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$138+ 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 8/13. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — ONT
Jun 18 — Jun 251
Wed 6/18
Wed 6/25
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 June 13, 2025.

Round-trip from

$234
(Frontier)

One-way from

$138
(Trip.com)

Popular in

March

Cheapest in

September

Average price

$358
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. 4% potential price decrease ($19 potential savings vs. average RT price).
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Average for round-trip flights in June 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 June 13, 2025.

This Frontier deal was found by Cheapflights users on 6/12. 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 8/187:30 amIAD - ONT
1 stop7h 23mFrontier
Thu 8/215:38 pmONT - IAD
1 stop9h 52mFrontier
Deal found 6/12$234
This Alaska Airlines deal was found by Cheapflights users on 6/10. 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.
Tue 9/97:00 amIAD - ONT
1 stop10h 09mAlaska Airlines
Mon 9/157:22 pmONT - IAD
1 stop9h 10mAlaska Airlines
Deal found 6/10$296
This Delta deal was found by Cheapflights users on 6/10. 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 9/106:00 amIAD - ONT
1 stop7h 35mDelta
Mon 9/1510:59 pmONT - IAD
1 stop7h 12mDelta
Deal found 6/10$297
This American Airlines deal was found by Cheapflights users on 6/12. 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.
Thu 8/146:04 pmIAD - ONT
1 stop9h 04mAmerican Airlines
Sun 8/1711:59 pmONT - IAD
2 stops12h 20mAmerican Airlines
Deal found 6/12$303
This United Airlines deal was found by Cheapflights users on 6/11. 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.
Fri 10/34:00 pmIAD - ONT
1 stop9h 42mUnited Airlines
Sun 10/126:37 pmONT - IAD
1 stop7h 45mUnited Airlines
Deal found 6/11$399
This Hawaiian Airlines deal was found by Cheapflights users on 6/12. 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 Hawaiian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/126:30 amIAD - ONT
1 stop9h 56mHawaiian Airlines
Tue 8/196:58 pmONT - IAD
1 stop9h 29mHawaiian Airlines
Deal found 6/12$416

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 June 13, 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

Mon 8/18

7:30 am-11:53 am

1 stop7h 23m

Ontario

Thu 8/21

5:38 pm-6:30 am

1 stop9h 52m

$234

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 9/9

7:00 am-2:09 pm

1 stop10h 09m

Ontario

Mon 9/15

7:22 pm-7:32 am

1 stop9h 10m

$296

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Wed 9/10

6:00 am-10:35 am

1 stop7h 35m

Ontario

Mon 9/15

10:59 pm-9:11 am

1 stop7h 12m

$297

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 8/14

6:04 pm-12:08 am

1 stop9h 04m

Ontario

Sun 8/17

11:59 pm-3:19 pm

2 stops12h 20m

$303

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Fri 8/29

6:35 am-12:13 pm

1 stop8h 38m

Ontario

Mon 9/1

6:50 pm-8:08 am

1 stop10h 18m

$398

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Tue 8/12

6:30 am-1:26 pm

1 stop9h 56m

Ontario

Tue 8/19

6:58 pm-7:27 am

1 stop9h 29m

$416

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Wed 8/13

7:30 am-6:27 pm

1 stop13h 57m

$138

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Thu 9/11

7:00 am-2:09 pm

1 stop10h 09m

$147

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Sat 10/25

6:25 am-12:37 pm

1 stop9h 12m

$149

Washington, D.C.Ontario

IAD - ONT

IADONT

Washington, D.C. Dulles Intl

Sat 9/20

3:00 pm-7:42 pm

1 stop7h 42m

$150

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/11

Showing 1-10 of 13 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 June 13, 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.

Rainfall in Ontario by month

Plan your trip to Ontario by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Ontario ranges from 0.1 - 3.4 inches per month. February is typically the wettest month, when rainfall can reach 3.4 in. June is typically the driest time to visit Ontario when rainfall is around 0.1 in.

Temperature in Ontario by month

Plan your trip to Ontario by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Ontario, use this chart to help with planning. For those seeking warmer temperatures, August is the ideal time of year to visit, when temperatures reach an average of 78.8 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 53.6 F).

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 June 13, 2025.
Read reviews from past customers who have flown Alaska Airlines, Southwest and Delta from Washington, D.C. to Ontario. In addition to providing an overall rating, users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Overall

8.0

Food

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Overall

8.0

Food

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Southwest
8.0
Very good
4,287 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Overall

8.0

Food

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Delta
8.0
Very good
7,950 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Overall

8.0

Food

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Hawaiian Airlines
7.9
Good
2,496 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Overall

8.0

Food

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
United Airlines
7.4
Good
8,791 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Entertainment

7.1

Overall

8.0

Food

7.1

Crew

8.5

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

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.

  • 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 $234 on this airline. Additional options worth looking into are Alaska Airlines and Delta, starting at $296 and $297 round-trip. Frontier is priced at 48% 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 $138. However, be on the lookout for offers from Alaska Airlines and Hawaiian 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 $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.

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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Baltimore to Santa Barbara flights
Dulles Intl to Monterey flights
Reagan-National to Fresno flights
Baltimore to Monterey flights
Reagan-National to Monterey flights
Reagan-National to Long Beach flights
Dulles Intl to Medford 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 June 13, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$198Average$318FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$286Average$377FlexibilityNo cancel feeOn-time71%
DeltaCheapest$286Average$386FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$320Average$514FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$326Average$576FlexibilityNo cancel feeOn-time63%

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