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$110+ 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 9/1. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — ONT
Aug 18 — Aug 251
Tue 8/18
Tue 8/25
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 July 19, 2026.

This Trip.com deal was found by Cheapflights users on 7/14. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/129:50 am
IAD
-
ONT
1 stop8h 24m
Frontier
Wed 8/193:40 pm
ONT
-
IAD
1 stop13h 24m
Frontier
Deal found 7/14$323
This Trip.com deal was found by Cheapflights users on 7/14. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/129:50 am
IAD
-
ONT
1 stop8h 24m
Frontier
Thu 8/208:17 am
ONT
-
IAD
1 stop7h 12m
Frontier
Deal found 7/14$324
This Trip.com deal was found by Cheapflights users on 7/17. 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.
Wed 8/198:59 am
IAD
-
ONT
1 stop9h 55m
Frontier
Mon 8/248:17 am
ONT
-
IAD
1 stop7h 12m
Frontier
Deal found 7/17$329
This Frontier deal was found by Cheapflights users on 7/14. 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.
Wed 8/129:50 am
IAD
-
ONT
1 stop8h 24m
Frontier
Tue 8/183:40 pm
ONT
-
IAD
1 stop13h 24m
Frontier
Deal found 7/14$330
This Kiwi.com deal was found by Cheapflights users on 7/18. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/86:49 am
IAD
-
ONT
2 stops11h 25m
Frontier
Mon 8/1011:47 am
ONT
-
IAD
1 stop17h 33m
Frontier
Deal found 7/18$332
This Trip.com deal was found by Cheapflights users on 7/18. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/189:13 am
IAD
-
ONT
1 stop9h 41m
Frontier
Tue 8/253:40 pm
ONT
-
IAD
1 stop13h 24m
Frontier
Deal found 7/18$335
This Trip.com deal was found by Cheapflights users on 7/14. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/139:50 am
IAD
-
ONT
1 stop9h 04m
Frontier
Thu 8/208:17 am
ONT
-
IAD
1 stop7h 12m
Frontier
Deal found 7/14$338
This Trip.com deal was found by Cheapflights users on 7/14. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/89:30 am
IAD
-
ONT
1 stop8h 44m
Frontier
Sat 8/158:17 am
ONT
-
IAD
1 stop9h 55m
Frontier
Deal found 7/14$340
This Alaska Airlines deal was found by Cheapflights users on 7/14. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/227:00 am
IAD
-
ONT
1 stop9h 21m
Alaska Airlines
Sat 10/2411:13 am
ONT
-
IAD
1 stop9h 46m
Alaska Airlines
Deal found 7/14$341
This Delta deal was found by Cheapflights users on 7/17. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/203:03 pm
IAD
-
ONT
1 stop9h 49m
Delta
Sat 8/2912:00 pm
ONT
-
IAD
1 stop9h 34m
Delta
Deal found 7/17$342
This Trip.com deal was found by Cheapflights users on 7/17. 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.
Tue 8/119:50 am
IAD
-
ONT
1 stop8h 24m
Frontier
Sat 8/158:17 am
ONT
-
IAD
1 stop9h 55m
Frontier
Deal found 7/17$343
This Trip.com deal was found by Cheapflights users on 7/14. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/129:50 am
IAD
-
ONT
1 stop8h 24m
Frontier
Thu 8/1311:47 am
ONT
-
IAD
1 stop17h 33m
Frontier
Deal found 7/14$344

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 July 19, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$323
(Trip.com)

One-way from

$110
(Kiwi.com)

Popular in

April

Cheapest in

September

Average price

$379
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. 30% potential increase in price ($202 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 10% potential price decrease ($43 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in July 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 July 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
Quickest round-trip

