ONT - LHR

$259 Find Cheap Flights from Ontario to London Heathrow Airport

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Ontario to Heathrow departing on 2/26. 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, 0 bags

KAYAK searches hundreds of travel sites at once for deals on flights to London Heathrow Airport

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Ontario to London.
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Ontario to London.
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Everything you should know

Cheapest round-trip
$579
Typical prices: $677-$988
Iberia
Tue 1/27Thu 2/5
ONT - LHR • 1 stop
Cheapest one-way
$259
Typical prices: $474-$496
Multiple Airlines
Thu 2/26
ONT - LHR • 3 stops
When to travel
November
Cheapest • 26% price drop
September
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
Start a new search
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We hope you love your trip to Heathrow!
Flight Deals
Booking Insights
Flight Deals

Cheap Flights from Ontario to Heathrow (ONT-LHR)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Ontario to Heathrow 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 Ontario to Heathrow

Tue, Jan 27 - Thu, Feb 5
Iberia Logo
10:58 am - 10:00 am
ONT
-
LHR
15h 02m1 stop
Iberia Logo
8:50 pm - 10:48 pm
LHR
-
ONT
33h 58m2 stops
$579Iberia
Wed, Feb 25 - Wed, Mar 4
Iberia Logo
7:00 am - 11:40 am
ONT
-
LHR
20h 40m1 stop
Iberia Logo
7:35 am - 10:49 pm
LHR
-
ONT
23h 14m2 stops
$581Iberia
Wed, Apr 15 - Tue, May 5
British Airways Logo
4:52 pm - 3:05 pm
ONT
-
LHR
14h 13m1 stop
British Airways Logo
6:10 am - 10:35 pm
LHR
-
ONT
24h 25m2 stops
$584British Airways
Tue, Feb 3 - Thu, Feb 19
British Airways Logo
3:09 pm - 12:15 pm
ONT
-
LHR
13h 06m1 stop
British Airways Logo
4:30 pm - 11:59 pm
LHR
-
ONT
15h 29m1 stop
$589British Airways
Tue, Jan 27 - Tue, Feb 3
British Airways Logo
4:45 pm - 1:15 pm
ONT
-
LHR
12h 30m1 stop
British Airways Logo
2:45 pm - 10:48 pm
LHR
-
ONT
16h 03m1 stop
$595British Airways
Wed, Mar 4 - Thu, Mar 12
British Airways Logo
10:56 am - 8:35 am
ONT
-
LHR
13h 39m1 stop
British Airways Logo
9:55 am - 9:24 pm
LHR
-
ONT
18h 29m1 stop
$596British Airways
Mon, Feb 2 - Wed, Feb 18
British Airways Logo
4:45 pm - 1:15 pm
ONT
-
LHR
12h 30m1 stop
British Airways Logo
9:55 am - 7:45 pm
LHR
-
ONT
17h 50m1 stop
$597British Airways
Sun, Jan 25 - Wed, Feb 4
Delta Logo
12:41 pm - 11:40 am
ONT
-
LHR
14h 59m1 stop
Delta Logo
12:30 pm - 9:05 pm
LHR
-
ONT
16h 35m1 stop
$598Delta
Sat, Jan 24 - Thu, Feb 5
British Airways Logo
3:09 pm - 8:35 am
ONT
-
LHR
33h 26m1 stop
British Airways Logo
2:45 pm - 10:48 pm
LHR
-
ONT
16h 03m1 stop
$602British Airways
Wed, Apr 15 - Tue, May 5
British Airways Logo
4:52 pm - 3:05 pm
ONT
-
LHR
14h 13m1 stop
British Airways Logo
8:55 am - 8:54 pm
LHR
-
ONT
19h 59m1 stop
$604British Airways
Booking Insights

KAYAK's insights & trends for Ontario to Heathrow flights

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

How much is a round-trip flight from Ontario to London Heathrow Airport?

This analysis is based on the cheapest round-trip price found on KAYAK in the last 12 months by searching for a flight from Ontario to London Heathrow Airport departing in January.

What is the cheapest month to fly from Ontario to London Heathrow Airport?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Ontario to London Heathrow Airport, 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 Ontario to London Heathrow Airport is November, where tickets cost $624 (return) on average. On the other hand, the most expensive months are June and January, where the average cost of round-trip tickets is $1,331 and $1,052 respectively.

