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Dulles Intl

$98+ Cheap flights from Ontario (ONT) to Dulles Intl (IAD)

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 11/19. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — IAD
Nov 15 — Nov 221
Sat 11/15
Sat 11/22
1 adult, Economy
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Find cheap flights from Ontario to Dulles Intl 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

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3. Compare prices and book

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Cheapflights Tip: The best prices from Ontario to Washington, D.C. Dulles Intl are usually found in July or August, booked 15 days in advance, depart on a Thursday or Saturday and return on a Thursday

Find flight deals from Ontario to Dulles Intl

Cheapest flights from Ontario to Dulles Intl
Explore the most affordable flight options available from Ontario to Dulles Intl. Find the lowest fares from popular airlines and budget airlines, with prices last updated on October 16, 2025.

This Trip.com deal was found by Cheapflights users on 10/15. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/86:53 amONT - IAD
2 stops14h 02mFrontier
Tue 11/118:40 amIAD - ONT
2 stops15h 49mFrontier
Deal found 10/15$266
This Trip.com deal was found by Cheapflights users on 10/15. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/66:53 amONT - IAD
2 stops14h 18mFrontier
Sun 11/96:00 amIAD - ONT
2 stops20h 40mFrontier
Deal found 10/15$273
This KAYAK deal was found by Cheapflights users on 10/15. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/84:11 pmONT - IAD
1 stop11h 12mAlaska Airlines
Wed 11/127:43 amIAD - ONT
1 stop10h 34mAlaska Airlines
Deal found 10/15$298
This Delta deal was found by Cheapflights users on 10/16. 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.
Sat 11/151:20 pmONT - IAD
1 stop7h 38mDelta
Sun 11/167:10 amIAD - ONT
1 stop8h 08mDelta
Deal found 10/16$305
This United Airlines deal was found by Cheapflights users on 10/15. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/127:00 amONT - IAD
1 stop7h 30mUnited Airlines
Wed 11/194:10 pmIAD - ONT
1 stop9h 41mUnited Airlines
Deal found 10/15$307
This American Airlines deal was found by Cheapflights users on 10/16. 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.
Wed 11/1910:34 pmONT - IAD
1 stop7h 07mAmerican Airlines
Sun 11/239:12 amIAD - ONT
2 stops12h 08mAmerican Airlines
Deal found 10/16$310
This Delta deal was found by Cheapflights users on 10/16. 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.
Mon 11/1010:25 pmONT - IAD
1 stop7h 45mDelta
Sat 11/157:10 amIAD - ONT
1 stop8h 08mDelta
Deal found 10/16$312
This Delta deal was found by Cheapflights users on 10/15. 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.
Sat 11/85:50 pmONT - IAD
2 stops13h 58mDelta
Mon 11/177:15 amIAD - ONT
1 stop12h 54mDelta
Deal found 10/15$317
This Alaska Airlines deal was found by Cheapflights users on 10/16. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/136:11 pmONT - IAD
1 stop9h 12mAlaska Airlines
Mon 11/177:43 amIAD - ONT
1 stop10h 34mAlaska Airlines
Deal found 10/16$318
This Delta deal was found by Cheapflights users on 10/15. 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.
Sat 11/81:15 pmONT - IAD
1 stop7h 18mDelta
Tue 11/117:10 amIAD - ONT
1 stop8h 08mDelta
Deal found 10/15$319
This lastminute.com deal was found by Cheapflights users on 10/13. 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 lastminute.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/412:13 pmONT - IAD
1 stop14h 53mHawaiian Airlines
Wed 12/107:34 amIAD - ONT
1 stop13h 59mHawaiian Airlines
Deal found 10/13$322

Cheap flight deals from Ontario to Dulles Intl

Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to Dulles Intl (IAD). 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 16, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$266
(Trip.com)

One-way from

$98
(Kiwi.com)

Popular in

December

Cheapest in

July

Average price

$397
Provider with most accurate pricing for Ontario-Washington, D.C. Dulles Intl flight deals.
Search Deals
Provider most trusted by Cheapflights users for Ontario-Washington, D.C. Dulles Intl flights.
Search Deals
From Ontario to Washington, D.C. Dulles Intl
Search Deals
One-way flight from Ontario to Washington, D.C. Dulles Intl
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 ($18 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in October 2025
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Ontario to Dulles Intl 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 16, 2025.
Use the filters below to find and compare flights from Ontario to Washington, D.C. Dulles Intl Airport that are best for you.

