ONT - LON

$337 Find Cheap Flights from Ontario to London

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 London departing on 7/6. 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.
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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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Flights Deals

Cheap Flights from Ontario to London (ONT-LON)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Ontario to London 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 London

qua, ago 20 - qua, ago 27
Delta Logo
11:45 am - 1:30 pmONT-LHR
17h 45m1 stop
Delta Logo
6:15 am - 10:42 pmLHR-ONT
24h 27m2 stops
$549Delta
Find Deal
qua, ago 20 - qua, ago 27
Delta Logo
9:50 am - 1:30 pmONT-LHR
19h 40m2 stops
Delta Logo
6:15 am - 4:18 pmLHR-ONT
18h 03m2 stops
$553Delta
Find Deal
seg, out 27 - qua, nov 12
KLM Logo
1:00 pm - 10:00 amONT-LHR
14h 00m1 stop
KLM Logo
10:45 am - 4:14 pmLHR-ONT
13h 29m1 stop
$557KLM
Find Deal
ter, ago 12 - qui, ago 28
KLM Logo
1:15 pm - 9:50 amONT-LHR
12h 35m1 stop
KLM Logo
10:55 am - 4:18 pmLHR-ONT
13h 23m1 stop
$558KLM
Find Deal
dom, ago 31 - qui, set 11
United Airlines Logo
6:50 pm - 7:25 amONT-LHR
28h 35m1 stop
United Airlines Logo
7:30 am - 5:29 pmLHR-ONT
17h 59m2 stops
$670United Airlines
Find Deal
ter, set 2 - sex, set 12
Iberia Logo
2:57 pm - 12:30 pmONT-LHR
13h 33m1 stop
Iberia Logo
4:25 pm - 11:36 pmLHR-ONT
15h 11m1 stop
$672Iberia
Find Deal
ter, ago 5 - sex, ago 29
British Airways Logo
4:45 pm - 12:50 pmONT-LHR
12h 05m1 stop
British Airways Logo
3:40 pm - 9:39 pmLHR-ONT
13h 59m1 stop
$677British Airways
Find Deal
qua, ago 27 - sex, set 12
United Airlines Logo
1:19 pm - 12:20 pmONT-LHR
15h 01m1 stop
United Airlines Logo
2:50 pm - 8:43 pmLHR-ONT
13h 53m1 stop
$678United Airlines
Find Deal
ter, set 2 - ter, set 9
Iberia Logo
2:57 pm - 2:25 pmONT-LHR
15h 28m1 stop
Iberia Logo
12:00 pm - 9:56 pmLHR-ONT
17h 56m1 stop
$714Iberia
Find Deal
ter, ago 5 - qui, ago 14
British Airways Logo
4:45 pm - 12:50 pmONT-LHR
12h 05m1 stop
British Airways Logo
3:40 pm - 9:39 pmLHR-ONT
13h 59m1 stop
$715British Airways
Find Deal
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KAYAK's insights & trends for Ontario to London flights

Get data-powered insights and trends into flights from Ontario to London 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?

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

For Ontario to London, Wednesday is the cheapest day to fly on average and Saturday is the most expensive. Flying from London back to Ontario, the best deals are generally found on Tuesday, with Monday being the most expensive.

What is the cheapest month to fly from Ontario to London?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Ontario to London, 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 is August, where tickets cost $658 (return) on average. On the other hand, the most expensive months are June and December, where the average cost of round-trip tickets is $1,108 and $883 respectively.

How far in advance should I book a flight from Ontario to London?

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, 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, you should book around 3 weeks before departure. For the absolute cheapest price, our data suggests you should book 16 weeks before departure.

Good to know

Low seasonJanuary
High seasonJune
Cheapest flight$337
Best time to beat the crowds with an average 13% drop in price.
Most popular time to fly with an average 42% increase in price.
Flight from Ontario to London Gatwick Airport

When to book flights from Ontario to London

Are your dates flexible? Find out the best times to travel from Ontario to London 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 flights from Ontario to London

  • How can I get to the city center by public transport after my flight from Ontario to London?

