ONT - LON

$334 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 3/25. 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

 
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
$589
Overall average: $834
British Airways
Tue 1/20Tue 2/3
ONT - LHR • 1 stop
Cheapest one-way
$334
Multiple Airlines
Wed 3/25
ONT - LHR • 2 stops
Top airlines
Delta
Cheapest • from $617 (round-trip)
Delta
Best reviews • 7.9 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
When to travel
October
Cheapest • 13% price drop
April
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
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Flight Deals
Booking Insights
Flight 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

Tue, Jan 20 - Tue, Feb 3
British Airways Logo
4:45 pm - 1:15 pmONT-LHR
12h 30m1 stop
British Airways Logo
3:00 pm - 10:48 pmLHR-ONT
15h 48m1 stop
$589British Airways
Find Deal
Mon, Dec 8 - Tue, Dec 23
KLM Logo
6:40 am - 10:30 amONT-LHR
19h 50m1 stop
KLM Logo
2:45 pm - 10:49 pmLHR-ONT
16h 04m1 stop
$596KLM
Find Deal
Tue, Feb 24 - Tue, Mar 17
Virgin Atlantic Logo
1:15 pm - 11:40 amONT-LHR
14h 25m1 stop
Virgin Atlantic Logo
2:30 pm - 10:34 pmLHR-ONT
15h 04m1 stop
$598Virgin Atlantic
Find Deal
Tue, Feb 24 - Wed, Mar 18
Virgin Atlantic Logo
7:30 am - 10:30 amONT-LHR
19h 00m1 stop
Virgin Atlantic Logo
12:20 pm - 10:34 pmLHR-ONT
17h 14m1 stop
$599Virgin Atlantic
Find Deal
Wed, Jan 21 - Thu, Jan 29
Iberia Logo
10:58 am - 8:35 amONT-LHR
13h 37m1 stop
Iberia Logo
3:00 pm - 10:48 pmLHR-ONT
15h 48m1 stop
$603Iberia
Find Deal
Sun, Jan 11 - Tue, Jan 27
Iberia Logo
10:58 am - 8:35 amONT-LHR
13h 37m1 stop
Iberia Logo
3:00 pm - 10:48 pmLHR-ONT
15h 48m1 stop
$604Iberia
Find Deal
Wed, Jan 28 - Sun, Feb 1
Delta Logo
6:00 am - 6:20 amONT-LHR
16h 20m2 stops
Delta Logo
8:40 am - 9:05 pmLHR-ONT
20h 25m2 stops
$605Delta
Find Deal
Tue, Jan 6 - Tue, Jan 13
Delta Logo
10:30 pm - 7:05 amONT-LHR
24h 35m2 stops
Delta Logo
2:30 pm - 10:51 pmLHR-ONT
16h 21m1 stop
$607Delta
Find Deal
Wed, Jan 28 - Sun, Feb 1
American Airlines Logo
6:00 am - 9:00 amONT-LGW
19h 00m2 stops
American Airlines Logo
11:20 am - 12:03 pmLGW-ONT
56h 43m2 stops
$805American Airlines
Find Deal
Wed, Jan 28 - Sun, Feb 1
American Airlines Logo
6:00 am - 9:00 amONT-LGW
19h 00m2 stops
American Airlines Logo
11:20 am - 6:45 pmLGW-ONT
39h 25m2 stops
$830American Airlines
Find Deal
Booking Insights

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.

How much is a round-trip flight from Ontario to London?

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 departing in January.

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 October, where tickets cost $679 (return) on average. On the other hand, the most expensive months are June and July, where the average cost of round-trip tickets is $1,064 and $959 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 1 week before departure. For the absolute cheapest price, our data suggests you should book 15 weeks before departure.

Good to know

Low seasonJanuary
Cheapest flight$334
Best time to beat the crowds with an average 13% drop in price.
Most popular time to fly and prices are also 3% lower on average.
Flight from Ontario to London Heathrow 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 $334 for a one-way ticket and $589 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 $752 and an overall rating of 7.9, Delta is the most popular choice. United Airlines is also a great choice for the route, with an average price of $851 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.

Reviews of the 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.
7.9
DeltaOverall score based on 8004 reviews
8.1Boarding
7.3Food
7.9Comfort
7.9Entertainment
8.5Crew
Airline reviews

No lunch on a x-country flight scheduled for 10:50 am departure, arrived 5+ hrs later. That requires a black box label before you pay for the tickets. Worst, when I checked in online, it's specifically said that lunch was served on his flight for economy Plus passengers.

