HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Ontario

$126+ 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 1/10. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — ONT
Nov 28 — Dec 51
Fri 11/28
Fri 12/5
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Dulles Intl to Ontario with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheap 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 October 29, 2025.

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$314
(United Airlines)

One-way from

$126
(Kiwi.com)

Popular in

December

Cheapest in

September

Average price

$398
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. 22% potential increase in price ($128 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease ($18 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in October 2025
Search Deals

Find 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 October 29, 2025.

This United Airlines deal was found by Cheapflights users on 10/27. 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.
Tue 11/184:10 pmIAD - ONT
1 stop9h 41mUnited Airlines
Thu 11/277:00 amONT - IAD
1 stop8h 27mUnited Airlines
Deal found 10/27$314
This Delta deal was found by Cheapflights users on 10/28. 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.
Tue 11/186:00 amIAD - ONT
1 stop8h 06mDelta
Thu 11/201:20 pmONT - IAD
1 stop7h 38mDelta
Deal found 10/28$319
This Delta deal was found by Cheapflights users on 10/27. 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.
Mon 11/175:59 pmIAD - ONT
1 stop8h 05mDelta
Thu 11/276:00 amONT - IAD
2 stops9h 26mDelta
Deal found 10/27$324
This Southwest deal was found by Cheapflights users on 10/28. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/114:40 pmIAD - ONT
1 stop7h 15mSouthwest
Mon 12/1511:15 amONT - IAD
1 stop7h 45mSouthwest
Deal found 10/28$325
This United Airlines deal was found by Cheapflights users on 10/27. 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.
Wed 11/194:10 pmIAD - ONT
1 stop9h 41mUnited Airlines
Thu 11/277:00 amONT - IAD
1 stop8h 27mUnited Airlines
Deal found 10/27$328
This Delta deal was found by Cheapflights users on 10/27. 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 11/186:00 amIAD - ONT
2 stops14h 09mDelta
Thu 11/276:00 amONT - IAD
2 stops9h 26mDelta
Deal found 10/27$329
This Delta deal was found by Cheapflights users on 10/27. 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.
Mon 11/175:59 pmIAD - ONT
1 stop8h 05mDelta
Thu 11/201:20 pmONT - IAD
1 stop7h 38mDelta
Deal found 10/27$339
This Delta deal was found by Cheapflights users on 10/27. 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 12/95:59 pmIAD - ONT
1 stop8h 05mDelta
Sat 12/137:05 amONT - IAD
1 stop6h 55mDelta
Deal found 10/27$347
This Delta deal was found by Cheapflights users on 10/28. 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.
Wed 12/36:00 amIAD - ONT
1 stop8h 02mDelta
Wed 12/34:49 pmONT - IAD
2 stops13h 22mDelta
Deal found 10/28$352
This Kiwi.com deal was found by Cheapflights users on 10/29. 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 11/188:40 amIAD - ONT
2 stops15h 47mFrontier
Tue 11/258:05 amONT - IAD
1 stop23h 30mFrontier
Deal found 10/29$358
This KAYAK deal was found by Cheapflights users on 10/28. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/187:43 amIAD - ONT
1 stop10h 34mAlaska Airlines
Wed 11/194:11 pmONT - IAD
1 stop11h 12mAlaska Airlines
Deal found 10/28$361
This United Airlines deal was found by Cheapflights users on 10/28. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/184:10 pmIAD - ONT
1 stop9h 41mUnited Airlines
Thu 11/201:29 pmONT - IAD
1 stop6h 46mUnited Airlines
Deal found 10/28$363

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 October 29, 2025.
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

Tue 11/18

6:00 am-11:06 am

1 stop8h 06m

Ontario

Thu 11/20

1:20 pm-11:58 pm

1 stop7h 38m

$319

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Sat 1/10

6:20 am-11:54 am

1 stop8h 34m

Ontario

Tue 1/13

1:04 pm-11:37 pm

1 stop7h 33m

$347

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 11/18

8:40 am-9:27 pm

2 stops15h 47m

Ontario

Tue 11/25

8:05 am-10:35 am

1 stop23h 30m

$358

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 11/18

6:00 am-11:06 am

1 stop8h 06m

Ontario

Fri 11/21

1:20 pm-11:58 pm

1 stop7h 38m

$368

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 11/18

7:10 am-12:18 pm

1 stop8h 08m

Ontario

Mon 12/8

4:49 pm-9:11 am

2 stops13h 22m

$373

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Wed 11/26

4:10 pm-10:51 pm

1 stop9h 41m

Ontario

Wed 12/3

1:34 pm-11:15 pm

1 stop6h 41m

$377

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 11/18

7:40 am-6:30 pm

2 stops13h 50m

Ontario

Thu 11/20

5:45 am-3:45 pm

1 stop7h 00m

$379

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 12/4

4:10 pm-10:49 pm

1 stop9h 39m

Ontario

Tue 12/9

5:05 am-3:01 pm

1 stop6h 56m

$382

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 2/24

7:15 am-12:34 pm

1 stop8h 19m

Ontario

Thu 2/26

10:30 pm-9:11 am

1 stop7h 41m

$382

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Sat 2/14

6:00 am-11:38 am

1 stop8h 38m

Ontario

Sat 2/14

10:30 pm-9:11 am

1 stop7h 41m

$383

Flights are sorted by cheapest round-trip flights first.

