IAD - ONT

$88 Find Cheap Flights from Washington Dulles Airport to Ontario

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Dulles Intl to Ontario departing on 11/3. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy

KAYAK searches hundreds of travel sites at once for deals on flights to Ontario

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Washington, D.C. to Ontario, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Washington, D.C. to Ontario, as well as popular online travel agencies
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Flight Deals

Cheap Flights from Dulles Intl to Ontario (IAD-ONT)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Dulles Intl to Ontario that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Dulles Intl to Ontario

Thu, Oct 2 - Sun, Oct 5
Frontier Logo
10:17 am - 3:39 pmIAD-ONT
8h 22m1 stop
Frontier Logo
4:09 pm - 9:17 amONT-IAD
14h 08m1 stop
$163Frontier
Find Deal
Sat, Nov 1 - Sat, Nov 8
American Airlines Logo
6:45 am - 11:57 amIAD-ONT
8h 12m1 stop
American Airlines Logo
6:10 am - 4:11 pmONT-IAD
7h 01m1 stop
$186American Airlines
Find Deal
Thu, Oct 2 - Sun, Oct 5
Frontier Logo
10:17 am - 3:39 pmIAD-ONT
8h 22m1 stop
Frontier Logo
7:15 pm - 12:55 pmONT-IAD
14h 40m2 stops
$200Frontier
Find Deal
Tue, Oct 21 - Thu, Oct 23
Multiple Airlines Logo
6:25 am - 12:37 pmIAD-ONT
9h 12m1 stop
Multiple Airlines Logo
4:17 pm - 9:09 amONT-IAD
13h 52m1 stop
$263Multiple Airlines
Find Deal
Thu, Oct 30 - Mon, Nov 3
Delta Logo
6:15 am - 12:16 pmIAD-ONT
9h 01m1 stop
Delta Logo
1:15 pm - 11:33 pmONT-IAD
7h 18m1 stop
$277Delta
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Tue, Oct 14 - Fri, Oct 17
Delta Logo
6:15 am - 12:14 pmIAD-ONT
8h 59m1 stop
Delta Logo
10:00 pm - 1:37 pmONT-IAD
12h 37m2 stops
$282Delta
Find Deal
Sat, Nov 1 - Sat, Nov 8
United Airlines Logo
4:10 pm - 10:51 pmIAD-ONT
9h 41m1 stop
United Airlines Logo
6:38 pm - 5:27 amONT-IAD
7h 49m1 stop
$310United Airlines
Find Deal
Wed, Nov 5 - Sat, Nov 8
United Airlines Logo
4:10 pm - 10:51 pmIAD-ONT
9h 41m1 stop
United Airlines Logo
7:00 am - 5:30 pmONT-IAD
7h 30m1 stop
$313United Airlines
Find Deal
Tue, Oct 21 - Thu, Oct 23
Southwest Logo
7:40 am - 4:40 pmIAD-ONT
12h 00m2 stops
Southwest Logo
2:15 pm - 11:30 pmONT-IAD
6h 15m1 stop
$323Southwest
Find Deal
Sat, Nov 22 - Wed, Nov 26
Southwest Logo
7:45 pm - 9:55 amIAD-ONT
17h 10m2 stops
Southwest Logo
12:20 pm - 11:25 pmONT-IAD
8h 05m1 stop
$358Southwest
Find Deal

Everything you should know

Top airlines
Frontier
Cheapest • from $163 (round-trip)
Southwest
Best reviews • 8.0 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
When to travel
September
Cheapest • 38% price drop
December
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
Cheapest round-trip
$163
Overall average: $472
Frontier
Thu 10/2Sun 10/5
IAD - ONT • 1 stop
Cheapest one-way
$88
Typical prices: $276-372
United Airlines
Mon 11/3
IAD - ONT • 1 stop
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KAYAK searches 100s of sites at once to find you the best travel deals.
We hope you love your trip to Ontario!
Booking Insights

KAYAK's insights & trends for Dulles Intl to Ontario flights

Get data-powered insights and trends into flights from Dulles Intl to Ontario to help you find the cheapest flights, the best time to fly and much more.

What’s the cheapest day of the week to fly from Washington Dulles Airport to Ontario?

