ONT - LHR

$316 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 9/9. 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

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.
Travelers love KAYAK
41,299,237 searches in the past 7 days on KAYAK

Save 20% or moreCompare multiple travel sites with one search.

Track pricesNot ready to book? Create a price alert for when prices drop.

Bundle and saveSave money when you bundle your flight + hotel.

Filter your dealsChoose cabin class, free Wi-Fi and more.

Flights Deals
Useful Info
Flights 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

Wed, Sep 24 - Thu, Oct 16
 Logo
1:15 pm - 9:50 amONT-LHR
12h 35m1 stop
 Logo
10:55 am - 4:14 pmLHR-ONT
13h 19m1 stop
Wed, Aug 20 - Wed, Aug 27
Delta Logo
11:45 am - 1:30 pmONT-LHR
17h 45m1 stop
Delta Logo
11:45 am - 10:40 pmLHR-ONT
18h 55m2 stops
$527Delta
Find Deal
Tue, Aug 12 - Tue, Aug 19
Delta Logo
7:05 am - 11:00 amONT-LHR
19h 55m2 stops
Delta Logo
6:15 am - 4:08 pmLHR-ONT
17h 53m2 stops
$531Delta
Find Deal
Tue, Sep 2 - Wed, Sep 17
Iberia Logo
2:57 pm - 12:45 pmONT-LHR
13h 48m1 stop
Iberia Logo
6:30 am - 10:33 pmLHR-ONT
24h 03m2 stops
$639Iberia
Find Deal
Mon, Aug 25 - Mon, Sep 1
Iberia Logo
12:47 pm - 2:25 pmONT-LHR
17h 38m1 stop
Iberia Logo
8:00 pm - 10:48 pmLHR-ONT
34h 48m2 stops
$653Iberia
Find Deal
Sun, Aug 3 - Tue, Aug 19
American Airlines Logo
4:45 pm - 12:50 pmONT-LHR
12h 05m1 stop
American Airlines Logo
12:00 pm - 6:24 pmLHR-ONT
14h 24m1 stop
$656American Airlines
Find Deal
Sun, Aug 3 - Tue, Aug 19
United Airlines Logo
1:34 pm - 9:40 amONT-LHR
12h 06m1 stop
United Airlines Logo
2:50 pm - 8:43 pmLHR-ONT
13h 53m1 stop
$658United Airlines
Find Deal
Wed, Aug 20 - Fri, Sep 5
British Airways Logo
12:46 pm - 10:50 amONT-LHR
14h 04m1 stop
British Airways Logo
12:00 pm - 6:54 pmLHR-ONT
14h 54m1 stop
$661British Airways
Find Deal
Wed, Aug 13 - Thu, Aug 21
United Airlines Logo
1:19 pm - 10:25 amONT-LHR
13h 06m1 stop
United Airlines Logo
2:50 pm - 8:43 pmLHR-ONT
13h 53m1 stop
$663United Airlines
Find Deal
Sat, Aug 16 - Fri, Aug 29
British Airways Logo
11:59 pm - 9:00 amONT-LHR
25h 01m1 stop
British Airways Logo
4:25 pm - 12:07 amLHR-ONT
15h 42m1 stop
$688British Airways
Find Deal
Useful Info

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’s the cheapest day of the week to fly from Ontario to London Heathrow Airport?

The average price of all round-trip flights from Ontario to London Heathrow Airport clicked on KAYAK for each day over the last 12 months.

If your flying dates are flexible, you should consider flying to London Heathrow Airport on a Wednesday, as we generally find the cheapest rates on that day for this route. On the other hand, Saturday is the most expensive day to fly from Ontario to London Heathrow Airport. For your return ticket, we recommend flying on a Tuesday and avoiding Mondays for the best deals.

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 March, where tickets cost $669 (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 $1,027 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 5 weeks before departure. For the absolute cheapest price, our data suggests you should book 16 weeks before departure.

Good to know

Low seasonFebruary
High seasonSeptember
Cheapest flight$316
Best time to beat the crowds with an average 19% drop in price.
Most popular time to fly and prices are also 14% 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 $316 for a one-way ticket and $526 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 $796 and an overall rating of 8.0, Delta is the most popular choice. KLM is also a great choice for the route, with an average price of $763 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.
8.0
DeltaOverall score based on 7982 reviews
8.5Crew
7.9Entertainment
8.2Boarding
7.3Food
7.9Comfort
Airline reviews

My husband upgraded our seats and I don't know if it was due to the type of planet was or if they didn't upgrade our seats. We were supposed to be in I believe comfort seats and they were just as tight as any other seat- no leg room and we are very tall people but at least it wasn't extremely cold. My husband did put in a complaint about our seating because he paid extra and if we would have known that the space and the tightness would have been the same, we just would have gotten the emergency row emergency row seats that we normally get. We love Delta but both our flights coming home we're not good. Oh I forgot to mention that on our flight to Hawaii our luggage wheels got broke and we had to purse new luggage on vacation then we never had this problem so we didn't know protocol and reported it after we got home only for them to tell is we only had 24hrs to report the damage. Not sure what was going on with Delta this vacation trip.