Fly from

Ontario

Fly to

Dulles Intl

Route

Depart

Return

Price

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Thu 12/4

6:41 pm-5:27 am

1 stop7h 46m

Washington, D.C. Dulles Intl

Tue 12/9

4:00 pm-8:42 pm

1 stop7h 42m

$305

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Fri 12/12

2:15 pm-11:30 pm

1 stop6h 15m

Washington, D.C. Dulles Intl

Sun 12/14

7:50 pm-12:05 am

1 stop7h 15m

$305

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Fri 2/20

10:30 pm-9:11 am

1 stop7h 41m

Washington, D.C. Dulles Intl

Tue 2/24

12:30 pm-9:14 pm

2 stops11h 44m

$310

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Tue 1/13

1:00 pm-11:17 pm

1 stop7h 17m

Washington, D.C. Dulles Intl

Tue 1/20

3:00 pm-11:52 pm

2 stops11h 52m

$310

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Sat 11/15

4:11 pm-6:23 am

1 stop11h 12m

Washington, D.C. Dulles Intl

Mon 11/17

7:43 am-3:17 pm

1 stop10h 34m

$318

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Fri 10/31

11:36 am-11:18 pm

1 stop8h 42m

Washington, D.C. Dulles Intl

Tue 11/4

6:15 am-12:14 pm

1 stop8h 59m

$319

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Fri 10/31

11:36 am-11:18 pm

1 stop8h 42m

Washington, D.C. Dulles Intl

Wed 11/5

5:52 pm-10:22 pm

1 stop7h 30m

$319

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Sat 2/28

6:00 am-5:55 pm

1 stop8h 55m

Washington, D.C. Dulles Intl

Wed 3/4

7:00 am-6:17 pm

1 stop14h 17m

$346

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Tue 2/17

10:30 pm-9:11 am

1 stop7h 41m

Washington, D.C. Dulles Intl

Thu 2/19

6:00 am-11:38 am

1 stop8h 38m

$359

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Tue 11/4

11:48 am-12:40 am

1 stop9h 52m

Washington, D.C. Dulles Intl

Thu 11/6

5:52 pm-10:22 pm

1 stop7h 30m

$359

Flights are sorted by cheapest round-trip flights first.

Deals found on 10/15

Showing 1-10 of 22 results
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Compare providers for flights from Ontario to Dulles Intl

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 Ontario to Dulles Intl in October.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy2 starsTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
eDreamsPrice 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 Ontario-Washington, D.C. Dulles Intl Airport flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ontario-Washington, D.C. Dulles Intl Airport flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ontario-Washington, D.C. Dulles Intl Airport flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Ontario-Washington, D.C. Dulles Intl Airport 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 Ontario-Washington, D.C. Dulles Intl Airport 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 Ontario to Dulles Intl

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

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

Use this chart to determine the optimal time to book a round-trip flight from Ontario to Dulles Intl. Price data was last updated on October 10, 2025.

The price you pay for your flight from Ontario to Washington, D.C. Dulles Intl Airport may vary depending on when you book. For the best chance of a lower fare, look to book 15 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

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

Currently, June is the cheapest month in which you can book a flight from Ontario to Washington, D.C. Dulles Intl Airport (average of $142). Flying from Ontario to Washington, D.C. Dulles Intl Airport in December is currently the most expensive (average of $235). 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 ONT to IAD?

Find hourly flight availability from Ontario to Dulles Intl. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated October 16, 2025.

A simple way to save on the total cost of your ticket is to fly from Ontario to Washington, D.C. Dulles Intl Airport in the afternoon. If you’re flexible enough to do this you can expect to save up to 15% on your trip compared to booking a flight in the morning.

What is the cheapest day to fly from Ontario to Washington, D.C. Dulles Intl Airport?

