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$99+ 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 8/19. Fares are subject to change and may not be available on all flights or dates of travel.
WAS — ONT
Aug 2 — Aug 91
Sat 8/2
Sat 8/9
1 adult, Economy
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Cheapflights Tip: The best prices from Washington, D.C. to Ontario are usually found in August or April, booked 79 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 July 28, 2025.

Round-trip from

$252
(Trip.com)

One-way from

$99
(Trip.com)

Popular in

November

Cheapest in

August

Average price

$377

Good round-trip deal

$307 or less

Good one-way deal

$168 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. 9% potential increase in price ($38 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease ($7 potential savings vs. average RT price).
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Average for round-trip flights in July 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 July 28, 2025.

This Trip.com deal was found by Cheapflights users on 7/26. 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.
Mon 8/186:00 pmDCA - ONT
1 stop8h 50mFrontier
Tue 8/1912:59 amONT - DCA
1 stop8h 12mFrontier
Deal found 7/26$252
This Frontier deal was found by Cheapflights users on 7/27. 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.
Sat 8/95:26 pmBWI - ONT
1 stop9h 24mFrontier
Tue 8/1212:59 amONT - BWI
1 stop12h 32mFrontier
Deal found 7/27$258
This Frontier deal was found by Cheapflights users on 7/27. 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.
Tue 7/297:30 amIAD - ONT
1 stop11h 50mFrontier
Tue 8/125:15 pmONT - IAD
1 stop10h 19mFrontier
Deal found 7/27$258
This Delta deal was found by Cheapflights users on 7/27. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/1912:20 pmDCA - ONT
1 stop9h 51mDelta
Sat 8/307:05 amONT - DCA
1 stop8h 47mDelta
Deal found 7/27$279
This Delta deal was found by Cheapflights users on 7/27. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/196:00 amIAD - ONT
1 stop7h 35mDelta
Tue 8/261:15 pmONT - IAD
1 stop7h 17mDelta
Deal found 7/27$279
This American Airlines deal was found by Cheapflights users on 7/26. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/197:44 amIAD - ONT
2 stops13h 08mAmerican Airlines
Tue 8/266:10 amONT - IAD
1 stop9h 46mAmerican Airlines
Deal found 7/26$284
This Alaska Airlines deal was found by Cheapflights users on 7/28. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/17:00 amIAD - ONT
1 stop10h 12mAlaska Airlines
Tue 10/216:00 amONT - IAD
1 stop9h 28mAlaska Airlines
Deal found 7/28$302
This Alaska Airlines deal was found by Cheapflights users on 7/25. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/57:38 amBWI - ONT
1 stop10h 39mAlaska Airlines
Mon 11/106:11 pmONT - BWI
1 stop9h 07mAlaska Airlines
Deal found 7/25$306
This American Airlines deal was found by Cheapflights users on 7/25. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/285:38 pmBWI - ONT
1 stop6h 50mAmerican Airlines
Mon 9/111:59 pmONT - BWI
1 stop9h 44mAmerican Airlines
Deal found 7/25$307
This Southwest deal was found by Cheapflights users on 7/26. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/248:25 amBWI - ONT
1 stop8h 35mSouthwest
Tue 9/3010:20 amONT - BWI
2 stops8h 25mSouthwest
Deal found 7/26$312
This Delta deal was found by Cheapflights users on 7/28. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/65:40 amBWI - ONT
1 stop7h 55mDelta
Sat 9/137:05 amONT - BWI
1 stop7h 13mDelta
Deal found 7/28$327
This United Airlines deal was found by Cheapflights users on 7/27. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/2310:10 amBWI - ONT
2 stops13h 23mUnited Airlines
Wed 8/276:04 amONT - BWI
1 stop7h 13mUnited Airlines
Deal found 7/27$342

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 July 28, 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