4.0 OkayMrs., Jul 2025LAX - RDU
Read more Delta reviews

My husband upgraded our seats and I don't know if it was due to the type of planet was or if they didn't upgrade our seats. We were supposed to be in I believe comfort seats and they were just as tight as any other seat- no leg room and we are very tall people but at least it wasn't extremely cold. My husband did put in a complaint about our seating because he paid extra and if we would have known that the space and the tightness would have been the same, we just would have gotten the emergency row emergency row seats that we normally get. We love Delta but both our flights coming home we're not good. Oh I forgot to mention that on our flight to Hawaii our luggage wheels got broke and we had to purse new luggage on vacation then we never had this problem so we didn't know protocol and reported it after we got home only for them to tell is we only had 24hrs to report the damage. Not sure what was going on with Delta this vacation trip.

Crew was excellent. Comfort seats not as nice as other kinds of planes.

It was a great flight and the stewards and stewardess were all kind and accommodating!! The seats were comfortable and entertainment screen excellent!

There are 4 flights in consecutive gates with about the same departure time. Two flights were boarding at the same time. One was delayed or boarding would be happening at the same time. I am not sure what Delta and LAX need to do to have a better layout at the end of Terminal 2

There was a security issue at the airport and we were unable to land. We circled endlessly and then landed at another airfield for fuel. We then circled the airport again, almost landed but didn’t fully touch down before circling again. I am thankful to the crew for keeping us safe- the issue was the airline and staff at the airport getting us seats on our connecting flights. That part was hours of searching for someone and getting in double my steps.

Most aspects were good however if they assign boarding zones they ought to enforce them or why bother? My luggage from SAN-JFK-MAD was lost in NY so I without my main bag for two days upon arrival in Spain. They were helpful in tracking it and eventually delivered it to my hotel. The flub was because of a delay upon arrival in NYC. I had booked 2 1/2 hours between flights but we had to hold on the taxiway for an hour after landing while waiting for a clear gate which likely caused the baggage error.

Excellent flight, the planes were newer, they did a nice job with boarding, great service overall.

It would be nice if was given wires ear buds. Overall was a good experience was able to sleep on the plane

737-800 in first class was pretty dumpy. Seat had an uncomfortable angle, storage under the seat was blocked so even my very modest backpack didn't fit, power outlet was flaky. Weird tiny seat pockets that couldn't hold a gallon ziploc bag, emesis bag missing, etc. etc. No in-flight service due to turbulence. Crew was excellent, boarding was smooth despite a full flight.

Delta flight was on time, seats were comfortable, and crew was nice.

Boarded plane and then delayed 1.5 hours while on the plane

Although the flight was delayed the crew and the flight itself were very good. Couldn't fault anything and after the disappointment of being abandoned in the US by BA it was a welcome relief to travel with United

Horrific. They missed my connecting flight to San Diego. I didn’t get there until Monday at 9am when I had a mandatory court settlement conference scheduled at 6am since we had parties on the east coast. This caused many issues. All because United apparently forgot to hold the doors open until my flight landed that only had a 10 minute delay. This was the last flight to Southern California. So I couldn’t even rent a car to finish the trip. United cannot be trusted when traveling on specific days and times since weather didn’t have anything to do with the delays.

Really good 😊 the woman at the gate entrance was a little rude checking in our carry-on but i dont think she worked for the airline, she worked for the airport at sacramento, other than that amazing.

it was so bad. I tried to board my flight from vancouver to saskatoon. And to my surprise they did not board me cause the flight was changed and no email was send to me. and on my boarding pass which i got from seattle says different flight. I did not knew anyone from Vancouver, air canada crew was rude, i asked for today flight but they were rude and i had early morning dental appointment in saskatoon. I was so much in pain and my whole day is wasted today. and i suffered alot. They did provide me hotel but they did not provide me any food. I am really really disappointed first time had so bad experience with air canada. I may think twice to book it again. If i can get any reply or any composition that would be great. Thanks

Very comfortable (upgraded to business class). The audio on my screen didn’t work, but I managed to play the audio through my phone while watching the screen.

The food was the worst I’ve had on any flight I’ve ever been on.

I was supposed to be on business class at first class from Denver back to Miami due to weather changes. I missed my connection and it’s put on a flight to Fort Lauderdale. Instead of honoring my business class/1st class ticket, they put me in coach, but there were two first class seats open. I think it’s absolutely disgusting that I paid for first class $1300 ticket and they put me in economy and they had to open seats available and I have still not been refunded the difference. I ended up having to eat a snack box instead of the meal I was supposed to get and did not get home till 2 AM so I think that’s a little pathetic that I had to live off crackers for dinner And my poor dog ate some cheese and salami. Oh yes, apparently when they switched me to the new flight they forgot to mention I had a service dog

Flight was late as pilot crew had to land at different airport in their previous flight. Passengers boarded and had to wait for pilots inside plane. Series of incomplete and unnecessary announcements by an annoying voice, rather than complete, informative announcements.