8.0 ExcellentDeborah, Nov 2025LAX - RDU
Read more Delta reviews

No lunch on a x-country flight scheduled for 10:50 am departure, arrived 5+ hrs later. That requires a black box label before you pay for the tickets. Worst, when I checked in online, it's specifically said that lunch was served on his flight for economy Plus passengers.

Our flight from SFO to MSP was right on time on 11/15/2025. No delays. As we approached MSP at about 8 pm, we circled in the air until 8:40 pm so I don't call that efficient for MSP. I think the captain should announce the delay and why. (as if we all don't know that we are just circling around the area, slowing down, speeding up, slowing down.) Thank you. Marilyn Fischer

Plenty of leg room, temperature was great and staff was excellent. Would do it more often.

Staff were friendly and happy. Delta could make sure passengers that don't have the app know of changes. Without Kayak I would not have known about the change of gate or the delay. Kayak was faster to notify me.

The flight used a B767 with a very old interior from before 2014. The entertainment system did not work at all during the flight despite attempts to reset the system. It was like they flew this route just to be competitive.

Delayed flight (1hour) plus a long layover after an overnight flight with no backup plane available.

Passengers need to check in big baggage instead of bringing on the plane. That cause inconvenience for everyone. Otherwise flight was good.

Flight delayed for two and half hours and then canceled altogether due to mechanical issues. No mechanic onsite to fix so had to send one from LAX.

Great. Very smooth. Plenty of information. However, wish they would give out a menu in advance of making a dinner choice like other international airlines. The flight attendant says chicken or pasta and there are details about ingredients or spices requiring the passenger to ask which requires the flight attendant to answer many times. So easy to solve this problem. P

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.

from SFO-> FRA flight, AVML meal was significantly less compared to regular meal, especially no Desert, no Bread, no sides.

This was an older airplane. The cabin was constantly warm to hot throughout the 10 hour flight and there were no vents to personalize air flow. Also since it was an older plane, the material and comfort of the chairs were very uncomfortable. I left my flight with major soreness on my tailbone.

Older aircraft, no meal, only food was for purchase. Not impressed United.

Not pleasant trip cross country when the entertainment and WiFi system not working. No entertainment for entirety of route. Staff was rather nonchalant in that they dismissed the problem due to age of plane. It would have been nice to know this up front so I could have come prepared to read or download movies before boarding Coincidentally or not, there was a similar issue with the entertainment system on my previous flight I took on my fist leg of the trip. There are no seat TVs, so you must rely on the app when it works. United can do better. Also, what use it it to pay for boarding group 2 when half of the passengers are in the same line as you?

My experience on this United Airlines flight was highly uncomfortable, primarily due to two issues: Cabin Temperature: The temperature on the Boeing 737 MAX 8 was unacceptably high, feeling consistently around 80 degrees throughout the flight. This made sleeping impossible and significantly detracted from the experience. Seating Arrangement: Being stuck in a middle seat for a six-and-a-half-hour overnight flight compounded the discomfort. Moving forward, I will always purchase a seat assignment to avoid this situation.

Premium Plus is a really good idea for longer flights

Same as last comment. Food sucks. Quality. Not surprising most people have no clue about nourishment Clearly

The flight attendants were great, I joked with one I can’t remember her name, a blond, really sweet. I thought it was run well very professional. This was great i survived Spirit, I know for which I speak.

We were in business class. the angled seats in that class do not have a real window view & the placement of the controls are bad. But we knew that. But the food options were mediocre. The taste was fine, but the size was for a child. It’s just really feels like United is skimping on everything. Even when we were in the Polaris lounge they did not have diet sodas. They said they were out no Coke zero no Diet Coke, etc. I do not think the portion of nuts they serve on the plane could get any smaller. Really a minimal service and offer for what you’re paying for in business.

I was in first class. The outlets at my seat did not work. The plane was shabby and run down. I had prepurchsed a day subscription for internet that was not redeemable. I had to repurchase the internet for my flight and then it didn’t work anyway. Quite disappointed in what was supposed to be the launch of a great vacation.

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.

Lost luggage stuck no clothes and no word after 2 days leaving on cruise no stuff or clothes

Don’t know they cancelled the flight day before I was to leave. They sent a email at 9:00 pm at night saying they cancelled. That is the smooth way to say we don’t want your business! I think they didn’t have enough people booking so they cancelled the flight! It’s all about the money anymore there is no honesty in business.

