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$80+ Cheap flights from Dulles Intl (IAD) 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 5/26. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — ONT
May 19 — May 261
Tue 5/19
Tue 5/26
1 adult, Economy
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Cheap flight deals from Dulles Intl to Ontario

Cheapest flights from Dulles Intl to Ontario
Explore the most affordable flight options available from Dulles Intl to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on April 19, 2026.

This Frontier deal was found by Cheapflights users on 4/17. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/712:36 pm
IAD
-
ONT
1 stop9h 35m
Frontier
Wed 5/204:39 pm
ONT
-
IAD
1 stop12h 33m
Frontier
Deal found 4/17$180
This Frontier deal was found by Cheapflights users on 4/18. 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 5/269:12 am
IAD
-
ONT
1 stop9h 32m
Frontier
Wed 6/34:39 pm
ONT
-
IAD
1 stop12h 33m
Frontier
Deal found 4/18$185
This Frontier deal was found by Cheapflights users on 4/17. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/269:12 am
IAD
-
ONT
1 stop9h 32m
Frontier
Thu 5/283:30 pm
ONT
-
IAD
1 stop13h 42m
Frontier
Deal found 4/17$190
This CheapOair deal was found by Cheapflights users on 4/15. 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.
Tue 5/269:12 am
IAD
-
ONT
1 stop9h 32m
Frontier
Tue 6/91:33 pm
ONT
-
IAD
1 stop15h 52m
Frontier
Deal found 4/15$196
This Booking.com deal was found by Cheapflights users on 4/16. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/269:12 am
IAD
-
ONT
1 stop9h 32m
Frontier
Sat 5/303:30 pm
ONT
-
IAD
1 stop13h 42m
Frontier
Deal found 4/16$197
This CheapOair deal was found by Cheapflights users on 4/17. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/259:12 am
IAD
-
ONT
1 stop25h 52m
Frontier
Mon 6/13:30 pm
ONT
-
IAD
1 stop13h 42m
Frontier
Deal found 4/17$201
This Frontier deal was found by Cheapflights users on 4/18. 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 5/1012:36 pm
IAD
-
ONT
1 stop9h 35m
Frontier
Wed 5/204:39 pm
ONT
-
IAD
1 stop12h 33m
Frontier
Deal found 4/18$205
This Mytrip deal was found by Cheapflights users on 4/15. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 6/99:55 am
IAD
-
ONT
1 stop12h 56m
Frontier
Tue 6/163:34 pm
ONT
-
IAD
1 stop13h 51m
Frontier
Deal found 4/15$210
This Booking.com deal was found by Cheapflights users on 4/14. 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.
Tue 5/269:12 am
IAD
-
ONT
1 stop9h 32m
Frontier
Fri 5/2911:51 am
ONT
-
IAD
1 stop17h 21m
Frontier
Deal found 4/14$212
This CheapOair deal was found by Cheapflights users on 4/16. 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.
Fri 5/299:12 am
IAD
-
ONT
1 stop25h 52m
Frontier
Tue 6/21:39 pm
ONT
-
IAD
1 stop15h 33m
Frontier
Deal found 4/16$215
This Gotogate deal was found by Cheapflights users on 4/18. 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.
Wed 6/39:12 am
IAD
-
ONT
1 stop9h 32m
Frontier
Wed 6/101:33 pm
ONT
-
IAD
1 stop15h 52m
Frontier
Deal found 4/18$216

Find flight deals from Dulles Intl to Ontario

Discover tips and strategies to find the most affordable flight options for your journey from Dulles Intl (IAD) 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 April 19, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$180
(Frontier)

One-way from

$80
(Frontier)

Popular in

November

Cheapest in

September

Average price

$448
Provider with most accurate pricing for Washington, D.C. Dulles Intl-Ontario flight deals.
Search Deals
Provider most trusted by Cheapflights users for Washington, D.C. Dulles Intl-Ontario flights.
Search Deals
From Washington, D.C. Dulles Intl to Ontario
Search Deals
One-way flight from Washington, D.C. Dulles Intl to Ontario
Search Deals
Highest demand for flights based on searches. 20% potential increase in price ($112 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease ($21 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in April 2026
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Dulles Intl 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 April 19, 2026.
Use the filters below to find and compare flights from Washington, D.C. Dulles Intl Airport to Ontario that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 5/5

