ONT - LHR

$478 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 8/15. 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, 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 Ontario to London, as well as popular online travel agencies
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Everything you should know

Cheapest round-trip
$891
Typical prices: $931-$678
Iberia
Mon 10/5Tue 10/20
ONT - LHR • 1 stop
Cheapest one-way
$478
Typical prices: $503-$543
Multiple Airlines
Sat 8/15
ONT - LHR • 3 stops
Top airlines
Cheapest • from $891 (round-trip)
Best reviews • 7.9 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
Nonstop flights
Not available
There are currently no direct flights between Ontario and Heathrow. You'll need at least 1 connection.
Insights
Insights
Insights
Insights
Top layover airports
Cheapest • Avg $587 (round-trip)
Shortest trip • 12h 25m (one-way)
Insights
Insights
Insights
Insights
When to travel
Cheapest • 30% price drop
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
Start a new search
KAYAK searches 100s of sites at once to find you the best travel deals.
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

Mon, Oct 5 - Tue, Oct 20
Iberia Logo
10:25 am - 12:50 pm
ONT
-
LHR
18h 25m
1 stop
Iberia Logo
6:15 am - 6:57 pm
LHR
-
ONT
20h 42m
2 stops
$891Iberia
Sun, Aug 23 - Tue, Sep 8
KLM Logo
11:55 am - 3:35 pm
ONT
-
LHR
19h 40m
1 stop
KLM Logo
6:30 am - 4:14 pm
LHR
-
ONT
17h 44m
2 stops
$896KLM
Mon, Aug 3 - Thu, Aug 20
Delta Logo
6:00 am - 11:20 am
ONT
-
LHR
21h 20m
2 stops
Delta Logo
6:30 am - 9:56 pm
LHR
-
ONT
23h 26m
2 stops
$900Delta
Mon, Aug 3 - Thu, Aug 20
Delta Logo
9:40 am - 1:05 pm
ONT
-
LHR
19h 25m
2 stops
Delta Logo
6:30 am - 6:01 pm
LHR
-
ONT
19h 31m
2 stops
$901Delta
Wed, Aug 19 - Wed, Sep 9
Delta Logo
5:55 pm - 3:35 pm
ONT
-
LHR
13h 40m
1 stop
Delta Logo
6:15 am - 4:14 pm
LHR
-
ONT
17h 59m
2 stops
$903Delta
Wed, Aug 19 - Wed, Sep 9
United Airlines Logo
1:18 pm - 9:40 am
ONT
-
LHR
12h 22m
1 stop
United Airlines Logo
7:30 am - 6:11 pm
LHR
-
ONT
18h 41m
2 stops
$907United Airlines
Mon, Aug 17 - Wed, Sep 2
United Airlines Logo
5:45 am - 7:45 am
ONT
-
LHR
18h 00m
1 stop
United Airlines Logo
9:30 am - 9:59 pm
LHR
-
ONT
20h 29m
2 stops
$908United Airlines
Tue, May 12 - Wed, May 20
British Airways Logo
10:59 am - 8:05 am
ONT
-
LHR
13h 06m
1 stop
British Airways Logo
10:05 am - 4:22 pm
LHR
-
ONT
14h 17m
1 stop
$910British Airways
Sun, Aug 23 - Tue, Sep 8
United Airlines Logo
5:00 am - 9:00 am
ONT
-
LHR
20h 00m
2 stops
United Airlines Logo
9:30 am - 9:59 pm
LHR
-
ONT
20h 29m
2 stops
$911United Airlines
Sat, Aug 22 - Wed, Sep 9
United Airlines Logo
7:13 pm - 2:10 pm
ONT
-
LHR
34h 57m
1 stop
United Airlines Logo
7:30 am - 6:11 pm
LHR
-
ONT
18h 41m
2 stops
$912United Airlines
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 October.

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 $1,592 and $1,126 respectively.

Good to know

Low seasonJanuary
Cheapest flight$478
Best time to beat the crowds but there is an average 8% increase in price.
Most popular time to fly and prices are also 25% 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 $478 for a one-way ticket and $891 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?

    oneworld, SkyTeam, and Star Alliance are the airline alliances operating flights between Ontario and London Heathrow Airport, with oneworld 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 7.8.

  • 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 8466 reviews
8.1Boarding
7.9Comfort
8.5Crew
7.8Entertainment
7.2Food
Airline reviews

While they turned off most cabin lights to allow people to sleep, I was bothered by how bright the side lights still were. It was still quite bright for me in a window seat, when I wish I could have slept!

10.0 ExcellentTeresa, Apr 2026
SMF - LAX
Read more Delta reviews

While they turned off most cabin lights to allow people to sleep, I was bothered by how bright the side lights still were. It was still quite bright for me in a window seat, when I wish I could have slept!

Generally on time departures and arrivals, clean planes, sky miles membership provides great benefits (complimentary upgrades, etc).

N Everything was perfect from boarding to assistance to baggage in Tampa

Loved the crew! Sucks that we went from 1 hour and 8 minute layover to a 3 hour layover. But weather sucks like that.

