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$103+ 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 4/14. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — ONT
Mar 20 — Mar 271
Fri 3/20
Fri 3/27
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 February 18, 2026.

This Kiwi.com deal was found by Cheapflights users on 2/17. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/146:05 am
IAD
-
ONT
2 stops20h 50m
Frontier
Thu 4/236:15 am
ONT
-
IAD
1 stop8h 57m
Frontier
Deal found 2/17$226
This Delta deal was found by Cheapflights users on 2/17. 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.
Wed 4/157:00 am
IAD
-
ONT
1 stop9h 39m
Delta
Wed 4/227:00 am
ONT
-
IAD
1 stop13h 55m
Delta
Deal found 2/17$283
This Delta deal was found by Cheapflights users on 2/17. 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 4/307:00 am
IAD
-
ONT
1 stop9h 39m
Delta
Tue 5/52:20 pm
ONT
-
IAD
1 stop30h 35m
Delta
Deal found 2/17$303
This Delta deal was found by Cheapflights users on 2/15. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/297:00 am
IAD
-
ONT
1 stop9h 39m
Delta
Tue 5/55:55 pm
ONT
-
IAD
2 stops15h 10m
Delta
Deal found 2/15$308
This Delta deal was found by Cheapflights users on 2/16. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 3/126:01 am
IAD
-
ONT
1 stop8h 46m
Delta
Tue 3/1710:25 pm
ONT
-
IAD
1 stop7h 45m
Delta
Deal found 2/16$319
This Alaska Airlines deal was found by Cheapflights users on 2/17. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/17:10 am
IAD
-
ONT
1 stop19h 49m
Alaska Airlines
Mon 5/43:26 pm
ONT
-
IAD
1 stop29h 43m
Alaska Airlines
Deal found 2/17$323
This Southwest deal was found by Cheapflights users on 2/15. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 3/125:50 am
IAD
-
ONT
1 stop12h 50m
Southwest
Tue 3/171:40 pm
ONT
-
IAD
1 stop7h 00m
Southwest
Deal found 2/15$324
This American Airlines deal was found by Cheapflights users on 2/15. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/187:00 am
IAD
-
ONT
1 stop14h 37m
American Airlines
Mon 4/2711:29 pm
ONT
-
IAD
1 stop7h 33m
American Airlines
Deal found 2/15$326
This Southwest deal was found by Cheapflights users on 2/15. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 3/116:10 pm
IAD
-
ONT
1 stop8h 00m
Southwest
Wed 4/16:25 am
ONT
-
IAD
1 stop6h 30m
Southwest
Deal found 2/15$328
This American Airlines deal was found by Cheapflights users on 2/16. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 3/162:03 pm
IAD
-
ONT
2 stops12h 56m
American Airlines
Mon 3/237:59 pm
ONT
-
IAD
2 stops12h 01m
American Airlines
Deal found 2/16$329
This American Airlines deal was found by Cheapflights users on 2/16. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 3/246:00 am
IAD
-
ONT
1 stop10h 48m
American Airlines
Tue 3/317:59 pm
ONT
-
IAD
2 stops9h 49m
American Airlines
Deal found 2/16$333
This Alaska Airlines deal was found by Cheapflights users on 2/17. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/227:10 am
IAD
-
ONT
1 stop10h 22m
Alaska Airlines
Wed 4/293:26 pm
ONT
-
IAD
1 stop11h 24m
Alaska Airlines
Deal found 2/17$337

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 February 18, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$226
(Kiwi.com)

One-way from

$103
(Kiwi.com)

Popular in

November

Cheapest in

September

Average price

$357
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. 21% potential increase in price ($117 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease ($21 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in February 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 February 18, 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

Dulles Intl

Fly to

Ontario

Route

Depart

Return

Price

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Wed 4/29

7:10 am-9:45 am

1 stop29h 35m

Ontario

Tue 5/5

10:39 am-12:09 am

1 stop10h 30m

$303

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 3/12

6:01 am-11:47 am

1 stop8h 46m

Ontario

Tue 3/17

10:25 pm-9:10 am

1 stop7h 45m

$319

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Wed 5/6

7:10 am-2:30 pm

1 stop10h 20m

Ontario

Mon 5/11

3:26 pm-5:50 am

1 stop11h 24m

$323

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Mon 3/23

7:00 am-9:39 am

1 stop29h 39m

Ontario

Thu 4/2

7:08 pm-6:11 pm

1 stop20h 03m

$323

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Wed 3/11

6:10 pm-11:10 pm

1 stop8h 00m

Ontario

Wed 4/1

6:25 am-3:55 pm

1 stop6h 30m

$328

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 3/17

2:12 pm-8:50 pm

1 stop9h 38m

Ontario

Tue 3/24

6:37 pm-5:36 am

1 stop7h 59m

$337

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Wed 4/1

6:10 pm-11:10 pm

1 stop8h 00m

Ontario

Wed 4/8

6:55 am-4:50 pm

1 stop6h 55m

$337

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 5/12

2:37 pm-8:36 pm

1 stop8h 59m

Ontario

Wed 5/20

1:30 pm-1:24 am

1 stop8h 54m

$337

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Wed 4/22

7:10 am-2:32 pm

1 stop10h 22m

Ontario

Wed 4/29

10:39 am-12:09 am

1 stop10h 30m

$337

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 3/17

2:15 pm-11:51 pm

2 stops12h 36m

Ontario

Tue 3/24

10:25 pm-9:10 am

1 stop7h 45m

$342

Flights are sorted by cheapest round-trip flights first.

Deals found on 2/14

Showing 1-10 of 23 results
1
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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 February.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
PricelinePrice Accuracy1 starTrust Score*3 stars
JustAirTicketPrice Accuracy-Trust Score*1 star

*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

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

Use this chart to determine the optimal time to book a round-trip flight from Dulles Intl to Ontario. Price data was last updated on February 13, 2026.

The best time to book flights from Washington, D.C. Dulles Intl Airport to Ontario is 21 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. Dulles Intl Airport to Ontario?

Currently, August is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to Ontario (average of $111). Flying from Washington, D.C. Dulles Intl Airport to Ontario in December is currently the most expensive (average of $237). 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.

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 February 18, 2026.
Read reviews from past customers who have flown Southwest, Delta, and United 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
4,294 reviews

Food

7.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Crew

8.6

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
8.0
Very good
4,294 reviews
Southwest
8.0
Very good
4,294 reviews

Food

7.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Crew

8.6

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
8,208 reviews
Southwest
8.0
Very good
4,294 reviews

Food

7.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Crew

8.6

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
9,312 reviews
Southwest
8.0
Very good
4,294 reviews

Food

7.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Crew

8.6

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
11,304 reviews
Southwest
8.0
Very good
4,294 reviews

Food

7.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Crew

8.6

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
5.7
Fair
3,048 reviews
Southwest
8.0
Very good
4,294 reviews

Food

7.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Crew

8.6

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 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 $328, Alaska Airlines can have you in Ontario from Washington, D.C. Dulles Intl Airport in 8h. 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 Southwest, starting at $213 and $278 round-trip. Frontier is priced at 70% 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 American Airlines 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, August is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to Ontario (average of $111). Flying from Washington, D.C. Dulles Intl Airport to Ontario in December is currently the most expensive (average of $237). 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 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 February 18, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$125Average$328FlexibilityNo cancel feeOn-time62%
DeltaCheapest$213Average$397FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$278Average$526FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$284Average$475FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$298Average$423FlexibilityNo cancel feeOn-time71%

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