How far in advance should I book a flight from Ontario to London Heathrow Airport?

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Ontario to London Heathrow Airport, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Ontario to London Heathrow Airport, you should book around 1 week before departure. For the absolute cheapest price, our data suggests you should book 15 weeks before departure.

Good to know

Low seasonMarch
Cheapest flight$259
Best time to beat the crowds with an average 14% drop in price.
Most popular time to fly and prices are also 19% lower on average.
Flight from Ontario to London Heathrow Airport

When to book flights from Ontario to Heathrow

Are your dates flexible? Find out the best times to travel from Ontario to Heathrow 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 Ontario to London Heathrow Airport flights

  • What is the cheapest flight from Ontario to London Heathrow Airport?

    In the last 3 days, the lowest price for a flight from Ontario to London Heathrow Airport was $259 for a one-way ticket and $579 for a round-trip.

  • Do I need a passport to fly between Ontario and London Heathrow Airport?

    A passport is required to fly from Ontario to London Heathrow Airport.

  • Which aircraft models fly most regularly from Ontario to London Heathrow Airport?

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

  • Which airline alliances offer flights from Ontario to London Heathrow Airport?

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

  • Which is the best airline for flights from Ontario to London, Delta or KLM?

    The two airlines most popular with KAYAK users for flights from Ontario to London are Delta and KLM. With an average price for the route of $672 and an overall rating of 7.9, Delta is the most popular choice. KLM is also a great choice for the route, with an average price of $653 and an overall rating of 7.7.

  • How does KAYAK find such low prices on flights from Ontario to London Heathrow Airport?

    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 Ontario to London Heathrow Airport.

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to London Heathrow Airport from Ontario 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 Ontario to London Heathrow Airport?

    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 London Heathrow Airport with an airline and back to Ontario with another airline. Booking your flights between Ontario and LHR 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 Ontario to London Heathrow Airport?

    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 London Heathrow Airport from Ontario 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 Ontario to Heathrow

 
See real verified KAYAK customer reviews for airlines flying from Ontario to London. 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 Ontario to Heathrow? 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.
7.9
DeltaOverall score based on 8038 reviews
8.1Boarding
7.9Comfort
8.5Crew
7.2Food
7.8Entertainment
Airline reviews

The flight was delayed for about 2 hrs. Other than it, it was good.

8.0 ExcellentWen, Dec 2025
LAX - MSY
Read more Delta reviews

The flight was delayed for about 2 hrs. Other than it, it was good.

I am extremely disappointed that delta internal pilot manuals now refer to the Gulf of Mexico as the “gulf of America”. You can bow down to the Orange turd on your own. I will never fly delta again

No lunch on a x-country flight scheduled for 10:50 am departure, arrived 5+ hrs later. That requires a black box label before you pay for the tickets. Worst, when I checked in online, it's specifically said that lunch was served on his flight for economy Plus passengers.

Our flight from SFO to MSP was right on time on 11/15/2025. No delays. As we approached MSP at about 8 pm, we circled in the air until 8:40 pm so I don't call that efficient for MSP. I think the captain should announce the delay and why. (as if we all don't know that we are just circling around the area, slowing down, speeding up, slowing down.) Thank you. Marilyn Fischer

Plenty of leg room, temperature was great and staff was excellent. Would do it more often.

Staff were friendly and happy. Delta could make sure passengers that don't have the app know of changes. Without Kayak I would not have known about the change of gate or the delay. Kayak was faster to notify me.

The flight used a B767 with a very old interior from before 2014. The entertainment system did not work at all during the flight despite attempts to reset the system. It was like they flew this route just to be competitive.

Delayed flight (1hour) plus a long layover after an overnight flight with no backup plane available.

Passengers need to check in big baggage instead of bringing on the plane. That cause inconvenience for everyone. Otherwise flight was good.

Flight delayed for two and half hours and then canceled altogether due to mechanical issues. No mechanic onsite to fix so had to send one from LAX.

left on time, reasonable boarding process arrived early luggage came out quickly

Some flight attendants were great others were cranky. Seats were very tight and sitting on an aisle was very hard as the carts and people walking constantly bumped shoulder and arm.

