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$88+ 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 11/3. Fares are subject to change and may not be available on all flights or dates of travel.
WAS — ONT
Oct 15 — Oct 221
Wed 10/15
Wed 10/22
1 adult, Economy
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Cheapflights Tip: The best prices from Washington, D.C. to Ontario are usually found in April or October, booked 71 days in advance, depart on a Tuesday or Saturday and return on a Wednesday

Cheap 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 September 15, 2025.

Round-trip from

$161
(Priceline)

One-way from

$88
(United Airlines)

Popular in

December

Cheapest in

April

Average price

$361

Good round-trip deal

$358 or less

Good one-way deal

$176 or less
From Washington, D.C. (WAS) to Ontario
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One-way flight from Washington, D.C. (WAS) to Ontario
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Highest demand for flights based on searches. 11% potential increase in price ($49 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease ($6 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Price to beat on a round-trip flight from Washington, D.C. (WAS) to Ontario.
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Price to beat on a one-way flight from Washington, D.C. (WAS) to Ontario.
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Find 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 September 15, 2025.

This Priceline deal was found by Cheapflights users on 9/13. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/2810:17 amIAD - ONT
1 stop8h 07mFrontier
Sun 9/287:15 pmONT - IAD
1 stop11h 02mFrontier
Deal found 9/13$161
This Booking.com deal was found by Cheapflights users on 9/13. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/2810:17 amIAD - ONT
1 stop10h 58mFrontier
Thu 10/24:34 pmONT - IAD
1 stop13h 43mFrontier
Deal found 9/13$162
This Booking.com deal was found by Cheapflights users on 9/14. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/210:17 amIAD - ONT
1 stop8h 22mFrontier
Sun 10/54:09 pmONT - IAD
1 stop14h 08mFrontier
Deal found 9/14$163
This Booking.com deal was found by Cheapflights users on 9/13. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/36:27 pmBWI - ONT
1 stop28h 27mFrontier
Sun 10/58:59 pmONT - BWI
1 stop17h 43mFrontier
Deal found 9/13$166
This Booking.com deal was found by Cheapflights users on 9/13. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/249:42 pmBWI - ONT
1 stop13h 07mFrontier
Sun 10/266:53 amONT - BWI
1 stop7h 51mFrontier
Deal found 9/13$167
This Mytrip deal was found by Cheapflights users on 9/14. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/11:00 pmDCA - ONT
1 stop9h 54mFrontier
Tue 10/147:04 amONT - DCA
1 stop26h 00mFrontier
Deal found 9/14$167
This Gotogate deal was found by Cheapflights users on 9/14. 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 Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/12:00 pmDCA - ONT
1 stop12h 50mFrontier
Sat 11/86:53 amONT - DCA
1 stop7h 06mFrontier
Deal found 9/14$168
This Booking.com deal was found by Cheapflights users on 9/13. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/286:00 pmDCA - ONT
1 stop16h 53mFrontier
Mon 9/298:59 pmONT - DCA
1 stop22h 00mFrontier
Deal found 9/13$169
This Gotogate deal was found by Cheapflights users on 9/14. 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 Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/2510:17 amIAD - ONT
1 stop8h 12mFrontier
Thu 10/24:34 pmONT - IAD
1 stop13h 43mFrontier
Deal found 9/14$174
This Frontier deal was found by Cheapflights users on 9/13. 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.
Fri 10/249:42 pmBWI - ONT
1 stop13h 07mFrontier
Mon 10/276:53 amONT - BWI
1 stop7h 51mFrontier
Deal found 9/13$175
This Booking.com deal was found by Cheapflights users on 9/13. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/2510:17 amIAD - ONT
1 stop8h 12mFrontier
Sun 9/287:15 pmONT - IAD
1 stop11h 02mFrontier
Deal found 9/13$175
This Frontier deal was found by Cheapflights users on 9/14. 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 10/309:58 pmBWI - ONT
1 stop12h 31mFrontier
Mon 11/38:24 amONT - BWI
1 stop7h 34mFrontier
Deal found 9/14$176

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 September 15, 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