The flight was canceled 3 hours after original take off time

Pathetic check in experience at JFK. Everything is self check in. Not enough staff present to help with when the check in process or the kiosk gets stuck. Staff present not welcoming or pleasant at all. On the other hand the NY based flight crew was great. Courteous and friendly throughout the flight. Special meals leave a lot to be desired. Kids meals should be made available when kids are flying and same goes for special kids meals too.

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.

The staff was very nice and helpful. Some of the best crew I have met.

Suddenly, I don't find my flight back on the app Help Ticket 0757345716866 Hoeflich Flight back Sunday ib5333 Ib2629 Ib4268

Was all good.l including a sofdrink. AA improved significantly. There was no entertainment.

I've taken British Airways before and it has been great. On this trip to Spain and Portugal we had two BA flights. On both flights we were taken by bus from the terminal out to the plane on the tarmac. There were many older folks on these flights, and to ask people in their 70s to lug their carry-on and personal items up the long mobile staircase to the plane entrance, is very disturbing. I won't be taking British Airways in the future. Many people on these flights were very unhappy.

The food on the flight was of marginal quality. Small bits of chicken, instant mashed potatoes and some carrots. The rolls were very dry, nearly inedible. The seats were quite small and didn’t allow for any shifting of position during the flight. There was limited leg room.0

The seats are so small that you can barely move at all. Don't try to eat with utensils in your seat either - you will elbow your neighbor in the face. Miserably small and I swear they are shrinking every time I fly. Food was meh (per usual), but at least there is free alcohol on an overseas flight. Doesn't make up for sitting in a torture chamber while hurtling through the air with hundreds of fussy people, but it's something. Entertainment options (movies, shows) are okay, nothing special, but at least there are screens, because most of the seats in these large planes do not have adjustable lighting - or air control - that you can get to, it's too high to reach - which makes reading impossible. Zero stars, AA.

Terrible customer service. I booked business class and the counter agent didn’t bother asking me about any choice or preferred seat, basically assigned me that last seat and couldn’t even answer if it was a business class seat. Also iberia lost my suitcase on my flight from JFK to MAD with the layover in BCN. Useless customer service at the counter. Thank goodness I happened to check the baggage claim area of the next flight in…there it was.

Disaster. Downgraded. Zero apology. No effort or coordination between gate and crew. Awful seat blocked by door emergency slide box. Iberia is a mess. App never works. Avoid this airline.

We departed late but made up most of the time in flight. Our ticket was pure economy, so it wasn’t anything fancy; however, I heard that we arrived in Madrid at the exact same time that First Class passengers arrived! Overall, our experience was similar to what we had on other American Airlines transatlantic flights - good value at a reasonable price. We were even able to get our carry-on baggage onto the plane without needing to gate check it.

The crew were friendly and helpful. Iberia lost our luggage on arrival, Friday and we didn't get it until Sunday at 10:00 p.m. local Malaga time. I also paid $382.80 for seat assignments but two out out of the four were not together. Iberia mentioned that it was because the plane was delayed in Madrid before our flight began in LAX. They should compensate us half of my payment.

Smooth trip no turbulence which is always a bonus for me lol! In cattle class so an element of being a bit squished (but not as bad as other shorter haul airlines) smaller plane than the one we flew out on and entertainment system wasn’t as modern but still definitely passed the time. Lovely crew x

Flying on the Boeing 787 from Seattle to London was everything that I expected. Every thing was great.

Seat pitch is not enough to eat comfortably. When seat in front is reclined, your screen comes closer to your face. Ryanair seats are actually more comfortable.

The leg from Portland to Heathrow was great for a business class ticket. The BA leg from Heathrow to Lisbon was terrible. Basically coach seating with an empty seat between you and next passenger. Absolutely no leg room. Should not have been charged for business class and it was a 3 hour flight.

The flat beds. Other than that, the place was not clean.

Moved me away from my family and refused to fix it.

I have always been pleased with their service. Would not change a thing

Seating and food was the worst we have experienced in 35 years of traveling for both personal and busines .

Economy seats felt more cramped than other flights we have taken.7 hr, painful sitting hours 6 and 7. Web site difficult to deal with. Originally put in for 1 special meal due to type 2. Meal was awful. Tried to change selection to standard for return flight, on app and website, unable to complete that action.

I was sleeping during dinner service, no one bothered to offer meal later, I remained hungry….until I got a morning sandwich!

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

Information on your arrival and departure airports