    Upon arrival at London Heathrow Airport from Ontario, you can easily reach the city center using public transportation. Take the Heathrow Express train to Paddington Station, which operates every 15 minutes. From Paddington, you can transfer to the London Underground and take the Bakerloo Line or Circle Line to reach the city center.

  • Can I pre-book my seat on WestJet flights from Ontario to London?

    Yes, you can pre-book your seat on WestJet flights from Ontario to London. WestJet offers the option to select your preferred seat in advance, allowing you to secure your desired seating arrangement for a more comfortable journey. By accessing their online booking portal or contacting their customer service, you can make seat reservations according to your preferences and availability.

  • Which kid-friendly amenities does WestJet have on flights from Ontario to London?

    WestJet offers several kid-friendly amenities on flights from Ontario to London. These amenities include children's entertainment options such as movies, TV shows, and games suitable for different age groups. They also provide complimentary activity packs with coloring books, crayons, and puzzles to keep young travelers engaged during the flight.

  • What are the baggage restrictions when flying Virgin Atlantic from Ontario to London?

    The baggage restrictions when flying Virgin Atlantic from Ontario to London include a checked baggage allowance of two pieces weighing up to 50 lbs each in Economy class. Additionally, passengers are allowed one carry-on bag weighing up to 22 lbs and one personal item such as a laptop or handbag.

  • What is the cheapest flight from Ontario to London?

    In the last 3 days, the lowest price for a flight from Ontario to London was $337 for a one-way ticket and $549 for a round-trip.

  • Do I need a passport to fly between Ontario and London?

    A passport is required to fly from Ontario to London.

  • Which aircraft models fly most regularly from Ontario to London?

    We unfortunately don’t have that data for this specific route.

  • Which airline alliances offer flights from Ontario to London?

    SkyTeam, Star Alliance, and oneworld are the airline alliances operating flights between Ontario and London, with SkyTeam being the most commonly used for this route.

  • Which is the best airline for flights from Ontario to London, Delta or United Airlines?

    The two airlines most popular with KAYAK users for flights from Ontario to London are Delta and United Airlines. With an average price for the route of $854 and an overall rating of 8.0, Delta is the most popular choice. United Airlines is also a great choice for the route, with an average price of $840 and an overall rating of 7.4.

  • How does KAYAK find such low prices on flights from Ontario to London?

    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.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Ontario to London?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to London 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?

    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 with an airline and back to Ontario with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Ontario to London?

    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 from Ontario up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

KAYAK’s top tips for finding a cheap flight from Ontario to London

  • Common layover options for Air Canada flights from Ontario (ONT) to London (LON) may include stopovers in major hub cities such as Toronto, Montreal, or Ottawa. These layovers often provide convenient connections for passengers, allowing them to change planes and continue their journey to London.
  • Additionally, Air Canada offers a special food service called "Chef's Menu" on its flights from Ontario to London. Passengers can enjoy a delectable selection of culinary delights prepared by renowned chefs. The menu features a range of gourmet dishes using fresh, locally sourced ingredients, ensuring a delightful dining experience in the skies. From appetizers to main courses and desserts, Air Canada's Chef's Menu promises to satisfy the taste buds of travelers throughout their journey.
  • Air Canada offers a variety of in-flight entertainment options on its flights from Ontario to London. Passengers can enjoy a selection of movies, TV shows, and music, with a wide range of genres to choose from. Additionally, the airline provides personal screens with touch controls, offering a seamless and enjoyable viewing experience.
  • WestJet assists passengers with disabilities traveling from Ontario to London. They offer wheelchair assistance, accessible seating options, and priority boarding. Passengers can request special services such as mobility aids or medical equipment during their journey. WestJet's trained staff is available to ensure a comfortable and safe travel experience for passengers with disabilities, addressing their specific needs and providing necessary support throughout the journey.
  • You can change your seat when flying with WestJet from Ontario to London. Seat changes are subject to availability, and you can make the change either during the booking process or by accessing your reservation online. Alternatively, you can contact WestJet's customer service for assistance with seat changes.

Top 5 airlines serving from Ontario to London

 
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 London? 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 7950 reviews
8.2Boarding
7.3Food
8.5Crew
7.9Comfort
7.9Entertainment
Airline reviews

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.