Sat 11/1

6:00 pm-11:50 pm

1 stop8h 50m

Ontario

Sat 11/8

6:53 am-4:59 pm

1 stop7h 06m

$168

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Mon 9/29

6:00 pm-7:54 pm

1 stop28h 54m

Ontario

Wed 10/1

8:59 pm-9:59 pm

1 stop22h 00m

$169

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Wed 10/8

7:00 am-9:35 am

1 stop29h 35m

Ontario

Wed 10/15

6:53 am-12:04 pm

1 stop26h 11m

$169

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Fri 10/17

6:31 pm-11:50 pm

1 stop8h 19m

Ontario

Sat 10/25

7:04 am-4:59 pm

1 stop6h 55m

$177

BaltimoreOntario

BWI - ONT

BWIONT

Baltimore/Washington

Sat 10/25

4:21 pm-8:24 pm

1 stop7h 03m

Ontario

Wed 11/19

6:38 pm-9:59 am

2 stops12h 21m

$190

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Fri 11/14

1:00 pm-11:50 pm

1 stop13h 50m

Ontario

Tue 11/18

6:53 am-4:59 pm

1 stop7h 06m

$213

BaltimoreOntario

BWI - ONT

BWIONT

Baltimore/Washington

Fri 11/14

6:21 pm-11:04 pm

1 stop7h 43m

Ontario

Tue 11/18

10:25 pm-11:10 am

1 stop9h 45m

$277

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Sat 11/1

6:00 am-10:26 am

1 stop7h 26m

Ontario

Sat 11/8

11:36 am-9:43 pm

1 stop7h 07m

$277

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Fri 10/31

7:35 am-2:01 pm

1 stop9h 26m

Ontario

Tue 11/4

11:48 am-12:40 am

1 stop9h 52m

$277

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 10/14

7:35 am-5:10 pm

1 stop12h 35m

Ontario

Wed 10/15

11:48 am-12:40 am

1 stop9h 52m

$277

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/14

Showing 1-10 of 60 results
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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 September 12, 2025.

The best time to book flights from Washington, D.C. to Ontario is 71 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, August is the cheapest month in which you can book a flight from Washington, D.C. to Ontario (average of $246). Flying from Washington, D.C. to Ontario in March is currently the most expensive (average of $328). 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 September 15, 2025.

It’s typically best to fly out from Washington, D.C. to Ontario in the afternoon. Doing so could potentially save you 16% on the flight price compared to flying in the evening, 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 Saturday evenings when fares are most often at their lowest. Friday evenings 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 80% 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: 7h 32m.

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 1h 34m.

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 September 15, 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
8.0
Very good
4,242 reviews

Food

7.0

Crew

8.6

Overall

8.0

Boarding

8.1

Comfort

8.0

Entertainment

7.5

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
8.0
Very good
4,242 reviews
Southwest
8.0
Very good
4,242 reviews

Food

7.0

Crew

8.6

Overall

8.0

Boarding

8.1

Comfort

8.0

Entertainment

7.5

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
8.0
Very good
7,954 reviews
Southwest
8.0
Very good
4,242 reviews

Food

7.0

Crew

8.6

Overall

8.0

Boarding

8.1

Comfort

8.0

Entertainment

7.5

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
8,929 reviews
Southwest
8.0
Very good
4,242 reviews

Food

7.0

Crew

8.6

Overall

8.0

Boarding

8.1

Comfort

8.0

Entertainment

7.5

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
10,000 reviews
Southwest
8.0
Very good
4,242 reviews

Food

7.0

Crew

8.6

Overall

8.0

Boarding

8.1

Comfort

8.0

Entertainment

7.5

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
3,172 reviews
Southwest
8.0
Very good
4,242 reviews

Food

7.0

Crew

8.6

Overall

8.0

Boarding

8.1

Comfort

8.0

Entertainment

7.5

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 $190, Frontier can have you in Ontario from Washington, D.C. in 7h 03m. Washington, D.C. and Ontario are separated by a distance of 2276 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 $150. Other airlines that can offer you cheap pricing are Delta, from $213, and United Airlines, from $284. Users have found that Frontier is 60% 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 United Airlines ($93), Hawaiian Airlines ($138), and Delta ($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. Dulles Intl - Ontario. You may also consider Baltimore/Washington - Ontario or Washington, D.C. Reagan-National - 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, August is the cheapest month in which you can book a flight from Washington, D.C. to Ontario (average of $246). Flying from Washington, D.C. to Ontario in March is currently the most expensive (average of $328). 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 September 15, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$150Average$275FlexibilityNo cancel feeOn-time62%
DeltaCheapest$213Average$412FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$218Average$507FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$296Average$475FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$296Average$502FlexibilityNo cancel feeOn-time63%

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