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 11/5

6:00 am-11:08 am

1 stop8h 08m

Ontario

Thu 11/12

10:59 pm-9:11 am

1 stop7h 12m

$391

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 9/3

3:40 pm-10:35 pm

1 stop9h 55m

Ontario

Sat 9/12

7:00 am-5:37 pm

1 stop7h 37m

$451

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Fri 10/16

9:35 am-6:03 pm

1 stop11h 28m

Ontario

Sun 10/18

11:13 am-11:59 pm

1 stop9h 46m

$461

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Sun 9/6

6:42 am-12:12 pm

1 stop8h 30m

Ontario

Sat 9/12

7:00 am-5:37 pm

1 stop7h 37m

$462

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Fri 11/6

4:10 pm-10:53 pm

1 stop9h 43m

Ontario

Sat 11/14

6:36 pm-6:00 am

1 stop8h 24m

$466

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Sun 10/18

9:35 am-11:45 pm

1 stop17h 10m

Ontario

Sat 10/24

11:13 am-11:59 pm

1 stop9h 46m

$472

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Sun 12/13

6:30 am-12:20 pm

1 stop8h 50m

Ontario

Thu 12/31

11:59 pm-9:48 am

1 stop6h 49m

$476

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Fri 10/2

4:02 pm-10:49 pm

1 stop9h 47m

Ontario

Sun 10/4

6:00 am-7:02 pm

1 stop10h 02m

$491

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 12/24

7:00 am-2:47 pm

1 stop10h 47m

Ontario

Tue 1/5

4:00 pm-5:38 am

1 stop10h 38m

$526

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 12/24

3:37 pm-10:39 pm

1 stop10h 02m

Ontario

Mon 1/4

11:59 pm-11:43 am

1 stop8h 44m

$530

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/15

Showing 1-10 of 23 resultsSorted by cheapest first
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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 July.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice 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. 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 April is currently the most expensive (average of $917). 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 July 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
4,242 reviews

Crew

8.6

Boarding

8.1

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Reviews

1 / 20
10.0
Excellent

Walter,May 2026

LAS - BUR

Short but excellent flight. Everyone was friendly and professional it was a great flight!
Southwest
8.0
Very good
4,242 reviews
Southwest
8.0
Very good
4,242 reviews

Crew

8.6

Boarding

8.1

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Reviews

1 / 20
10.0
Excellent

Walter,May 2026

LAS - BUR

Short but excellent flight. Everyone was friendly and professional it was a great flight!
Delta
7.8
Good
8,476 reviews
Southwest
8.0
Very good
4,242 reviews

Crew

8.6

Boarding

8.1

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Reviews

1 / 20
10.0
Excellent

Walter,May 2026

LAS - BUR

Short but excellent flight. Everyone was friendly and professional it was a great flight!
United Airlines
7.4
Good
10,007 reviews
Southwest
8.0
Very good
4,242 reviews

Crew

8.6

Boarding

8.1

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Reviews

1 / 20
10.0
Excellent

Walter,May 2026

LAS - BUR

Short but excellent flight. Everyone was friendly and professional it was a great flight!
American Airlines
7.1
Good
11,820 reviews
Southwest
8.0
Very good
4,242 reviews

Crew

8.6

Boarding

8.1

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Reviews

1 / 20
10.0
Excellent

Walter,May 2026

LAS - BUR

Short but excellent flight. Everyone was friendly and professional it was a great flight!
Frontier
5.6
Fair
2,785 reviews
Southwest
8.0
Very good
4,242 reviews

Crew

8.6

Boarding

8.1

Food

7.0

Overall

8.0

Comfort

8.0

Entertainment

7.5

Reviews

1 / 20
10.0
Excellent

Walter,May 2026

LAS - BUR

Short but excellent flight. Everyone was friendly and professional it was a great flight!

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 $391, Delta can have you in Ontario from Washington, D.C. Dulles Intl Airport in 8h 08m. 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 72% 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 $92. However, be on the lookout for offers from Delta and United Airlines, 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 April is currently the most expensive (average of $917). 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 July 19, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$125Average$335FlexibilityNo cancel feeOn-time62%
DeltaCheapest$213Average$397FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$269Average$524FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$278Average$417FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$340Average$445FlexibilityNo cancel feeOn-time71%

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