ONT - LHR

$319 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 10/11. 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
$826
Typical prices: $936-$628
British Airways, Iberia
Sun 9/27Wed 10/7
ONT - LHR • 1 stop
Cheapest one-way
$319
Typical prices: $468-$505
British Airways
Sun 10/11
ONT - LHR • 1 stop
Top airlines
Cheapest • from $828 (round-trip)
Best reviews • 7.8 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 $580 (round-trip)
Shortest trip • 12h 20m (one-way)
Insights
Insights
Insights
Insights
When to travel
Cheapest • 32% 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

Sun, Sep 27 - Wed, Oct 7
Multiple Airlines Logo
1:05 pm - 3:05 pm
ONT
-
LHR
18h 00m
1 stop
Multiple Airlines Logo
10:50 am - 11:06 pm
LHR
-
ONT
20h 16m
2 stops
$826Multiple Airlines
Sun, Sep 27 - Wed, Oct 7
British Airways Logo
1:05 pm - 3:05 pm
ONT
-
LHR
18h 00m
1 stop
British Airways Logo
8:55 am - 9:08 pm
LHR
-
ONT
20h 13m
1 stop
$828British Airways
Wed, Sep 9 - Sat, Sep 19
British Airways Logo
2:22 pm - 12:50 pm
ONT
-
LHR
14h 28m
1 stop
British Airways Logo
8:55 am - 10:37 pm
LHR
-
ONT
21h 42m
1 stop
$829British Airways
Wed, Nov 11 - Wed, Nov 18
Multiple Airlines Logo
10:47 am - 12:15 pm
ONT
-
LHR
17h 28m
1 stop
Multiple Airlines Logo
7:40 pm - 10:23 pm
LHR
-
ONT
34h 43m
2 stops
$831Multiple Airlines
Tue, Nov 3 - Tue, Nov 10
Multiple Airlines Logo
6:00 am - 7:10 am
ONT
-
LHR
17h 10m
2 stops
Multiple Airlines Logo
11:45 am - 9:11 pm
LHR
-
ONT
17h 26m
1 stop
$832Multiple Airlines
Sun, Sep 27 - Wed, Oct 7
Multiple Airlines Logo
5:00 am - 6:30 am
ONT
-
LHR
17h 30m
2 stops
Multiple Airlines Logo
9:15 am - 11:06 pm
LHR
-
ONT
21h 51m
2 stops
$834Multiple Airlines
Sun, Sep 27 - Wed, Oct 7
Multiple Airlines Logo
5:00 am - 10:00 am
ONT
-
LHR
21h 00m
2 stops
Multiple Airlines Logo
9:15 am - 11:06 pm
LHR
-
ONT
21h 51m
2 stops
$835Multiple Airlines
Tue, Sep 1 - Sat, Sep 12
Multiple Airlines Logo
6:00 am - 6:35 am
ONT
-
LHR
16h 35m
2 stops
Multiple Airlines Logo
8:55 am - 10:37 pm
LHR
-
ONT
21h 42m
1 stop
$837Multiple Airlines
Wed, Sep 2 - Wed, Sep 16
Alaska Airlines Logo
6:02 am - 3:05 pm
ONT
-
LHR
25h 03m
1 stop
Alaska Airlines Logo
5:00 pm - 2:16 pm
LHR
-
ONT
29h 16m
1 stop
$841Alaska Airlines
Fri, Sep 4 - Mon, Sep 14
Multiple Airlines Logo
7:13 pm - 6:30 am
ONT
-
LHR
51h 17m
2 stops
Multiple Airlines Logo
4:25 pm - 9:29 am
LHR
-
ONT
25h 04m
1 stop
$842Multiple 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 September.

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 $1,234 respectively.

Good to know

Low seasonJanuary
Cheapest flight$319
Best time to beat the crowds but there is an average 5% increase in price.
Most popular time to fly and prices are also 30% 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 5 days, the lowest price for a flight from Ontario to London Heathrow Airport was $320 for a one-way ticket and $826 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 7.8, 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.
7.8
DeltaOverall score based on 8395 reviews
8.5Crew
7.8Entertainment
7.8Comfort
8.1Boarding
7.2Food
Airline reviews

The crew were efficient. The pilots seemed professional. It was a bit chilly in our seats. The sheet provided weren’t very helpful.

8.0 ExcellentAnonymous, May 2026
ATL - LHR
Read more Delta reviews

The crew were efficient. The pilots seemed professional. It was a bit chilly in our seats. The sheet provided weren’t very helpful.

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.

Outstanding even though the 330 was one of the oldest in the fleet. The difference was the attentiveness and responsiveness of a really experienced flight attendant. For airline food great variety of interesting choices and good tastes supported by a good wine selection.

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

There were no charge points for phones on the economy seats. The seats were comfortable overall. Food was okay.. flight was on time

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

Crew is not the cheerful type. very slow meal service (this is their style as have flown this many times)

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.

Horrifying Almost 2 million miles. Bring your own food and drink. One coffee or drink every three hours. Have to order meals on app more than 24 hours ahead Tiny and dirty bathrooms

Flight was delayed but more than 90 minutes. This caused me to miss my available windows for pick-up by a friend. I had to pay $125 for an uber back home from the airport which was an added expense that I had not budgeted for my trip. Staff was friendly.

Seat pitch is horrible especially on the 15 hour flight. Gate crew at SFO was Outstanding. The flight crew was also great.

Easy of boarding, helpfully staff at check in, surprisingly comfortable seating

Lost of requested seat assignments. Lost my husband's meal choice

My service dog and I were asked to deplane just before they closed the door - clearly very last minute they couldn’t find the documentation that I have filled out many many times before that is for flying service animals. I purposely purchase 3seats (a whole row) since he is large and not all passengers want to sit next to a dog on a cross country flight. The plane departed with my husband on it!!! They made me fill out a hard copy of the same form and had to reschedule me on a later flight where they could find 3 seats together!! I’ve done this so many times before - clearly the error was on their part in a technology glitch - but really people - do better!! Very traumatic - and my husband had to wait for us when he landed ….so bad. Poor pup was confused and tired.

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)

B-class on an old plane with antiquated amenities and poor service. Landed in Rome w/o bag that didn’t make the connection (plenty of time in London). Bag will come to hotel NOT the day it lands but the following night!! Still waiting for bag…BA had nothing to offer in support and couldn’t even tell me their comp, told to submit receipts and then I’ll learn what is or isn’t covered.

It's a long flight and that is always difficult. I was comfortable and well. The movies available were great and the crew was good.

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.

Boarding process was chaotic. Confusion over Boarding gates: gate 55 or gate 56 ???. Unnecessary standing in long lines to board. Better to call out Boarding groups one at a time and everyone else to sit. Airline only has 2 Boarding groups 1-3 and 4-9. That causes over crowding and chaos

Lady next to me was coughing profusely the entire flight, other lady moved seats because of it, 8 hours of that during an overnight flight is a bit much.

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.

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

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

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

Information on your arrival and departure airports