6.0 GoodWalter, May 2025ONT - SLC
Read more Delta reviews

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.

Bathrooms dirty sinks clogged. No one seemed to clean them. Plane very old

Thank you for not flipping the plane on the run way. You guys get a 5 star rating for the flight!!!

Boarding is, as it always is… horrible. Gate lice. Slow moving zones. Too many people with carry ons

It was terrible, if they ran flights on time it would make a big difference.

Delta seems to be improving in many areas, except they are super bad with the food available. Bring back normal food service on long flights.

All fine save for the abominable catering. Really gone downhill. We found it all inedible.

I actually received a notification from kayak on email but not one by text from Delta when my departure gait changed and I almost missed my flight

New boarding doesn't make sense. Filling front first is slow.

Boarding seemed to be organized bedlam. For what ever reason, preboarding took longer than 20 minutes. Made the plane 20 minutes late taking off. Luckily we arrived on time. Flight crew seemed very friendly. Only slight turbulence.

They hired a new catering company the same day of my flight. They botched the job by not delivering the right carts and after THREE HOURS waiting, the flight crew timed out (flight was 19 hours long and FAA rules state crew can’t work more than 14 hours long). So they CANCELED OUR FLIGHT!! Worst experience ever. Avoid UAL at all costs.

The personnel were professional and friendly. The Boeing 737 Max 9 is too claustrophobic and was very warm at both airport gates, and still warm in the air.

While the staff was pleasant and helpful, the following observations are for your awareness. There was some delay on the tarmac on take off and landing. The paid lunch/food offerings were limited. Entertainment was only available on WiFi at a cost.

get E+, a must for 5 hours flight if you are tall

The first flight was better in terms of the aircraft.

Liked fold flat bed. Didn’t like having no window. Didn’t like poor choice of food and being served dinner very late, hours after take off of a 7:40pm flight. Servers not friendly. Food horrible in business class.

Everything is good except the dinner and breakfast. The sandwich is very delicious. Toilet is clean, I only use one of them. Flight attendants are very nice. 👍👍

The gate was too far away for the connecting flight

Compared with other carriers business class for an overnight was not worth the extra expense.

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.

This particular flight wasn't very full at the back, so there were three seats available for spreading out and getting relatively comfortable

There were several issues with this flight. I have flown quite often internationally and I was surprised by the lack of presence of attendants other than meal and drink times. The food was not best but I feel that is the norm. We also had to get off the plane once in London via stairs and bus to the terminal. Anyone who had another flight had to then get another bus to another terminal. This causes me to miss my flight and have to rebook.

Unexpectedly was surprised with the space on flight in economy and the price.

I was not expecting having to pay for headphones, water and basic food in a 9 hours flight. Price for this flight was as high as any other, still I had to pay 4 lbs for a can of sprite. On top of that flight attendance gave a bothered look when I asked her for some ice for my soda. She reluctantly when to get it, brought me literally 3 cubes and walked away without looking at me to avoid another request. I couldn’t believe it. She was soooo rude. I will never book on Norse again and I will let everyone I know about this. Unforgivable, very bad customer service.

Great crew. Customer support is pretty much non existent. I had 2 tickets that were not used, the flight was overbooked. I think I should have been reimbursed for the unused tickets.

The movies were super old. The crew did not offer WATER???? 5 hours os flight and did not get WATER? Norse is the worst company I ever used and never will use again.

Why call us to board if we’re going to be made to stand in the tunnel for 20 minutes. Really hard for people with little children. Plus it took me ages to check in because my seat in Premium was overbooked so I didn’t actually have a seat. I did end up receiving my seat in Premium but there was a lot of stress and confusion beforehand. Hope is it possible to overbook seats? Especially in Premium!

We flew one way from Gatwick, London to JFK NY For 2 people $1200 and no food offered not even water. You had to buy food. Norse advertises as a low fare transatlantic airline, they may want rethink that. Crew, flight was fine. Ironically we flew American from JFK to Heathrow for $1000 (2people) and included food and drinks.

