ONT - LHR

$380 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 5/10. 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
$620
Overall average: $702
Virgin Atlantic
Sat 2/14Sat 2/21
ONT - LHR • 1 stop
Cheapest one-way
$380
Typical prices: $614-$791
JetBlue
Sun 5/10
ONT - LHR • 1 stop
Top airlines
Virgin Atlantic
Cheapest • from $620 (round-trip)
Delta
Best reviews • 7.9 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
When to travel
November
Cheapest • 25% price drop
September
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
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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

Sat, Feb 14 - Sat, Feb 21
Virgin Atlantic Logo
6:00 am - 10:00 am
ONT
-
LHR
20h 00m1 stop
Virgin Atlantic Logo
12:20 pm - 10:37 pm
LHR
-
ONT
18h 17m1 stop
$620Virgin Atlantic
Sat, Feb 14 - Sat, Feb 21
Multiple Airlines Logo
5:00 am - 7:10 am
ONT
-
LHR
18h 10m2 stops
Multiple Airlines Logo
7:40 am - 9:59 pm
LHR
-
ONT
22h 19m2 stops
$624Multiple Airlines
Mon, Feb 16 - Mon, Feb 23
Multiple Airlines Logo
5:00 am - 7:10 am
ONT
-
LHR
18h 10m2 stops
Multiple Airlines Logo
7:40 am - 10:00 pm
LHR
-
ONT
22h 20m2 stops
$625Multiple Airlines
Sun, Feb 22 - Sun, Mar 8
Iberia Logo
6:10 am - 6:50 am
ONT
-
LHR
16h 40m1 stop
Iberia Logo
6:05 am - 9:30 pm
LHR
-
ONT
23h 25m2 stops
$628Iberia
Tue, Feb 10 - Tue, Feb 24
Iberia Logo
6:00 am - 11:40 am
ONT
-
LHR
21h 40m1 stop
Iberia Logo
6:00 am - 10:49 pm
LHR
-
ONT
24h 49m2 stops
$629Iberia
Wed, Jan 28 - Wed, Feb 4
United Airlines Logo
1:24 pm - 9:40 am
ONT
-
LHR
12h 16m1 stop
United Airlines Logo
11:10 am - 10:53 pm
LHR
-
ONT
19h 43m2 stops
$630United Airlines
Thu, Mar 5 - Thu, Mar 12
KLM Logo
1:15 pm - 11:40 am
ONT
-
LHR
14h 25m1 stop
KLM Logo
6:30 am - 5:12 pm
LHR
-
ONT
17h 42m2 stops
$631KLM
Wed, Jan 28 - Wed, Feb 4
Delta Logo
6:00 am - 9:20 am
ONT
-
LHR
19h 20m2 stops
Delta Logo
6:30 am - 9:05 pm
LHR
-
ONT
22h 35m2 stops
$635Delta
Thu, Jan 29 - Thu, Feb 5
Delta Logo
6:00 am - 6:25 am
ONT
-
LHR
16h 25m2 stops
Delta Logo
8:40 am - 9:05 pm
LHR
-
ONT
20h 25m2 stops
$636Delta
Thu, Jan 29 - Sun, Feb 22
British Airways Logo
4:45 pm - 1:15 pm
ONT
-
LHR
12h 30m1 stop
British Airways Logo
10:35 am - 6:42 pm
LHR
-
ONT
16h 07m1 stop
$639British 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.

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 July, where the average cost of round-trip tickets is $1,317 and $1,009 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 seasonNovember
Cheapest flight$380
Best time to beat the crowds with an average 25% drop in price.
Most popular time to fly and prices are also 17% 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 $380 for a one-way ticket and $620 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 $672 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 8023 reviews
7.9Comfort
7.2Food
8.5Crew
8.1Boarding
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.

Flight was on time, staff are friendly and helpful onboard.

Delay and had to run between flight to get my connection due to this delay but besides that the overall experience was ok. I arrived with just an hour of delay.

They forgot to serve food and the crew was very unfriendly. Never experienced such a bad KLM flight. Usually fly from Toronto. New York was different.

Over 1 Hr delay. No APU so no AC on ground. Plane was hot during boarding and then they closed the doors over 20 minutes before engine start so interior of plane was steamy hot and stuffy. Could have been helped by opening doors until ready to depart.

First of all we couldn’t check in online, then we learn at the airport we were on stand by for KLM’s mistake of overbooking. The seats were not comfy at all. Our luggage got lost.

Ad experience - been flying many years with them but they are losing out to other carriers with their service and bagage / seating policy. My 2 12-yo kids were not placed with the parent. Absurdity.

KLM remains a quality flag carrier airline which maintains its standards whilst all their competitors are lowering theirs.

Our first flight was delayed so we missed our connecting flight. However it was easy to book a later flight on their app.

My flight was delayed by 6 hours then I missed BOTH of my connecting flights, I then had to stay in the AIRPORT at JFK because soooooo many people also suffered from missing flights and there was no hotels available. I would like to be compensated for this experience! I had to stay in the airport for over 16 hours!

The service was great. However the lounge only gets passing grade

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.

Not pleasant trip cross country when the entertainment and WiFi system not working. No entertainment for entirety of route. Staff was rather nonchalant in that they dismissed the problem due to age of plane. It would have been nice to know this up front so I could have come prepared to read or download movies before boarding Coincidentally or not, there was a similar issue with the entertainment system on my previous flight I took on my fist leg of the trip. There are no seat TVs, so you must rely on the app when it works. United can do better. Also, what use it it to pay for boarding group 2 when half of the passengers are in the same line as you?

My experience on this United Airlines flight was highly uncomfortable, primarily due to two issues: Cabin Temperature: The temperature on the Boeing 737 MAX 8 was unacceptably high, feeling consistently around 80 degrees throughout the flight. This made sleeping impossible and significantly detracted from the experience. Seating Arrangement: Being stuck in a middle seat for a six-and-a-half-hour overnight flight compounded the discomfort. Moving forward, I will always purchase a seat assignment to avoid this situation.

Premium Plus is a really good idea for longer flights

Same as last comment. Food sucks. Quality. Not surprising most people have no clue about nourishment Clearly

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 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

Flying on the Boeing 787 from Seattle to London was everything that I expected. Every thing was great.

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

Information on your arrival and departure airports