Use this chart to determine the cheapest time to fly round-trip from Ontario to Dulles Intl. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their Ontario to Washington, D.C. Dulles Intl Airport flight should consider departing on Monday afternoons when fares are most often at their lowest. Monday mornings flights should be avoided if possible as fares are typically the most expensive at this time.

Reviews of airlines servicing Dulles Intl

Get insights into the airlines that provide service to Dulles Intl. 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 Dulles Intl. Reviews last updated October 16, 2025.
Read reviews from past customers who have flown Southwest, Delta, and United Airlines from Ontario to Washington, D.C. Dulles Intl Airport. 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

Entertainment

7.5

Food

7.0

Boarding

8.1

Overall

8.0

Comfort

8.0

Crew

8.6

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

Entertainment

7.5

Food

7.0

Boarding

8.1

Overall

8.0

Comfort

8.0

Crew

8.6

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
8.0
Very good
7,984 reviews
Southwest
8.0
Very good
4,241 reviews

Entertainment

7.5

Food

7.0

Boarding

8.1

Overall

8.0

Comfort

8.0

Crew

8.6

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
8,982 reviews
Southwest
8.0
Very good
4,241 reviews

Entertainment

7.5

Food

7.0

Boarding

8.1

Overall

8.0

Comfort

8.0

Crew

8.6

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
11,043 reviews
Southwest
8.0
Very good
4,241 reviews

Entertainment

7.5

Food

7.0

Boarding

8.1

Overall

8.0

Comfort

8.0

Crew

8.6

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
3,137 reviews
Southwest
8.0
Very good
4,241 reviews

Entertainment

7.5

Food

7.0

Boarding

8.1

Overall

8.0

Comfort

8.0

Crew

8.6

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 Ontario to Dulles Intl. 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 from for flights from Ontario to Washington, D.C. Dulles Intl?

    Most people fly from Ontario (ONT) if they book a flight from Ontario to Washington, D.C. Dulles Intl. On average, Ontario has 0 outbound flights to Washington, D.C. Dulles Intl per day from 5 airlines. Ontario is conveniently located just 3.1 mi from Ontario’s city center.

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

    Airlines like United Airlines, Southwest, and Delta fly from Ontario to Washington, D.C. Dulles Intl Airport in about 6h 15m. The time it takes to get you to your destination can typically vary by up to 1h 31m. Ontario and Washington, D.C. Dulles Intl Airport are separated by a distance of 2236 mi. This flight may include one or multiple stops.

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

    Cheapflights users have booked flights from Ontario to Washington, D.C. Dulles Intl Airport round-trip from $160. Other airlines that can offer you cheap pricing are American Airlines, from $278, and United Airlines, from $292. Users have found that Frontier is 63% cheaper than the other options available to this destination.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Ontario to Dulles Intl 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 Ontario to Washington, D.C. Dulles Intl Airport?

    Currently, June is the cheapest month in which you can book a flight from Ontario to Washington, D.C. Dulles Intl Airport (average of $142). Flying from Ontario to Washington, D.C. Dulles Intl Airport in December is currently the most expensive (average of $235). 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

Traveling to a place near Washington, D.C. Dulles Intl Airport?

Book flights to Washington, D.C. Dulles Intl Airport if you plan to visit one of these locations
Alexandria
Woodbridge
Arlington
Tysons
Springfield
Silver Spring
Hanover
Gaithersburg
Fredericksburg
Fairfax
Linthicum Heights
Falls Church
Owings Mills
Manassas
Largo
Oxon Hill
Laurel
Towson
National Harbor
Waldorf

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Alternative routes for Ontario to Dulles Intl

See prices for flight routes from nearby airports that may be better suited for you.
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Top 5 airlines flying from Ontario to Dulles Intl

Discover the top 5 airlines that operate flights from Ontario to Dulles Intl. 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 16, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$160Average$295FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$278Average$379FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$292Average$494FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$318Average$468FlexibilityNo cancel feeOn-time63%
DeltaCheapest$318Average$426FlexibilityNo cancel feeOn-timeN/A

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