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$436+ Cheap flights from London (LON) to Ontario (ONT)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 4/29. Fares are subject to change and may not be available on all flights or dates of travel.
LON — ONT
Apr 16 — Apr 231
Thu 4/16
Thu 4/23
1 adult, Economy
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Cheap flight deals from London to Ontario

Cheapest flights from London to Ontario
Explore the most affordable flight options available from London to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on March 17, 2026.

This TravelUp deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure TravelUp is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/103:00 pm
LHR
-
ONT
1 stop15h 23m
British Airways
Sun 11/154:47 pm
ONT
-
LHR
1 stop12h 28m
British Airways
Deal found 3/13$597
This United Airlines deal was found by Cheapflights users on 3/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/157:25 am
LHR
-
ONT
2 stops18h 22m
United Airlines
Wed 4/226:49 pm
ONT
-
LHR
1 stop32h 21m
United Airlines
Deal found 3/16$601
This United Airlines deal was found by Cheapflights users on 3/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/239:30 am
LHR
-
ONT
2 stops20h 29m
United Airlines
Mon 9/286:53 pm
ONT
-
LHR
2 stops18h 42m
United Airlines
Deal found 3/16$602
This United Airlines deal was found by Cheapflights users on 3/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/810:50 am
LHR
-
ONT
2 stops20h 09m
United Airlines
Tue 5/126:00 am
ONT
-
LHR
1 stop24h 10m
United Airlines
Deal found 3/14$603
This United Airlines deal was found by Cheapflights users on 3/17. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/156:55 am
LHR
-
ONT
2 stops18h 52m
United Airlines
Wed 4/2911:05 am
ONT
-
LHR
1 stop16h 05m
United Airlines
Deal found 3/17$604
This United Airlines deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/2410:50 am
LHR
-
ONT
2 stops19h 55m
United Airlines
Fri 5/81:40 pm
ONT
-
LHR
2 stops23h 55m
United Airlines
Deal found 3/13$607
This TravelUp deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure TravelUp is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/710:05 am
LHR
-
ONT
1 stop14h 17m
British Airways
Thu 4/2310:59 am
ONT
-
LHR
1 stop13h 06m
British Airways
Deal found 3/13$608
This TravelUp deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure TravelUp is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/1010:05 am
LHR
-
ONT
1 stop14h 17m
British Airways
Fri 4/2410:59 am
ONT
-
LHR
1 stop13h 06m
British Airways
Deal found 3/13$612
This TravelUp deal was found by Cheapflights users on 3/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure TravelUp is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/1410:05 am
LHR
-
ONT
1 stop14h 17m
British Airways
Tue 4/2110:59 am
ONT
-
LHR
1 stop13h 06m
British Airways
Deal found 3/15$618
This United Airlines deal was found by Cheapflights users on 3/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/1510:50 am
LHR
-
ONT
2 stops19h 55m
United Airlines
Sat 5/95:00 am
ONT
-
LHR
2 stops18h 15m
United Airlines
Deal found 3/16$619
This TravelUp deal was found by Cheapflights users on 3/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure TravelUp is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/1410:05 am
LHR
-
ONT
1 stop14h 17m
British Airways
Fri 4/2410:59 am
ONT
-
LHR
1 stop13h 06m
British Airways
Deal found 3/14$620
This United Airlines deal was found by Cheapflights users on 3/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/179:30 am
LHR
-
ONT
2 stops20h 20m
United Airlines
Sat 5/95:00 am
ONT
-
LHR
2 stops19h 20m
United Airlines
Deal found 3/16$621

Find flight deals from London to Ontario

Discover tips and strategies to find the most affordable flight options for your journey from London (LON) to Ontario (ONT). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated March 17, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$601
(United Airlines)

One-way from

$436
(Kiwi.com)

Popular in

July

Cheapest in

September

Average price

$563
Provider with most accurate pricing for London (LON)-Ontario flight deals.
Search Deals
Provider most trusted by Cheapflights users for London (LON)-Ontario flights.
Search Deals
From London (LON) to Ontario
Search Deals
One-way flight from London (LON) to Ontario
Search Deals
Highest demand for flights based on searches. 7% potential increase in price ($55 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($18 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in March 2026
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from London to Ontario that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated March 17, 2026.
Use the filters below to find and compare flights from London to Ontario that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Sat 5/2