Deals found on 10/28

Showing 1-10 of 21 results
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 October.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy2 starsTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*1 star
eDreamsPrice 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 eDreams to be most consistent on Cheapflights vs. eDreams Users can find the same prices on Washington, D.C. Dulles Intl Airport-Ontario flight deals on Cheapflights vs. eDreams >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 eDreams the most. eDreams 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, August is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to Ontario (average of $109). Flying from Washington, D.C. Dulles Intl Airport to Ontario in March is currently the most expensive (average of $227). 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 IAD to ONT?

Find hourly flight availability from Dulles Intl 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 October 29, 2025.

It’s typically best to fly out from Washington, D.C. Dulles Intl Airport to Ontario in the morning. Doing so could potentially save you 29% on the flight price compared to flying at noon, which is usually more expensive.

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 October 29, 2025.
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
4,241 reviews

Crew

8.6

Overall

8.0

Comfort

8.0

Food

7.0

Boarding

8.1

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
4,241 reviews
Southwest
8.0
Very good
4,241 reviews

Crew

8.6

Overall

8.0

Comfort

8.0

Food

7.0

Boarding

8.1

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
7.9
Good
7,992 reviews
Southwest
8.0
Very good
4,241 reviews

Crew

8.6

Overall

8.0

Comfort

8.0

Food

7.0

Boarding

8.1

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
8,999 reviews
Southwest
8.0
Very good
4,241 reviews

Crew

8.6

Overall

8.0

Comfort

8.0

Food

7.0

Boarding

8.1

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
11,032 reviews
Southwest
8.0
Very good
4,241 reviews

Crew

8.6

Overall

8.0

Comfort

8.0

Food

7.0

Boarding

8.1

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
3,124 reviews
Southwest
8.0
Very good
4,241 reviews

Crew

8.6

Overall

8.0

Comfort

8.0

Food

7.0

Boarding

8.1

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 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 $319, Delta can have you in Ontario from Washington, D.C. Dulles Intl Airport in 8h 06m. 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 $173 on this airline. Additional options worth looking into are Delta and United Airlines, starting at $213 and $284 round-trip. Frontier is priced at 60% lower than the current average price of a flight leaving 3 months from now.

  • 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 $109). Flying from Washington, D.C. Dulles Intl Airport to Ontario in March is currently the most expensive (average of $227). 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

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Dulles Intl to Ontario

See prices for flight routes from nearby airports that may be better suited for you.
Dulles Intl to Las Vegas flights
Reagan-National to Los Angeles flights
Dulles Intl to Los Angeles flights
Baltimore to Las Vegas flights
Reagan-National to Las Vegas flights
Baltimore to Los Angeles flights
Reagan-National to San Francisco flights
Dulles Intl to San Francisco flights
Baltimore to San Francisco flights
Dulles Intl to San Diego flights
Baltimore to San Diego flights
Reagan-National to San Diego flights
Baltimore to Ontario flights
Reagan-National to Ontario flights
Dulles Intl to San Jose flights
Dulles Intl to Santa Ana flights
Reagan-National to Santa Ana flights
Baltimore to Burbank flights
Baltimore to Santa Ana flights
Baltimore to San Jose flights
Reagan-National to San Jose flights
Dulles Intl to Sacramento flights
Baltimore to Oakland flights
Baltimore to Sacramento flights
Reagan-National to Oakland flights
Dulles Intl to Oakland flights
Dulles Intl to Reno flights
Baltimore to Palm Springs flights
Dulles Intl to Palm Springs flights
Reagan-National to Reno flights
Reagan-National to Sacramento flights
Baltimore to Reno flights
Reagan-National to Palm Springs flights
Reagan-National to Burbank flights
Dulles Intl to Burbank flights
Baltimore to Monterey flights
Dulles Intl to Long Beach flights
Dulles Intl to Monterey flights
Dulles Intl to San Luis Obispo flights
Reagan-National to Santa Barbara flights
Reagan-National to Monterey flights
Dulles Intl to Fresno flights
Baltimore to Long Beach flights
Baltimore to Santa Barbara flights
Dulles Intl to Santa Barbara flights
Baltimore to San Luis Obispo flights
Reagan-National to Fresno flights
Reagan-National to San Luis Obispo flights
Reagan-National to Long Beach flights

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 October 29, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$173Average$328FlexibilityNo cancel feeOn-time62%
DeltaCheapest$213Average$371FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$284Average$510FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$298Average$412FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$304Average$594FlexibilityNo cancel feeOn-time63%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.