Longest check in line I have ever seen- brutal and airline personnel hustled me about the size of my bag even though I showed them that it measured exactly to the measurements posted on their site. Just super annoying- I get it - it’s a budget airline and you get what you pay for. Most of the flight were young people who seemed to have never experienced international travel. It’s worth paying for a seat otherwise you will be uncomfortable.

We flew premium on the way TO London but went back to economy for this flight. The differences I note here may be colored by changing service. The crew was professional and polite but cold on this flight and class of service. They seemed to want to have as little to do with us as possible, beyond providing the basic services in economy. The aircraft was still good though, and the pitch was about as tight as expected - manageable but no extra personal space to spare. Overall I would certainly fly Norse Atlantic again, given the opportunity.

The crew really made the difference. Some of the friendliest cabin crew I have ever encountered- they seemed genuinely happy to be there, and took pride in their airline and aircraft. The Dreamliner was quieter than legacy aircraft and while meals weren’t to our preference, they were at least something to keep us going!

I loved the ability to upgrade my seat which was worth it. The large seat and ability to recline made it comfortable to fall asleep. My only two complaints were entertainment (movie selections were old) and approx 30 mins before landing the crew started to collect the blankets despite the cabin air temperature remaining cold. Maybe wait for passengers to get off the plane before collecting the blankets.

My flights were great and the crew on them was lovely especially the London to Barcelona flight as Al & AJ were so amazingly nice. I wish they would be my crew always as they have the best customer service. Sadly both flights were delayed the first one from Vegas was because they clearly loaded the cargo wrong the plane was off balance making us 2 hours late. This made me miss my connection and sadly it was challenging rebooking while I was on the flight. I will never use Kayak again as there was no customer service number or live chat and you rebooked me on a flight 2 days later. I had my mom call BA to change it which she did after spending an hour on hold. This should not be so difficult. My second flight was an hour delayed due to not being able to disconnect the bridge from the plane but I did finally make it home.

The delay was not communicated via text and the person who helped with check in also didn’t inform me about the delay. I ended up missing my connection and it was a waste of 5 hours. The crew didn’t mention there would be someone at the gate informing of if I would be rebooked and there was no signage. Overall a very poor experience. The British Airways app was also very buggy, and didn’t work. I will avoid flying with British Airways when possible.

A little better than outward journey but mild chaos at the boarding gate because some people with boarding cards from connecting flights had cards which weren't recognised

The BA business class cabin is excellent,very comfortable for sleeping but the service could be improved.

Surly rude flight attendants. I ordered the chicken and was given a vegetarian meal with no explanation and no opportunity to change it. I tried to order another beverage and was told by the young humorless flight attendant to “wait”. And she never came back. The seats were very uncomfortable and cramped. The last time I flew British Airways was many years ago but I remember it was amazing and the crew were very charming. This was a terrible disappointment given the cost of the flight.

Nice flight, attentive crew, soft landing by the Pilot,, comfortable seat.

I paid for business class…. And was counting on the usual packet of toilettes to be provided. They were not because not enough were brought on the plane so they could t give to some and not all. So no tooth brush nor eye cover. Then NO coffee since there was no hot water. The lay I er too short because of delays and my luggage didn’t make the next flight!! It is now a day later and I am awaiting to hear if my bag has arrived. Very inconvenient!. I suppose I need to be glad that I spend over $4000 since I doubt those in coach or premium economy even made that next flight..Heathrow is the worst.

The flight from Seattle was delayed, which made me miss my connection to Florence. I was re-booked NINE HOURS LATER!!! That’s basically a vacation day lost. British Airways needs to partner with other airlines when possible to get a more realistic travel time, if delays occur. I realize there aren’t many flights to Florence from London, so I would book differently were I to return. The actual flight from Seattle was very comfortable and the crew was great, no faults there. I enjoy British Airways, this was an anomaly.

The crew could not have been more helpful, my meal was excellent, I slept peacefully until right before landing, and the BA lounge was a godsend. The only negative I encountered was the coffee both on the plane and in the lounge. Not to my taste but that’s a personal preference.

I don’t understand why a reputable airline like BA would delegate their London flights to AA. Makes no sense to me, as most domestic carriers do such a poor job these days. Terminal 3 at LHR is a total dump

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