4:15 pm-10:59 pm

1 stop14h 44m

Ontario

Thu 5/7

1:30 pm-11:10 am

1 stop13h 40m

$633

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Mon 4/13

2:50 pm-8:36 pm

1 stop13h 46m

Ontario

Mon 5/4

7:00 am-6:45 am

1 stop15h 45m

$633

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Wed 4/15

2:50 pm-8:36 pm

1 stop13h 46m

Ontario

Mon 4/20

1:34 pm-12:25 pm

1 stop14h 51m

$633

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Fri 5/1

1:00 pm-10:59 pm

1 stop17h 59m

Ontario

Tue 5/5

7:00 am-6:45 am

1 stop15h 45m

$633

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Wed 4/15

10:35 am-5:47 pm

1 stop15h 12m

Ontario

Wed 5/6

1:30 pm-11:10 am

1 stop13h 40m

$639

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Sun 4/19

1:40 pm-9:50 pm

1 stop16h 10m

Ontario

Sat 5/2

7:00 am-8:30 am

1 stop17h 30m

$639
Quickest round-trip

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Tue 9/1

2:50 pm-8:52 pm

1 stop14h 02m

Ontario

Tue 9/15

1:44 pm-11:10 am

1 stop13h 26m

$640

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Tue 3/31

2:50 pm-8:36 pm

1 stop13h 46m

Ontario

Tue 4/7

11:05 am-11:10 am

1 stop16h 05m

$651

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Fri 4/10

2:10 pm-10:31 pm

1 stop16h 21m

Ontario

Fri 5/1

1:30 pm-11:10 am

1 stop13h 40m

$654

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Sat 7/11

7:45 am-9:55 pm

2 stops22h 10m

Ontario

Fri 7/24

5:00 am-5:55 am

2 stops16h 55m

$664

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/16

Showing 1-10 of 60 resultsSorted by cheapest first
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  • Most accurate provider: When it comes to deals on London-Ontario flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on London-Ontario flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from London-Ontario flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on London-Ontario flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for London-Ontario flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from London to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from London with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

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

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

Use this chart to determine the optimal time to book a round-trip flight from London to Ontario. Price data was last updated on March 13, 2026.

Booking 76 days in advance of your planned departure date is, on average, the best time to get cheap flights from London to Ontario. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

What is the cheapest month to book a flight from London to Ontario?

Currently, September is the cheapest month in which you can book a flight from London to Ontario (average of $320). Flying from London to Ontario in July is currently the most expensive (average of $519). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

How much does it cost to fly round-trip from London to Ontario?

Related info for your journey

Find useful and relevant information for your journey from London to Ontario. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly into for flights to Ontario from London?

    Ontario (ONT), located 3.1 mi from the city center, is the airport you fly into when you book flights from London to Ontario. 1 airline have flights to Ontario from London on a regular basis. Booking flights from London to Ontario should not be difficult; the airport handles an average of 0 inbound flights from London per day.

  • How long is the flight from London to Ontario?

    Airlines like United Airlines, British Airways, and Iberia fly from London to Ontario in about 14h 17m. The time it takes to get you to your destination can typically vary by up to 7h 39m. London and Ontario are separated by a distance of 5407 mi. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

  • What is the cheapest airline to fly from London to Ontario round-trip?

    Cheapflights users have booked flights from London to Ontario round-trip from $497. This flight start at 24% lower than the current average price 3 months from now.

  • What are the most popular routes from London to Ontario?

    Most travelers choose London Heathrow - Ontario, London Gatwick - Ontario or London City - Ontario when deciding on the best route from London to Ontario.

  • Can I find deals for flights from London to Ontario that include hotel bookings?

    Yes. In addition to deals on London to Ontario flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from London to Ontario?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from London to Ontario.

  • Can I find deals for business class flights from London to Ontario?

    Yes. Cheapflights offers flight deals from London to Ontario by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from London to Ontario?

    Currently, September is the cheapest month in which you can book a flight from London to Ontario (average of $320). Flying from London to Ontario in July is currently the most expensive (average of $519). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Top airline flying from London to Ontario

Discover the top airline that operate flights from London to Ontario. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated March 17, 2026.
AirlineCheapestAverageFlexibilityOn-time
United AirlinesCheapest$497Average$694FlexibilityNo cancel feeOn-time69%

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