Breakfast was not loaded at SFO due to catering company change. Seems like a major airline at a major hub would have thought of something else or warned passengers to pick up food before boarding a 3 hour flight.

The chair cushions may need an upgrade. I have been noticing they are so worn out, thin so you’d sit in a dip 😄. Other than that, all was an enjoyable trip. Thanks AA!

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

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

The chicken adobo was a little too spicy but good otherwise. My personal opinion. Movie selection could be improved, too many horror movies. Could add a few more chick flicks! The flight was bumpy at times. We arrived a little early too! Flight attendants friendly.

Again flight was awesome except British Airways lost both gate checked luggage’s. Still missing

really bad they refused to check in luggages that I had purchased, even showing them the transaction receipt from british airways app the staff in miami was MEDIOCRE

Crew was great and responsive. Entertainment quit working with about 4 hours remaining on the flight. My seat cushion was broken.

Not very good , the stewardess were unfriendly and they don't like to be bothered. Cos was a night flight and they need to sleep.

British Airways staff are very polite and willing to help.

ground crew and check-in was pathetic - insisted on charging me for luggage even though the ticket said it was already included. They also accidentally sent my luggage through without a luggage tag and had to retrieve it. Generally, it was like a bad movie.

Moved the flight an hour later, were not reliable about confirmation, website didn't work, no gate information, boarding was a mad house. Flight itself was fine and short. Organization needs work.

The app on phone and the online check in is not good, it would not give me the option of Spain or Madrid City in the drop down menu and I couldn't move forward with online check in.

Flight was delayed 3 hours and 15 minutes. The delay caused me to miss my tour group due to arriving late.

As always a terrible experience. AA stole a day from my vacation days planned to be spent with my Family. Response: delays related to weather issues.

It was a wonderful experience with great food, great staff, and no difficulties boarding!

Paid for my seat 4 months ago. Did not pay the extra for specific seat assignment ( never have and never was a problem). Could not electronically check in (found out it was due to overbooking and that unassigned seats get bumped first - never happened to me before). Luckily, did make the flight. Very stressful - would have been extremely disruptive for my travel plans. UK Visa - never notified by Kayak or BA that a visa was required. Had to spend 15 minutes to download and complete app at the flight counter and pay $25, and was told they would let me know in 3 days if I would get it (flight landing in 10 hours from when I completed app). Luckily, visa was approved before landing. Unnecessary stress created here. Food - main meal, curry chicken barely palatable with unrecognizable vegetable. Desert cup, cheesecake, also barely palatable. Salad cup was good. Small water offered only 3 times (before main meal, at main meal, at morning snack) - not nearly enough for long flight.

From boarding, to attention in flight, I couldn’t fault it.

Not having to check carry on bags when plane wasn’t full. (The told us it was)

I was in business class for the 8 hour flight where: 1. The WiFi did not work 2. The entertainment system did not work 3. We were told there were no hot drinks for the entire flight

Flight was good but seat in 12D was not comfortable, better on the Airbus 321 from Tampa to Charlotte. No breakfast was served before landing in zLonfon only a coffee and orange juice.

I was transferred to an American Airlines flight. The boarding was late and unorganized. The seating was extremely tight and uncomfortable. Will not use AA again.

The entertainment selection was ok, but overall not bad! The crew was great.

Good crew and boarding process. Horrible food and one of the most uncomfortable aircraft seats I have ever sat in. The cabin temperature was warm which made it hard for my family to sleep.

The check-in of my luggage was terrible. When purchased my tickets, one luggage and one carry-on was part of the fight. My flight was switched from British to American Airline. During check-in of luggage at the airport, I was denied and had to pay extra $75. How do I get reimbursed for this extra luggage payment?

More Indian vegetarian food options would have been better Availability of seat selection free of charge 72 hours before departure would be great

This was the second time on BA, food terrible, bathrooms gross,( granted, that was mostly due to the disgusting children urinating all over it)boarding was late and disorganized. No gate issued until last minute st Heathrow, bad system, caused undue stress. Seats were painful, that's what you get for traveling like a poor in economy, right BA? Should have been able to afford business or first class if you want to actually be able to walk upright without back pain after a trip.

This was the second time on BA, food terrible, bathrooms gross, boarding late and disorganized. No gate issued until last minute st Heathrow, bad system, caused undue stress.

The flight was delayed twice and because of that, we missed our connecting flight. British Airways then attempted to put us on the last flight to Milan from London which would have kept us in the airport for 12 hours. We had to speak to several levels of bureaucracy until BA management let us fly on a flight that only kept us in the airport for two hours. If there was an earlier flight, why weren’t we put on that flight from the start? Unacceptable behavior from what was once my favorite carrier.

The payment system was not working so was unable to connect wifi the entire flight

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

Information on your arrival and departure airports

Not what you’re looking for? Find thousands of other hotels, flights, car rentals and package deals with KAYAK.