The average price of all round-trip flights from Washington, D.C. Dulles Intl Airport to Ontario clicked on KAYAK for each day over the last 12 months.

When flying from Washington Dulles Airport to Ontario, you should consider leaving on a Thursday and avoid Saturdays if you are looking for the best rates. For your return to Washington Dulles Airport, you’ll find the best rates on Thursdays and the most expensive ones on Mondays.

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

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Washington, D.C. Dulles Intl Airport to Ontario, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Washington, D.C. Dulles Intl Airport to Ontario is September, where tickets cost $273 (return) on average. On the other hand, the most expensive months are December and March, where the average cost of round-trip tickets is $639 and $637 respectively.

Good to know

Low seasonFebruary
Cheapest flight$88
Best time to beat the crowds but there is an average 3% increase in price.
Most popular time to fly with an average 44% increase in price.
Flight from Washington Dulles Airport to Ontario

When to book flights from Dulles Intl to Ontario

Are your dates flexible? Find out the best times to travel from Dulles Intl to Ontario based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking Washington Dulles Airport to Ontario flights

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

    In the last 3 days, the lowest price for a flight from Washington, D.C. Dulles Intl Airport to Ontario was $88 for a one-way ticket and $163 for a round-trip.

  • Do I need a passport to fly between Washington Dulles Airport and Ontario?

    No, a passport isn't needed to fly from Washington Dulles Airport to Ontario. However, local authorities might ask for an official ID.

  • Which airports will I be using when flying from Washington Dulles Airport to Ontario?

    Washington Dulles Airport and Ontario are both served by 1 main airport. You will leave Washington Dulles Airport from Washington, D.C. Dulles Intl and will be arriving at Ontario.

  • Which aircraft models fly most regularly from Washington Dulles Airport to Ontario?

    We unfortunately don’t have that data for this specific route.

  • Which airline alliances offer flights from Washington Dulles Airport to Ontario?

    Star Alliance, oneworld, and SkyTeam are the airline alliances operating flights between Washington Dulles Airport and Ontario, with oneworld being the most commonly used for this route.

  • Which is the best airline for flights from Washington, D.C. to Ontario, Southwest or Delta?

    The two airlines most popular with KAYAK users for flights from Washington, D.C. to Ontario are Southwest and Delta. With an average price for the route of $602 and an overall rating of 8.0, Southwest is the most popular choice. Delta is also a great choice for the route, with an average price of $376 and an overall rating of 7.9.

  • How does KAYAK find such low prices on flights from Washington Dulles Airport to Ontario?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Washington Dulles Airport to Ontario.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Washington Dulles Airport to Ontario?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Ontario from Washington Dulles Airport is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Washington Dulles Airport to Ontario?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Ontario with an airline and back to Washington Dulles Airport with another airline. Booking your flights between Washington Dulles Airport and ONT can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Washington Dulles Airport to Ontario?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Ontario from Washington Dulles Airport up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Reviews of the top 5 airlines serving from Dulles Intl to Ontario

 
See real verified KAYAK customer reviews for airlines flying from Washington, D.C. to Ontario. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Dulles Intl to Ontario? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.0
SouthwestOverall score based on 4242 reviews
7.5Entertainment
7.0Food
8.0Comfort
8.6Crew
8.1Boarding
Airline reviews

Very smooth checking in our luggage with a super pleasant SW agent. I enjoyed a fun entertaining movie.

10.0 ExcellentGordon, Jul 2025GEG - OAK
Read more Southwest reviews

Very smooth checking in our luggage with a super pleasant SW agent. I enjoyed a fun entertaining movie.

First time traveling on Southwest since bag fees were implemented. Usual good service. Just more expensive now.

It was a perfect flight in all aspects! Both legs!

Boarding process, crew were good. But the seats were so uncomfortable that was all I could focus on. I literally had to sit forward so that all 3 of us could fit in row. I will try to avoid Southwest in the future for any flights over 60 minutes.

Great flight, 47 passengers on a 180 seat plane. Stewardess was pleasant and cheerful.

Great experience flying Southwest. The crew was really kind and helpful, and very friendly with our toddler.