Mon 8/18

6:00 pm-11:50 pm

1 stop8h 50m

Ontario

Tue 8/19

12:59 am-12:11 pm

1 stop8h 12m

$252

BaltimoreOntario

BWI - ONT

BWIONT

Baltimore/Washington

Sat 8/9

5:26 pm-11:50 pm

1 stop9h 24m

Ontario

Tue 8/12

12:59 am-4:31 pm

1 stop12h 32m

$258

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 8/5

7:30 am-4:20 pm

1 stop11h 50m

Ontario

Sat 8/9

5:13 pm-6:34 am

1 stop10h 21m

$258

Washington, D.C.Ontario

DCA - ONT

DCAONT

Washington, D.C. Reagan-National

Tue 8/19

12:20 pm-7:11 pm

1 stop9h 51m

Ontario

Sat 8/30

7:05 am-6:52 pm

1 stop8h 47m

$279

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 8/19

3:26 pm-10:20 pm

1 stop9h 54m

Ontario

Wed 8/27

6:05 pm-5:55 am

1 stop8h 50m

$279

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 8/19

7:44 am-5:52 pm

2 stops13h 08m

Ontario

Tue 8/26

6:10 am-6:56 pm

1 stop9h 46m

$284

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Wed 10/1

7:00 am-2:12 pm

1 stop10h 12m

Ontario

Tue 10/21

6:00 am-6:28 pm

1 stop9h 28m

$302

BaltimoreOntario

BWI - ONT

BWIONT

Baltimore/Washington

Thu 8/28

5:38 pm-9:28 pm

1 stop6h 50m

Ontario

Mon 9/1

11:59 pm-12:43 pm

1 stop9h 44m

$307

BaltimoreOntario

BWI - ONT

BWIONT

Baltimore/Washington

Wed 9/24

8:25 am-2:00 pm

1 stop8h 35m

Ontario

Tue 9/30

10:20 am-9:45 pm

2 stops8h 25m

$312

BaltimoreOntario

BWI - ONT

BWIONT

Baltimore/Washington

Wed 9/17

7:00 am-2:12 pm

1 stop10h 12m

Ontario

Wed 9/24

3:06 pm-5:39 am

1 stop11h 33m

$326

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/26

Showing 1-10 of 34 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 July 25, 2025.

The best time to book flights from Washington, D.C. to Ontario is 77 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 July 28, 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 88% 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 $273.

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: 4h 05m.

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 3h 48m.

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 July 28, 2025.
Read through reviews of airlines operating flights from Washington, D.C. to Ontario, such as Alaska Airlines, Southwest, and Delta. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Food

7.1

Entertainment

7.1

Boarding

8.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Food

7.1

Entertainment

7.1

Boarding

8.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Southwest
8.0
Very good
4,238 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Food

7.1

Entertainment

7.1

Boarding

8.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Delta
8.0
Very good
7,975 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Food

7.1

Entertainment

7.1

Boarding

8.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Hawaiian Airlines
7.8
Good
2,604 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Food

7.1

Entertainment

7.1

Boarding

8.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
United Airlines
7.4
Good
8,892 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Food

7.1

Entertainment

7.1

Boarding

8.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

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 popular is this Washington, D.C. to Ontario flight route?

    This flight path from Washington, D.C. to Ontario was viewed by 1 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

  • 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 $252. Other airlines that can offer you cheap pricing are Delta, from $279, and American Airlines, from $284. Users have found that Frontier is 34% 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 ($99), Hawaiian Airlines ($139), and American Airlines ($140).

  • 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.

  • What are the cheapest flights from Washington, D.C. to Ontario?

    The cheapest flight price from Washington, D.C. to Ontario is $102. On average you can expect to pay $295. The most popular route, (Washington, D.C. Dulles Intl - Ontario), can usually be booked for $267.

  • 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 July 28, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$148Average$275FlexibilityNo cancel feeOn-time62%
DeltaCheapest$286Average$415FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$286Average$454FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$310Average$517FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$326Average$498FlexibilityNo cancel feeOn-time63%

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