7:10 am-2:32 pm

1 stop10h 22m

Ontario

Wed 5/6

10:39 am-12:09 am

1 stop10h 30m

$321

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Fri 6/5

6:08 am-10:57 am

1 stop7h 49m

Ontario

Tue 6/9

11:57 am-12:25 am

1 stop9h 28m

$341

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 5/12

7:10 am-2:32 pm

1 stop10h 22m

Ontario

Tue 5/19

12:04 pm-11:59 pm

1 stop8h 55m

$341
Quickest round-trip

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Fri 5/8

7:30 am-12:19 pm

1 stop7h 49m

Ontario

Fri 5/8

10:00 pm-9:58 am

1 stop8h 58m

$430

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Sat 7/11

2:53 pm-9:55 pm

1 stop10h 02m

Ontario

Sat 7/18

1:18 pm-12:45 am

1 stop8h 27m

$451

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 4/28

7:10 am-2:32 pm

1 stop10h 22m

Ontario

Tue 5/5

10:39 am-12:09 am

1 stop10h 30m

$485

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 7/2

3:30 pm-10:51 pm

1 stop10h 21m

Ontario

Mon 7/6

5:45 am-6:50 pm

1 stop10h 05m

$501

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 5/5

8:20 am-9:58 pm

2 stops16h 38m

Ontario

Wed 5/6

6:59 pm-6:00 am

1 stop8h 01m

$514

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Wed 5/20

6:00 am-3:09 pm

1 stop12h 09m

Ontario

Fri 5/22

7:41 pm-7:34 am

1 stop8h 53m

$533

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 6/4

6:00 am-3:09 pm

1 stop12h 09m

Ontario

Thu 6/4

7:41 pm-7:34 am

1 stop8h 53m

$533

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/18

Showing 1-10 of 23 resultsSorted by cheapest first
1
2
3

Compare providers for flights from Dulles Intl 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 Dulles Intl to Ontario in April.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
PricelinePrice Accuracy1 starTrust 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. Dulles Intl Airport-Ontario flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Washington, D.C. Dulles Intl Airport-Ontario flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Washington, D.C. Dulles Intl Airport-Ontario flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Washington, D.C. Dulles Intl Airport-Ontario flights, Cheapflights users trust FlightHub the most. FlightHub 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. Dulles Intl Airport-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 Dulles Intl to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from Dulles Intl 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. Dulles Intl Airport to Ontario

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

Currently, September is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to Ontario (average of $273). Flying from Washington, D.C. Dulles Intl Airport to Ontario in November is currently the most expensive (average of $661). 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.

How much does it cost to fly round-trip from Washington, D.C. Dulles Intl Airport to Ontario?

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 April 19, 2026.
Read reviews from past customers who have flown Southwest,Delta, andUnited Airlines from Washington, D.C. Dulles Intl Airport to Ontario. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,328 reviews

Boarding

8.1

Crew

8.6

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Dominic,Mar 2026

MCO - SMF

I had to try and sleep on the floor of the Austin airport. I spent 12 hours there. The airline policies were so poor, that a near violent argument broke out between the people in front of me and the flight attendants - making for a super stressful situation at 30,000 feet. Garbage airline choice by Kayak Garbage idea to book a flight with a layover. Next time I will pay for a quality booking myself, and somehow force the company to reimburse it.
Southwest
8.0
Very good
4,328 reviews
Southwest
8.0
Very good
4,328 reviews

Boarding

8.1

Crew

8.6

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Dominic,Mar 2026

MCO - SMF

I had to try and sleep on the floor of the Austin airport. I spent 12 hours there. The airline policies were so poor, that a near violent argument broke out between the people in front of me and the flight attendants - making for a super stressful situation at 30,000 feet. Garbage airline choice by Kayak Garbage idea to book a flight with a layover. Next time I will pay for a quality booking myself, and somehow force the company to reimburse it.
Delta
7.9
Good
8,422 reviews
Southwest
8.0
Very good
4,328 reviews