Fast, lovely scenery, great info on the Delta flight screen about landmarks we were flying over. Great landing!

Long flight but comfortable and not freezing as I have experienced on Hawaiian flights to the islands. They gave us blankets just in case. Nice touch.

The return flight was great. The flight out to CDG was overbooked, and we were forced to check in a small carry-on at the get immediately before the flight, before getting out the stuff we needed on the plane.

I took seat 15A in anticipation of window seat, there is no window.

Flight late, the waited for a long time for “personal” to arrive at gate to dock the plane in Rochester. So annoying. This flight was expected, why aren’t personel available for the jet bridge?

My recent experience was excellent on Delta! I flew with Delta Comfort and I was really comfortable in my seat. I enjoyed the in-flight service. The flight attendants were so friendly and hospitable. I love the snack on the flight as well. This was my first time flying on Delta and I will definitely consider flying with them again.

As per usual when you Hit the UK it's a slow process through customs Not as efficient at Thailand for sure

The flight was delayed. The aircraft was unclean. Promised seat was not given due to change in Aircraft. Not one crew on ground was in a position to give any response. Amsterdam Airport is AVIODABLE Over crowded. Over Expensive. Poor Services.

The crew were unprofessional with a racist element. I was physically abused as well from one of the crew members

Empty seats next to me - wish it had been for a longer flight!!

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

Delay on my previous leg, had to run to catch my flight. But that happens. Overall ok.

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.

Some crew were unfriendly or in some cases just straight up rude.

Booked through Kayak Business, had a seat in middle and towards back due to booking rate, not comfortable.

Outstanding service, efficient & friendly crew, flight was safe, comfortable & on time

United Airline crews were very friendly and very attentive. 12 hours flight was gone like in a shorter one.

Food was surprisingly delicious. Space in the seat is horrible when the seating front is reclined. Movie offerings were terrible. Crew was friendly and helpful.

Flight itself excellent, but delayed so missed connection & got to destination 2 hrs later

Due to cancellation of connecting flight (Lufthansa) I didn’t fly with United

It was a red-eye, but the flight felt surprisingly quick. The seats were very comfortable, and that made resting much easier. I also want to thank the gentleman seated next to me, who graciously moved so my mom could sit beside me. We slept almost the entire way. The cabin crew was respectful in not disturbing us, while also being courteous and professional throughout. Thank you, United.

Boarding was again a "free for all". We were boarding group 4, and almost the entire plane was able to board before us. It's a shame that someone who follows the rules, gets the short end of the stick. Not fair.

It was perfect! I've never flown with United before, but I definitely will in the future

I had pre-selected a meal. I was told that it cannot be served because of some issue with the vendor. When travelling business class, I expect better service

The business class layout of chairs was weired. You are sitting directly across stranger.,

We did not have enough time to make our connecting flight. As a result, we were put onto a different airline for our second leg. The different airline was NOT comparable to British Airlines, and our arrival was significantly delayed. The actual flight on BA was amazing.

Tv screens and movie selection v good. Friendly staff. They were really worried about max capacity and room for carryons. That is never fun but i had no problem finding space when I boarded.

British Airways is an excellent travel service. Comfort, food and airline personnel.

My flight to London from Philadelphia was cancelled due to weather.

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.

Boarding was orderly, pilot and flight attendants were nice, entertainment options were good, and low sodium meals were quite tasty.

The whole experience was excellent, O can say out from Miami the best airline to travel with for any European destination. Since the ground staff to the inflight crew attention was great, service on board 10 of 10. Finally the 380 is very confortable and nice to travel.

All crew except 1 were excellent. When I asked assistance with business class seat conversion to a bed (not being familiar as never used before but have numerous times with other airlines) crew member helped very reluctantly. I should have told her that business class seat conversion is totally different in each airline such as Delta, New Zealand Air and United. Sorry it was my 1st time with America Airlines. Now I know, I won't bother asking assistance in future.

The seats in Premier Economy were very comfortable. The food was better than average. The way British Airways handled our seating was atrocious.

Flight delayed, connection was not at gate listed and so missed, staff were rude at Heathrow, phone tree stupid and difficult, took me 21 actual hours to reach my destination. Almost lost my hotel reservation after walking in a strange city alone after midnight because they would not put me up in a hotel at sfo or heathrow. I will never fly BA again and will tell all people and Instagram followers never to fly BA.

Overall ok. Best part has always been the sundae dessert.

I’ve never been on a trans-Atlantic (or Pacific) flight where the seats don’t recline—not even a little. I asked my seat mate when BA starting doing this and he said “Oh, a few years ago.” I couldn’t sleep, with my head falling forward waking me continuously, and came off the plane incredibly stiff. I booked a Premium Economy seat to get a more comfortable seat, which was worse than most basic Economy seats I’ve ever booked.

Wish the food and overall service was better. They treat Business class passengers same as economy

They had us seating down for one hour just waiting on the plane

Flying with BA is always a good experience—even in economy class. It is better if in business and first class. Timely, breeze through security and timely connections

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

Information on your arrival and departure airports