ONT - LHR

$434 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 7/11. 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
Tue 10/6Tue 10/13
ONT - LHR • 1 stop
Cheapest one-way
$434
JetBlue
Sat 7/11
ONT - LHR • 1 stop
Top airlines
Cheapest • from $891 (round-trip)
Best reviews • 7.9 score
Airline reviews
Airline reviews
+1
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Airline reviews
Airline reviews
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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 19m (one-way)
Insights
Insights
Insights
Insights
When to travel
Cheapest • 31% price drop
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
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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 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, Oct 6 - Tue, Oct 13
Iberia Logo
7:20 am - 9:00 am
ONT
-
LHR
17h 40m
1 stop
Iberia Logo
6:15 am - 6:57 pm
LHR
-
ONT
20h 42m
2 stops
$891Iberia
Mon, Aug 3 - Thu, Aug 20
Delta Logo
12:55 pm - 10:00 am
ONT
-
LHR
13h 05m
1 stop
Delta Logo
6:30 am - 6:29 pm
LHR
-
ONT
19h 59m
2 stops
$893Delta
Mon, Aug 3 - Thu, Aug 20
Delta Logo
10:00 pm - 6:25 am
ONT
-
LHR
24h 25m
1 stop
Delta Logo
6:30 am - 6:29 pm
LHR
-
ONT
19h 59m
2 stops
$895Delta
Mon, Nov 2 - Tue, Nov 17
United Airlines Logo
7:00 am - 5:55 am
ONT
-
LHR
14h 55m
1 stop
United Airlines Logo
6:35 am - 8:20 pm
LHR
-
ONT
21h 45m
2 stops
$896United Airlines
Mon, Aug 3 - Thu, Aug 20
Delta Logo
7:05 am - 10:20 am
ONT
-
LHR
19h 15m
2 stops
Delta Logo
6:30 am - 6:29 pm
LHR
-
ONT
19h 59m
2 stops
$898Delta
Mon, Aug 3 - Thu, Aug 20
Delta Logo
12:55 pm - 1:05 pm
ONT
-
LHR
16h 10m
2 stops
Delta Logo
6:30 am - 6:29 pm
LHR
-
ONT
19h 59m
2 stops
$900Delta
Sun, Aug 23 - Tue, Sep 8
Delta Logo
11:55 am - 1:50 pm
ONT
-
LHR
17h 55m
2 stops
Delta Logo
6:30 am - 10:40 pm
LHR
-
ONT
24h 10m
2 stops
$902Delta
Wed, Sep 9 - Wed, Sep 16
British Airways Logo
1:31 pm - 10:30 am
ONT
-
LHR
12h 59m
1 stop
British Airways Logo
2:25 pm - 9:08 pm
LHR
-
ONT
14h 43m
1 stop
$903British Airways
Wed, Jul 22 - Wed, Aug 19
KLM Logo
1:00 pm - 10:00 am
ONT
-
LHR
13h 00m
1 stop
KLM Logo
10:55 am - 4:24 pm
LHR
-
ONT
13h 29m
1 stop
$905KLM
Tue, Oct 6 - Tue, Oct 13
Air Canada Logo
5:00 am - 10:00 am
ONT
-
LHR
21h 00m
2 stops
Air Canada Logo
9:30 am - 8:52 pm
LHR
-
ONT
43h 22m
2 stops
$908Air Canada
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 $1,245 respectively.

Good to know

Low seasonJanuary
Cheapest flight$434
Best time to beat the crowds but there is an average 6% increase in price.
Most popular time to fly and prices are also 29% 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 $434 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 8454 reviews
7.2Food
7.8Entertainment
8.1Boarding
8.5Crew
7.8Comfort
Airline reviews

The Boarding process was great. Particularly since my wife and I require assistance. The flight attendants were amazing. We travel frequently; they honestly were a cut above. 😀

8.0 ExcellentMichael, May 2026
SEA - LHR
Read more Delta reviews

The Boarding process was great. Particularly since my wife and I require assistance. The flight attendants were amazing. We travel frequently; they honestly were a cut above. 😀

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?

Brand new plane lots of room the snack was very flavourful and enjoyable

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.

Late plane. Only one crew on the ground so we b had to wait for Denver flight to come in, board, and depart. At 78 yrs of age I was not pleased trying to get my connection. What really made me angry was the notification you sent me to hurry up or I would miss my connection. Why tell me to hurry up when you got me in late. It was not a good way of treating customers.

My flight time was changed without any notification to me which ruined my time sensitive plans so I ended up completely changing my travel plans and no reimbursement.

No screens or meal options. Freezing cold. Dirty seats. Left late.

Cree was organized and pleasant. Plane had good seating but as it’s a shuttle toilets hadn’t been thoroughly cleaned (eg. bins too full)

I liked that my son and I were reseated next to each other (we had different bookings). I liked that it was a directg flight and mostly on time. I liked that you provided pillows and blankets. Flight attendants were generally courteous. The messaging through wifi did not work well. The food was not good. Seats are very narrow and I felt slightly claustraphobic in the window seat.

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.

Premium Economy Good crew, good service, excellent food. Seat back screen just not bright enough.

Flight was delayed an no one cares, or try to help passengers to get the conexión.

Our flight was cancelled while we are on our way to the airport. So, no notice. We were rescheduled to another airline with a 2 hour later takeoff and so arrived at our destination on time. We pre-paid American Airlines $190 to upgrade our seats. No refund. So no use for AA or Kayak.

Terrible, horrible, disappointing- without telling us they changed planes and moved and separated our seats to opposite sides - said they changed seats putting us together - got to airport to find no, they did not - we sat opposing sides of plane - food overly salty to inedible, never saw stewardess but once - it was terrible

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.

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.

3.5 hr delay leaving Pittsburgh, notifications for which were incomplete and untimely. Connecting flight was automatically switched to one requiring more than a 30 hour layover! After waiting in a long queue, customer service reduced layover to 11 hours and also set up an earlier standby. The standby had empty seats, but the gate agent couldn't change our tickets! On top of all that my luggage was lost and has yet to even be located, much less returned 5 (FIVE!) days later. Too bad there's no rating below poor.

Canceled flight late London to Florence. Help at airport very poor. Treated poorly. Had to sleep in the airport. Lost bags- still do not have them. Horrible. I should be reimbursed!

The seats are extra cramped if you are taller than 5’8! Spring for the extra legroom seats for sure if you have a long flight!

Very disappointed with British Airways. It has been over 24 hours and I still have not received my checked baggage or any proper update. Customer support has been unresponsive, making the situation even more frustrating. Poor baggage handling and lack of communication seriously impacted my travel experience.

Flight was good but temp in the cabin was cold.

I like American Airlines and their safety record. They provide quality service and a feel safe enough to prefer American Airlines over other carriers even if I have to pay a little more.

Cancelled flight and re booked seats were a downgrade. British Airways said the upgrade was t available but when I checked it was but then they wouldn’t make it right

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

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.

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

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

Information on your arrival and departure airports