Boarding

8.1

Crew

8.6

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Dominic,Mar 2026

MCO - SMF

I had to try and sleep on the floor of the Austin airport. I spent 12 hours there. The airline policies were so poor, that a near violent argument broke out between the people in front of me and the flight attendants - making for a super stressful situation at 30,000 feet. Garbage airline choice by Kayak Garbage idea to book a flight with a layover. Next time I will pay for a quality booking myself, and somehow force the company to reimburse it.
United Airlines
7.4
Good
9,605 reviews
Southwest
8.0
Very good
4,328 reviews

Boarding

8.1

Crew

8.6

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Dominic,Mar 2026

MCO - SMF

I had to try and sleep on the floor of the Austin airport. I spent 12 hours there. The airline policies were so poor, that a near violent argument broke out between the people in front of me and the flight attendants - making for a super stressful situation at 30,000 feet. Garbage airline choice by Kayak Garbage idea to book a flight with a layover. Next time I will pay for a quality booking myself, and somehow force the company to reimburse it.
American Airlines
7.1
Good
11,621 reviews
Southwest
8.0
Very good
4,328 reviews

Boarding

8.1

Crew

8.6

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Dominic,Mar 2026

MCO - SMF

I had to try and sleep on the floor of the Austin airport. I spent 12 hours there. The airline policies were so poor, that a near violent argument broke out between the people in front of me and the flight attendants - making for a super stressful situation at 30,000 feet. Garbage airline choice by Kayak Garbage idea to book a flight with a layover. Next time I will pay for a quality booking myself, and somehow force the company to reimburse it.
Frontier
5.7
Fair
2,985 reviews
Southwest
8.0
Very good
4,328 reviews

Boarding

8.1

Crew

8.6

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Dominic,Mar 2026

MCO - SMF

I had to try and sleep on the floor of the Austin airport. I spent 12 hours there. The airline policies were so poor, that a near violent argument broke out between the people in front of me and the flight attendants - making for a super stressful situation at 30,000 feet. Garbage airline choice by Kayak Garbage idea to book a flight with a layover. Next time I will pay for a quality booking myself, and somehow force the company to reimburse it.

Related info for your journey

Find useful and relevant information for your journey from Dulles Intl 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. Dulles Intl?

    Ontario (ONT), located 3.1 mi from the city center, is the airport you fly into when you book flights from Washington, D.C. Dulles Intl to Ontario. 5 airlines have flights to Ontario from Washington, D.C. Dulles Intl on a regular basis. Booking flights from Washington, D.C. Dulles Intl to Ontario should not be difficult; the airport handles an average of 0 inbound flights from Washington, D.C. Dulles Intl per day.

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

    For as low as $341, Alaska Airlines can have you in Ontario from Washington, D.C. Dulles Intl Airport in 7h 49m. The distance between Washington, D.C. Dulles Intl Airport and Ontario is about 2236 mi. This flight may include one or multiple stops.

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

    Our cheapest airline available from Washington, D.C. Dulles Intl Airport to Ontario is Frontier. Our recent data shows that you can find tickets from as low as $125 on this airline. Additional options worth looking into are Delta and United Airlines, starting at $213 and $269 round-trip. Frontier is priced at 71% lower than the current average price of a flight leaving 3 months from now.

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

    The cheapest airline one-way is Frontier, with whom users have recently found tickets for as low as $99. However, be on the lookout for offers from United Airlines and Delta, as they are both options that can get you from Washington, D.C. Dulles Intl Airport to Ontario for a low price.

  • Can I find deals for flights from Dulles Intl to Ontario that include hotel bookings?

    Yes. In addition to deals on Dulles Intl to Ontario flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Dulles Intl to Ontario?

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

  • Can I find deals for business class flights from Dulles Intl to Ontario?

    Yes. Cheapflights offers flight deals from Dulles Intl 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. Dulles Intl Airport to Ontario?

    Currently, September is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to Ontario (average of $273). Flying from Washington, D.C. Dulles Intl Airport to Ontario in November is currently the most expensive (average of $661). 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.

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Alternative routes for Dulles Intl 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 Dulles Intl to Ontario

Discover the top 5 airlines that operate flights from Dulles Intl 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 April 19, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$125Average$327FlexibilityNo cancel feeOn-time62%
DeltaCheapest$213Average$437FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$269Average$483FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$278Average$526FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$298Average$572FlexibilityNo cancel feeOn-time71%

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