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Dulles Intl

$108+ 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 8/21. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — IAD
Aug 3 — Aug 101
Sun 8/3
Sun 8/10
1 adult, Economy
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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

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 July 29, 2025.

Round-trip from

$258
(Frontier)

One-way from

$108
(Trip.com)

Popular in

December

Cheapest in

July

Average price

$307
From Ontario to Washington, D.C. Dulles Intl
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One-way flight from Ontario to Washington, D.C. Dulles Intl
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Highest demand for flights based on searches. 18% potential increase in price ($101 potential increase over avg. RT price).
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Cheapest flight prices on average. 4% potential price decrease ($18 potential savings vs. average RT price).
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Average for round-trip flights in July 2025
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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 July 29, 2025.

This Frontier deal was found by Cheapflights users on 7/27. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/55:15 pmONT - IAD
1 stop10h 19mFrontier
Tue 8/127:30 amIAD - ONT
1 stop11h 50mFrontier
Deal found 7/27$258
This Delta deal was found by Cheapflights users on 7/27. 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.
Sat 9/67:05 amONT - IAD
1 stop8h 44mDelta
Sat 9/132:51 pmIAD - ONT
1 stop7h 24mDelta
Deal found 7/27$279
This ezTravel 易遊網 deal was found by Cheapflights users on 7/28. 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 ezTravel 易遊網 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/47:22 pmONT - IAD
1 stop8h 12mMultiple Airlines
Wed 9/37:00 amIAD - ONT
1 stop10h 12mMultiple Airlines
Deal found 7/28$281
This American Airlines deal was found by Cheapflights users on 7/28. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/2711:59 pmONT - IAD
1 stop8h 02mAmerican Airlines
Wed 9/36:25 amIAD - ONT
2 stops12h 40mAmerican Airlines
Deal found 7/28$283
This Southwest deal was found by Cheapflights users on 7/28. 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.
Mon 9/85:20 amONT - IAD
1 stop7h 25mSouthwest
Sat 9/207:00 amIAD - ONT
1 stop7h 00mSouthwest
Deal found 7/28$299
This Alaska Airlines deal was found by Cheapflights users on 7/28. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/2611:39 amONT - IAD
1 stop9h 41mAlaska Airlines
Wed 9/37:00 amIAD - ONT
1 stop10h 12mAlaska Airlines
Deal found 7/28$302
This Hawaiian Airlines deal was found by Cheapflights users on 7/27. 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 Hawaiian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/1311:39 amONT - IAD
1 stop9h 44mHawaiian Airlines
Tue 9/167:00 amIAD - ONT
1 stop10h 12mHawaiian Airlines
Deal found 7/27$352
This United Airlines deal was found by Cheapflights users on 7/28. 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.
Sat 8/237:00 amONT - IAD
1 stop7h 30mUnited Airlines
Tue 8/2612:35 pmIAD - ONT
1 stop8h 02mUnited Airlines
Deal found 7/28$379

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 July 29, 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

