario in December is currently the most expensive (average of $168). 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 WAS to ONT?

Find hourly flight availability from Washington, D.C. to Ontario. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated December 18, 2025.

It’s typically best to fly out from Washington, D.C. to Ontario in the morning. Doing so could potentially save you 24% on the flight price compared to flying at noon, which is usually more expensive.

What is the cheapest day to fly from Washington, D.C. to Ontario?

Use this chart to determine the cheapest time to fly round-trip from Washington, D.C. to Ontario. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their Washington, D.C. to Ontario flight should consider departing on Friday evenings when fares are most often at their lowest. Friday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

What’s the top layover airport for flights from Washington, D.C. to Ontario?

Share of 1-stop round-trip flights from Washington, D.C. to Ontario chosen by Cheapflights users in the past 12 months, using the same layover each way.

Denver (DEN) – chosen by Cheapflights users on 75% of 1-stop itineraries from Washington, D.C. to Ontario on Cheapflights.

What’s the cheapest layover airport for flights from Washington, D.C. to Ontario?

Average round-trip fare for 1-stop flights from Washington, D.C. to Ontario, chosen by Cheapflights users in the past 12 months, with the same layover each way.

Denver (DEN) is the most affordable 1-stop option, with an average round-trip price of $222.

What’s the fastest layover option from Washington, D.C. to Ontario?

Shortest average travel time for 1-stop one-way flights from Washington, D.C. to Ontario, based on itineraries clicked by Cheapflights users over the past 12 months, grouped by layover airport.

Flights via Denver (DEN) have the shortest average one-way travel time for 1-stop routes: 6h 55m.

Which airport typically offers the quickest layover for flights from Washington, D.C. to Ontario?

Average layover duration for 1-stop one-way flights from Washington, D.C. to Ontario, chosen by Cheapflights users in the last 12 months, grouped by stopover airport.

Flights via Denver (DEN) offer the fastest connection on this route, with an average layover time of 0h 50m.

Reviews of airlines servicing Ontario

Get insights into the airlines that provide service to Ontario. 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 Ontario. Reviews last updated December 18, 2025.
Read through reviews of airlines operating flights from Washington, D.C. to Ontario, such as Southwest, Delta, and United Airlines. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Southwest
7.9
Good
4,250 reviews

Crew

8.6

Boarding

8.1

Food

7.0

Overall

7.9

Entertainment

7.5

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Southwest
7.9
Good
4,250 reviews
Southwest
7.9
Good
4,250 reviews

Crew

8.6

Boarding

8.1

Food

7.0

Overall

7.9

Entertainment

7.5

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Delta
7.9
Good
8,005 reviews
Southwest
7.9
Good
4,250 reviews

Crew

8.6

Boarding

8.1

Food

7.0

Overall

7.9

Entertainment

7.5

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
United Airlines
7.4
Good
9,091 reviews
Southwest
7.9
Good
4,250 reviews

Crew

8.6

Boarding

8.1

Food

7.0

Overall

7.9

Entertainment

7.5

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
American Airlines
7.2
Good
11,054 reviews
Southwest
7.9
Good
4,250 reviews

Crew

8.6

Boarding

8.1

Food

7.0

Overall

7.9

Entertainment

7.5

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Frontier
5.8
Fair
3,081 reviews
Southwest
7.9
Good
4,250 reviews

Crew

8.6

Boarding

8.1

Food

7.0

Overall

7.9

Entertainment

7.5

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.

Related info for your journey

Find useful and relevant information for your journey from Washington, D.C. to Ontario. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly into for flights to Ontario from Washington, D.C.?

    Located just 3.1 mi from the city center, Ontario is the airport most travelers will use when flying to Ontario from Washington, D.C.. Booking flights from Washington, D.C. to Ontario (ONT) should be relatively easy as there are 0 daily inbound flights from Washington, D.C. from 5 different airlines.

  • How long is the flight from Washington, D.C. to Ontario?

    For as low as $312, Frontier can have you in Ontario from Washington, D.C. in 9h 26m. Washington, D.C. and Ontario are separated by a distance of 2236 mi. Both multi-stop and nonstop flights can be found to your destination and back.

  • What are the cheapest airlines flying from Washington, D.C. to Ontario round-trip?

    Cheapflights users have booked flights from Washington, D.C. to Ontario round-trip from $129. Other airlines that can offer you cheap pricing are Delta, from $213, and American Airlines, from $256. Users have found that Frontier is 65% cheaper than the other options available to this destination.

  • What are the cheapest airlines to fly from Washington, D.C. to Ontario one-way?

    The cheapest airlines for a one-way flight from Washington, D.C. to Ontario are Frontier ($75), American Airlines ($113), and United Airlines ($139).

  • What are the most popular routes from Washington, D.C. to Ontario?

    The most popular route from Washington, D.C. to Ontario is Washington, D.C. Reagan-National - Ontario. You may also consider Washington, D.C. Dulles Intl - Ontario or Baltimore/Washington - Ontario.

  • Can I find deals for flights from Washington, D.C. to Ontario that include hotel bookings?

    Yes. In addition to deals on Washington, D.C. to Ontario flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Washington, D.C. to Ontario?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Washington, D.C. to Ontario.

  • Can I find deals for business class flights from Washington, D.C. to Ontario?

    Yes. Cheapflights offers flight deals from Washington, D.C. to Ontario 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 Washington, D.C. to Ontario?

    Currently, January is the cheapest month in which you can book a flight from Washington, D.C. to Ontario (average of $70). Flying from Washington, D.C. to Ontario in December is currently the most expensive (average of $168). 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

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Alternative routes for Washington, D.C. to Ontario

See prices for flight routes from nearby airports that may be better suited for you.
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Top 5 airlines flying from Washington, D.C. to Ontario

Discover the top 5 airlines that operate flights from Washington, D.C. to Ontario. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated December 18, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$173Average$283FlexibilityNo cancel feeOn-time62%
DeltaCheapest$213Average$478FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$256Average$468FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$284Average$482FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$304Average$497FlexibilityNo cancel feeOn-time63%

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