Plane late from DC to Austin 30 minutes. Crew made up much of the time enroute to San Diego.

Fine, but how to board on SW versus othrr airlines, is just lame. Goood staff though and all was solid otherwise.

Was as expected. Crowed planes. Too many carryons delaying takeoff. But the ride only took an hour and saved me a lot of time SFO is a not a great airport.

I will be flying again Southwest Airlines. Friendly crew, comfortable and affordable.

I was uncomfortably cold on the plane. Other than that it was uneventful and therefore as enjoyable as a plane ride can be.

Food was surprisingly good but the WiFi was not great

My flight was extremely cold. I had a jacket and a cover was left in each seat. The cover was extremely thin and I have a disability, fibromyalgia and arthrithis and AC air is the worst. I closed my vent and my husbands vent and it still was frigid. I asked the attendant if I could get another cover and she quickly almost dismissively and totally unconcerned stating, (I quote) (one per chair) and walked off so quickly that I didn't get a chance to explain to her that I literally have adisability. I didnt want to make a seen so I set on that flight for over 5 hours in pain, joints locking up and extremely uncomfortable. When my fibromyalgia flares up my joints not only ache but they will lock up also and it takes me days to get back to my regular self even though I take medication for it. I felt like it would not have hurt anyone at all for her to just give me an extra cover because I'm sure they have all types of medical issues in people that fly every day.

Not a "Delta" issue, but a JFK issue: We booked a connecting flight with 3 1/2 hours between to clearn immigration and customs. Our inbound flight (BCN to JFK) was on the taxiway 45 minutes which ate into our layover time. Immigtration was insanely quick with the CBP MPC app; however, clearing TSA (again, after we were ALREADY cleared in Spain on the inbound international flight) took over 95 minutes. This left us with 10 minutes before boarding the connecting flight (JFK to SAN) to walk to the far end of Terminal 4 and try to find food. We didn't find any food that could promise to serve us in under 10 minutes so we boarded the Delta flight after coming off a plance and an 8-hour flight knowing that we wouldn't be served any food on the next 5 1/2 hour flight. I feel like Delta needs to put pressure on the JFK TSA to open more screening stations (by our count, we saw only 5 scanners open and a line of - as we said - over 90 minutes. The insult is that we WERE ALREADY SCREENED through TSA, but as you come off one flight into the USA, you have to go through the whole process again. It seems like if you have a connecting flight, there should be a way to pass through immigration and customs without needing to return through TSA.

There are 4 flights in consecutive gates with about the same departure time. Two flights were boarding at the same time. One was delayed or boarding would be happening at the same time. I am not sure what Delta and LAX need to do to have a better layout at the end of Terminal 2

5 hours of delay that could've been much shorter if Delta had taken the 1 hour delay they imposed on the flight before boarding to run any of the plane checks required for flight to find the hydraulic issue that required nearly 3 hours to fix. $24 of meal credit buys a sandwich and a soft drink. Poor communication within the terminal about what gate we'd be re-boarding from and when we'd be re-boarding.

The entertainment and wifi mostly didn't work on this flight.

Terrible entertainment system - kept freezing and audio kept cutting out. Snacks were mediocre at best for a 5 hour flight.

I am still upset that my bag was lost on a recent trip to Rome ; we were inconvenienced and out €150 Euros ; delta has refused to reimburse us

This had nothing to do with Delta… The flights were on time and flawless. The service was excellent. We purchased seats in (aisle/middle) comfort plus since this was a cross country flight. Unfortunately, the woman seated at the window was 300+ pounds and, as might be expected, covered up about a third of the middle seat also. there was absolutely nothing that Delta could have done about that… I just don’t know what the answer should be. If you purchase a seat, you should should be able to use the entire seat and not just the portion that someone else is not sitting/oozing in. Disappointing…there should be something that could be done….I'm just not sure what solution could be.

Great service on board. Boarding a bit slow due to process. Food was pretty average.

Very small cramped plane for an international flight. Everything else was good, but it was maybe the smallest comfort-wise I've ever been on for longer than 3-4 hours and the trip was 7.5

Flight was delayed 3 hours. No food and drink vouchers was provided. They offered a mini pretzel bag and water .