Sat 8/9

5:13 pm-6:34 am

1 stop10h 21m

Washington, D.C. Dulles Intl

Tue 8/12

7:30 am-4:20 pm

1 stop11h 50m

$258

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Sat 9/6

7:05 am-6:49 pm

1 stop8h 44m

Washington, D.C. Dulles Intl

Sat 9/13

2:51 pm-7:15 pm

1 stop7h 24m

$279

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Wed 8/27

11:59 pm-11:01 am

1 stop8h 02m

Washington, D.C. Dulles Intl

Wed 9/3

6:25 am-4:05 pm

2 stops12h 40m

$283

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Mon 9/8

5:20 am-3:45 pm

1 stop7h 25m

Washington, D.C. Dulles Intl

Sat 9/20

7:00 am-11:00 am

1 stop7h 00m

$299

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Tue 8/26

11:39 am-12:20 am

1 stop9h 41m

Washington, D.C. Dulles Intl

Wed 9/3

7:00 am-2:12 pm

1 stop10h 12m

$302

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Sat 9/13

11:39 am-12:23 am

1 stop9h 44m

Washington, D.C. Dulles Intl

Tue 9/16

7:00 am-2:12 pm

1 stop10h 12m

$352

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Sat 8/23

7:00 am-5:30 pm

1 stop7h 30m

Washington, D.C. Dulles Intl

Tue 8/26

12:35 pm-5:37 pm

1 stop8h 02m

$379

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Thu 8/21

5:38 pm-6:30 am

1 stop9h 52m

$108

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Wed 10/29

6:10 am-4:47 pm

1 stop7h 37m

$138

OntarioWashington, D.C.

ONT - IAD

ONTIAD

Ontario

Wed 9/3

11:39 am-12:23 am

1 stop9h 44m

$139

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/28

Showing 1-10 of 14 results
1
2

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 July 25, 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, August is the cheapest month in which you can book a flight from Ontario to Washington, D.C. Dulles Intl Airport (average of $309). Flying from Ontario to Washington, D.C. Dulles Intl Airport in April is currently the most expensive (average of $337). 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 July 29, 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 16% 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 July 29, 2025.
Read reviews from past customers who have flown Alaska Airlines, Southwest, and Delta 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.
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Overall

8.0

Crew

8.5

Entertainment

7.1

Comfort

7.8

Boarding

8.1

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

Food

7.1

Overall

8.0

Crew

8.5

Entertainment

7.1

Comfort

7.8

Boarding

8.1

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
4,238 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Overall

8.0

Crew

8.5

Entertainment

7.1

Comfort

7.8

Boarding

8.1

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
7,975 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Overall

8.0

Crew

8.5

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Hawaiian Airlines
7.8
Good
2,605 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Overall

8.0

Crew

8.5

Entertainment

7.1

Comfort

7.8

Boarding

8.1

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
8,892 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Overall

8.0

Crew

8.5

Entertainment

7.1

Comfort

7.8

Boarding

8.1

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 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.

  • 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 $258. Other airlines that can offer you cheap pricing are Delta, from $279, and American Airlines, from $283. Users have found that Frontier is 41% cheaper than the other options available to this destination.

  • What are the cheapest airlines to fly from Ontario to Washington, D.C. Dulles Intl Airport one-way?

    To fly one-way, consider booking your trip with Frontier, which is currently one of the cheapest options available, starting at $108. American Airlines flights start at $138 while deals on Alaska Airlines start at $139 one-way.

  • 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, August is the cheapest month in which you can book a flight from Ontario to Washington, D.C. Dulles Intl Airport (average of $309). Flying from Ontario to Washington, D.C. Dulles Intl Airport in April is currently the most expensive (average of $337). 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
Woodbridge
Arlington
Alexandria
Tysons
Silver Spring
Fredericksburg
Gaithersburg
Towson
Linthicum Heights
Easton
Fairfax
Manassas
Falls Church
Waldorf
Laurel
Rockville
Oxon Hill
National Harbor
Dundalk
Bowie

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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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San Francisco to Reagan-National flights
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Las Vegas to Baltimore flights
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Oakland to Reagan-National flights
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Burbank to Dulles Intl flights
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Reno to Reagan-National flights
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Fresno to Reagan-National flights
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Long Beach to Baltimore flights
Fresno to Baltimore flights
Palm Springs to Baltimore flights
San Luis Obispo to Reagan-National flights
Palm Springs to Reagan-National flights
Reno to Baltimore flights
Monterey to Dulles Intl flights
San Luis Obispo to Baltimore flights
Santa Barbara to Dulles Intl flights
Santa Barbara to Baltimore flights
Monterey to Baltimore flights
Long Beach to Reagan-National flights
Bakersfield to Dulles Intl flights

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 July 29, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$160Average$295FlexibilityNo cancel feeOn-time62%
DeltaCheapest$286Average$406FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$286Average$397FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$316Average$493FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$326Average$472FlexibilityNo cancel feeOn-time63%

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