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$81+ 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 9/4. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — ONT
Aug 23 — Aug 301
Sat 8/23
Sat 8/30
1 adult, Economy
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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 August 18, 2025.

Round-trip from

$161
(Mytrip)

One-way from

$81
(Mytrip)

Popular in

March

Cheapest in

June

Average price

$329
From Washington, D.C. Dulles Intl to Ontario
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One-way flight from Washington, D.C. Dulles Intl to Ontario
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Highest demand for flights based on searches. 8% potential increase in price ($41 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease ($17 potential savings vs. average RT price).
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Average for round-trip flights in August 2025
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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 August 18, 2025.

This Mytrip deal was found by Cheapflights users on 8/17. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/410:17 amIAD - ONT
1 stop8h 12mFrontier
Sun 9/77:15 pmONT - IAD
1 stop11h 02mFrontier
Deal found 8/17$161
This Booking.com deal was found by Cheapflights users on 8/18. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/1110:17 amIAD - ONT
1 stop8h 12mFrontier
Sun 9/147:15 pmONT - IAD
1 stop11h 02mFrontier
Deal found 8/18$162
This Booking.com deal was found by Cheapflights users on 8/16. 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.
Thu 9/1810:17 amIAD - ONT
1 stop8h 12mFrontier
Sun 9/217:15 pmONT - IAD
1 stop11h 02mFrontier
Deal found 8/16$163
This Frontier deal was found by Cheapflights users on 8/17. 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.
Mon 8/258:00 amIAD - ONT
1 stop6h 51mFrontier
Thu 9/44:14 pmONT - IAD
1 stop14h 03mFrontier
Deal found 8/17$197
This Frontier deal was found by Cheapflights users on 8/18. 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 9/710:17 amIAD - ONT
1 stop8h 07mFrontier
Thu 9/113:43 pmONT - IAD
2 stops14h 34mFrontier
Deal found 8/18$199
This Frontier deal was found by Cheapflights users on 8/17. 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.
Sat 9/61:02 pmIAD - ONT
2 stops11h 54mFrontier
Sun 9/77:15 pmONT - IAD
1 stop11h 02mFrontier
Deal found 8/17$202
This FlightHub deal was found by Cheapflights users on 8/18. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/258:00 amIAD - ONT
1 stop6h 51mFrontier
Fri 9/512:13 pmONT - IAD
1 stop20h 49mFrontier
Deal found 8/18$204
This Frontier deal was found by Cheapflights users on 8/18. 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.
Mon 9/86:10 amIAD - ONT
2 stops17h 46mFrontier
Thu 9/114:14 pmONT - IAD
1 stop14h 03mFrontier
Deal found 8/18$206
This Mytrip deal was found by Cheapflights users on 8/17. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/258:00 amIAD - ONT
1 stop15h 52mFrontier
Wed 8/278:00 amONT - IAD
1 stop19h 30mFrontier
Deal found 8/17$213
This Mytrip deal was found by Cheapflights users on 8/18. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/258:00 amIAD - ONT
1 stop15h 52mFrontier
Thu 8/286:00 amONT - IAD
1 stop21h 30mFrontier
Deal found 8/18$214
This Mytrip deal was found by Cheapflights users on 8/17. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/288:00 amIAD - ONT
1 stop11h 53mFrontier
Thu 9/44:14 pmONT - IAD
1 stop14h 03mFrontier
Deal found 8/17$215

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 August 18, 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

Thu 9/25

10:17 am-3:29 pm

1 stop8h 12m

Ontario

Sun 9/28

7:15 pm-9:17 am

1 stop11h 02m

$161

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 10/2

10:17 am-3:39 pm

1 stop8h 22m

Ontario

Sun 10/5

7:15 pm-9:17 am

1 stop11h 02m

$161

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 9/4

10:17 am-3:29 pm

1 stop8h 12m

Ontario

Sun 9/7

7:15 pm-9:17 am

1 stop11h 02m

$161

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 9/25

10:17 am-3:29 pm

1 stop8h 12m

Ontario

Thu 10/2

4:34 pm-9:17 am

1 stop13h 43m

$161

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 9/11

10:17 am-3:29 pm

1 stop8h 12m

Ontario

Sun 9/14

7:15 pm-9:17 am

1 stop11h 02m

$162

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 9/18

10:17 am-3:29 pm

1 stop8h 12m

Ontario

Sun 9/21

7:15 pm-9:17 am

1 stop11h 02m

$163

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 8/28

8:00 am-4:53 pm

1 stop11h 53m

Ontario

Sun 9/7

7:15 pm-9:17 am

1 stop11h 02m

$197

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Sun 9/7

10:17 am-3:24 pm

1 stop8h 07m

Ontario

Thu 9/11

3:43 pm-9:17 am

2 stops14h 34m

$199

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 9/4

10:17 am-3:29 pm

1 stop8h 12m

Ontario

Thu 9/18

3:43 pm-12:55 pm

2 stops18h 12m

$199

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 9/11

10:17 am-3:29 pm

1 stop8h 12m

Ontario

Fri 9/12

10:28 pm-12:02 pm

2 stops10h 34m

$202

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/18

Showing 1-10 of 18 results
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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 $246). Flying from Washington, D.C. Dulles Intl Airport to Ontario in March is currently the most expensive (average of $328). 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 August 18, 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 30% 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 August 18, 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
4,246 reviews

Entertainment

7.5

Comfort

8.0

Boarding

8.1

Food

7.0

Crew

8.6

Overall

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
4,246 reviews
Southwest
8.0
Very good
4,246 reviews

Entertainment

7.5

Comfort

8.0

Boarding

8.1

Food

7.0

Crew

8.6

Overall

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
8.0
Very good
7,981 reviews
Southwest
8.0
Very good
4,246 reviews

Entertainment

7.5

Comfort

8.0

Boarding

8.1

Food

7.0

Crew

8.6

Overall

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
8,925 reviews
Southwest
8.0
Very good
4,246 reviews

Entertainment

7.5

Comfort

8.0

Boarding

8.1

Food

7.0

Crew

8.6

Overall

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
10,000 reviews
Southwest
8.0
Very good
4,246 reviews

Entertainment

7.5

Comfort

8.0

Boarding

8.1

Food

7.0

Crew

8.6

Overall

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
5.8
Fair
3,212 reviews
Southwest
8.0
Very good
4,246 reviews

Entertainment

7.5

Comfort

8.0

Boarding

8.1

Food

7.0

Crew

8.6

Overall

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 $161, Frontier can have you in Ontario from Washington, D.C. Dulles Intl Airport in 8h 12m. The distance between Washington, D.C. Dulles Intl Airport and Ontario is about 2236 mi.

  • 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 American Airlines and Delta, starting at $286 and $286 round-trip. Frontier is priced at 61% 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 $246). Flying from Washington, D.C. Dulles Intl Airport to Ontario in March is currently the most expensive (average of $328). 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 August 18, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$173Average$328FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$286Average$376FlexibilityNo cancel feeOn-time71%
DeltaCheapest$286Average$376FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$296Average$573FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$326Average$509FlexibilityNo cancel feeOn-time69%

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