Staff was rude. Didn’t give water for 2 hours. Worst service

Was on time until within 1 hour of flight-how does that happen? Staff very friendly.

I liked the choice of lemon ginger tea. I think stewardesses can be more considerate of older people needs.

We were given vouchers we couldn’t use with a 5.5 hour delay

I fly UAL 7-8 times per year. This flight was not up to snuff because it boarded very late "due to unexpected delays in restocking the plane" and yet Flight Aware showed the plane had landed some 10 hours earlier--so I think they could have planned accordingly. The FA's were nice but harried. The video system had to be rebooted 3-4 times. The food service was rather abrupt; they forgot my row and when I asked for my meal, they brought it with some impatience. Overall, the flight was fine, but the little details made it feel somewhat mundane and hurried.

I didn’t get on plane. Passport being processed by consulate with visa application. Tried to cancel through underpricer after purchasing cacelling for any reason. No dice, they are thieves.

When I booked it on Kayak it aaid that I wasn't allowed hamd luggage. I called United Airlines and it took them 6 minutes to figure out if I was allowed free hand luggage. Surely something that simple they should be able to tell me instantly.

Great. Quick and quiet and east. The breakfast choices were a welcome surprise!

The stewardess hit me with the food kart twice on the head and didn't say I'm sorry once. The same stewardess gave me a warm Apple Juice with No ice. The Flight was delayed for Departure 6 times, starting from 2:36pm, finally taking off 7:50pm. I was late picking up my child from the sitter by 3 hours.

It took way too long to diagnose and solve the problem of a broken crew member cabin seat. Though compensation for the volunteer who left the flight was very kind.

We fly American Airlines quite a bit. And we always fly business class when traveling internationally. We were a bit disappointed with the comfort of this particular plane as well as the entertainment options.

Did not get the seat I selected and paid for.

My flight was delayed for several hours. Sitting at gate 16 for several hours, I got a text from Kayak the gate changed to 9 before it was announced. Very bad communication at each gate from American Airlines employees. I received 10 notifications of delay from Kayak. My vacation started off horrible! I will write to American Airlines corporate office also.

The AA staff person who checked our bags was curt and almost rude. The FA also seemed unhappy doing her job. Overall it was like riding the school bus back in grade school.

Delayed flight that lead to a missed connection and a 5-hour trip became a 12-hour flight 🙄

There is no room, no gluten free options, or any free internet/entertainment. You have to bring your own tablet or smartphone because there are no screens.

Amazing food, great staff, with one noticable detail missing ...but no seat entertainment in any of aircraft ...I am not a fan

Seats were new and comfortable. Staff was fine. Missed my connection due to weather -which wasn’t their fault- but got no help at all. Gate staff sent me to customer service, which was and stayed unstaffed. Sign with QR code directed me to call or chat. Chat was useless. Call was returned after an hour. No itinerary offered by Frontier could get me home in less than 30 hours. Rebooked with another airline and got a partial refund that came to about 10 percent of what I paid to get home.

Finally a Frontier on time and efficient. I've had problems before with your airline, but this time everything went fine.

The experience was good. No frills but I got there safe and sound and on time.

Great for the price. No wifi or entertainment, but gate agents and crew were fantastic and we boarded quickly and left on time.

sluggish boarding and arrival procedures, fake nice flight attendants, and lots of delays.

Disaster. They lied every step of the way. We ended up being delayed due to crew and then allegedly abandoned the flight because of a curfew at LGA. No rebooking to LGA at any reasonable time. No hotel. No meal vouchers. Had to sleep in the airport and fly to Newark instead. Will never fly Frontier again.

What I expected, nickeled and dined and a frontier flight attendant loudly complained about her job and lack of communication as she headed to the gate on her cell phone. Not professional.

As every law enforcement agency I could imagine surrounded the plane and we didn’t disembark for 2 hours and then had to stick around for another hour to go get our personal belongings after leaving them behind and being bused away from the plane, it was scary and inconvenient. We were given no information as to why this was happening. Lack of communication with passengers was disappointing.

After boarding and un-boarding twice over 6+hours, the flight was canceled.

Severe turbulence. Captain never came on to reassure passengers after things settled down.

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