It was great with United overall except for two things. 1) It was a 5-hour flight and we were with kids, so we were asking for extra snacks. They were extremely reticent to dole them out even though there wasn't any meal and the kids were starting to hit their limit towards the end. 2) Baggage didn't arrive until 80 minutes after we landed.

I’m so sorry, I can’t remember her name, I believe it was Dimpti. She was stellar, also a mature Asian flight attendant, lots of flowers in her hair, just as amazing! But literally the crew was AWESOME . Only downside is there weren’t any charging outlets. Maybe I needed to ask a flight attendant , but it would’ve been nice to have one easily accessible.

I boarded flight UA#1318 at Sacramento International Airport going back to Houston TX. The flight was scheduled at 5:10am. I was able to check in virtually using the United Airlines app. When I entered the airport, there was no one outside assisting with checked bags as it was for Delta Airlines. Immediately upon entering, there was a LONG, EXTREMELY LONG line to the kiosks to get boarding passes. I stand in line to get boarding passes then had to move to ANOTHER EXTREMELY LONG line to get my bags checked in. While standing in this line, we noticed an agent taking customers to 3 at a time to her station to check their bags in. Lucky for me, she called me back, checked my bags for me and I was on my way. I then encountered another long line at the TSA check and to avoid I ending up having to sign up for CLEAR to bypass it. So glad, I did.,...Both of my flights were great with no issues, butthe check in progress at Bush Airport was so much smoother. Check-in at SMF airport needs to be anaylzed and corrected. Do better United, I know you can....thanks

Pushed back only to get deplaned due to a tire damaged by ground crew. They did at least go pretty fast. The bathrooms should be banned under the Geneva convention. No room to even sit straight on the toilet. The under-seat entertainment units block what little leg room there is.

United airlines has the best customer experience from booking to arrival. I always fly United airlines. The mileage program is excellent

from SFO-> FRA flight, AVML meal was significantly less compared to regular meal, especially no Desert, no Bread, no sides.

This was an older airplane. The cabin was constantly warm to hot throughout the 10 hour flight and there were no vents to personalize air flow. Also since it was an older plane, the material and comfort of the chairs were very uncomfortable. I left my flight with major soreness on my tailbone.

Older aircraft, no meal, only food was for purchase. Not impressed United.

Disliked having to wait a little longer to disembark from the plan when we landed in London

Food should be better quality. Video screens have poor resolution and the library of movies is poor. The other airlines are much better.

The trip was smooth but the crew were very abrupt, snatching things before finished and being quite snappy when asked questions.

My wife and I love to travel, so we fly a lot. We've already logged 381,075 miles and with practically every major airline. But this flight was very disappointing. It started off well, with no delays and a new plane. But when lunchtime approached, all that good impression was ruined. Instead of white tablecloths, we were offered small, dark placemats, which, as it turned out, were perfectly adequate for the food. All the food offered—and my wife and I only took fish, and the meat—was not just bad, it was downright disgusting and not heated enough. The same applies to the appetizers. This was the first time in many years of traveling that we've been offered such disgusting food.

Lost luggage stuck no clothes and no word after 2 days leaving on cruise no stuff or clothes

Don’t know they cancelled the flight day before I was to leave. They sent a email at 9:00 pm at night saying they cancelled. That is the smooth way to say we don’t want your business! I think they didn’t have enough people booking so they cancelled the flight! It’s all about the money anymore there is no honesty in business.

The flight was canceled 3 hours after original take off time

Pathetic check in experience at JFK. Everything is self check in. Not enough staff present to help with when the check in process or the kiosk gets stuck. Staff present not welcoming or pleasant at all. On the other hand the NY based flight crew was great. Courteous and friendly throughout the flight. Special meals leave a lot to be desired. Kids meals should be made available when kids are flying and same goes for special kids meals too.

Flight was full, and would have preferred an aisle seat, but due to getting a late ticket ,the seat I had was adequate. The flight crew were very help full and hard working. Food and drink were excellent for the 11hr flight. Overall I was pleased with flight, and would recommend British Airways again.

More choices on menu. Seemed only thing offered was Scottish, and while that’s good for the Scot’s it doesn’t help the Americans who don’t like that food. And I really hate it when, during sleep time the attendants have a very loud conversation right over you. Lastly, I paid 5000 dollars for business class, and having to pay more to choose my seat early is really an insult. Seems greedy

The boarding procedure got confusing because they wanted to weigh everyone’s carry-on. Apparently mine was 3 1/2 kg over their limit. I didn’t know they had a limit. And at the check-in desk, nothing was said about this. They wanted me to check the carry-on at no charge and that would have been fine except then they told me at my connection in London I would have to go outside to baggage claim retrieve my bag, and then recheck it. In other words, they could not check it to my final destination, only to London. I told him this was unacceptable so after a few minutes of discussion, they came back and said that my bag would be OK to carry on the plane. It seems that if you have a connection then the weight is not as important. Then when I actually went to board the boarding agent said I needed a tag indicating that my bag had been weighed, even though she had just five minutes ago talked to the same person who cleared me. Lots of confusion seems like a very bad process. They need to improve this.

My flight being automatically moved messed up my travel plans, and I had to quickly find an alternative mode of transportation. I couldn’t get a refund from any of the companies involved. Kayak, Ibiza, or Vueling. I am still unsure of how to settle my concern.

Plane delayed due to weather. Plane boarded, then told to unboard due to a maintenance issue.

the seats were so cramped you could barely move. it was difficult to eat when passengers would recline their seats. the seats were so flimsy and unstable that whenever someone got in and out of their seat, it bounced like a spring back in your face. the movies were nice. the food was terrible. even though the conditions were terrible, they tried to pressure passengers to relocate their seats to accommodate adults who were related and wanted to sit next to each other, even after the passengers expressed that they did not want to move for that purpose. on the connecting flight, the “service” consisted of items for purchase. even though the flight was only 45 minutes, once again passengers (including me) were pressured to relocate for people to sit next to each other. they couldn’t be apart for 45 minutes? this was much less compelling than being apart for an 8 hour flight.

Everything went smoothly, and we even arrived 40min earlier than scheduled, on an Orland-Madrid route.

The staff was very nice and helpful. Some of the best crew I have met.

Suddenly, I don't find my flight back on the app Help Ticket 0757345716866 Hoeflich Flight back Sunday ib5333 Ib2629 Ib4268

Was all good.l including a sofdrink. AA improved significantly. There was no entertainment.

I've taken British Airways before and it has been great. On this trip to Spain and Portugal we had two BA flights. On both flights we were taken by bus from the terminal out to the plane on the tarmac. There were many older folks on these flights, and to ask people in their 70s to lug their carry-on and personal items up the long mobile staircase to the plane entrance, is very disturbing. I won't be taking British Airways in the future. Many people on these flights were very unhappy.

The food on the flight was of marginal quality. Small bits of chicken, instant mashed potatoes and some carrots. The rolls were very dry, nearly inedible. The seats were quite small and didn’t allow for any shifting of position during the flight. There was limited leg room.0

Loved the boarding option from Business class lounge, experience on flight was excellent, plenty of good food choices

The airline was not clear about a new departure time so we got to the airport early anyway. The flight left early which was great because of weather. The check in process was very easy and staff were friendly and helpful. The crew was great and our flight was very good.

Awful it always is unfortunately is the only way to fly direct to london

I travelled in business class and was disappointed by lack of service, curt and borderline rude time of the crew and to top it off, all of my luggage was delayed. It was like pulling teeth to even report the missing luggage and recover it the next day from the airport.

Boarding was poor. All groups called immediately one after the other resulting in a long queue in the jetty/jet bridge. Seats were very hard and and did not recline on a 4.5 hour flight. No food was available. Plane was cold. There was no entertainment.

The cramped seats are cruel and unusual punishment and may violate the Geneva code.

Check in was was and the agent was very friendly and helpful The lounge was nice...boarding was straight from the lounge Everything worked at our seats, and video entertainment was good ..food was mediocre

The flight was excellent in World Travellor plus. Well worth the extra money. Boarding at Phoenix was the usual poorly organized event. Very stressful.

Although business class, the seating was really cramped. The food was so so.

Smooth trip no turbulence which is always a bonus for me lol! In cattle class so an element of being a bit squished (but not as bad as other shorter haul airlines) smaller plane than the one we flew out on and entertainment system wasn’t as modern but still definitely passed the time. Lovely crew x

Everything you need to know for your flight from Ontario to Heathrow

Information on your arrival and departure airports