London

$319+ Cheap flights from Ontario (ONT) to London (LON)

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 10/11. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LON
Jul 4 — Jul 111
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Find cheap flights from Ontario to London with Cheapflights

1. Tell us where you want to go

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Cheap flight deals from Ontario to London

Cheapest flights from Ontario to London
Explore the most affordable flight options available from Ontario to London. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 4, 2026.

This Expedia deal was found by Cheapflights users on 6/3. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/271:05 pm
ONT
-
LHR
1 stop18h 00m
Multiple Airlines
Wed 10/710:50 am
LHR
-
ONT
2 stops20h 16m
Multiple Airlines
Deal found 6/3$826
This Expedia deal was found by Cheapflights users on 6/1. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/271:05 pm
ONT
-
LHR
1 stop18h 00m
British Airways
Wed 10/78:55 am
LHR
-
ONT
1 stop20h 13m
British Airways
Deal found 6/1$828
This Priceline deal was found by Cheapflights users on 6/3. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/712:00 pm
ONT
-
LHR
1 stop16h 20m
Multiple Airlines
Sun 12/132:20 pm
LHR
-
ONT
1 stop15h 40m
Multiple Airlines
Deal found 6/3$829
This Orbitz deal was found by Cheapflights users on 6/2. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/1110:47 am
ONT
-
LHR
1 stop17h 28m
Multiple Airlines
Wed 11/187:40 pm
LHR
-
ONT
2 stops34h 43m
Multiple Airlines
Deal found 6/2$831
This Expedia deal was found by Cheapflights users on 6/3. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/36:00 am
ONT
-
LHR
2 stops17h 10m
Multiple Airlines
Tue 11/1011:45 am
LHR
-
ONT
1 stop17h 26m
Multiple Airlines
Deal found 6/3$832
This Orbitz deal was found by Cheapflights users on 6/4. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/16:00 am
ONT
-
LHR
2 stops16h 35m
Multiple Airlines
Sat 9/128:55 am
LHR
-
ONT
1 stop21h 42m
Multiple Airlines
Deal found 6/4$837
This The Travel House deal was found by Cheapflights users on 6/1. 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 The Travel House is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/26:02 am
ONT
-
LHR
1 stop25h 03m
Alaska Airlines
Wed 9/165:00 pm
LHR
-
ONT
1 stop29h 16m
Alaska Airlines
Deal found 6/1$841
This Orbitz deal was found by Cheapflights users on 6/1. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/47:13 pm
ONT
-
LHR
2 stops51h 17m
Multiple Airlines
Mon 9/144:25 pm
LHR
-
ONT
1 stop25h 04m
Multiple Airlines
Deal found 6/1$842
This Priceline deal was found by Cheapflights users on 6/3. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/154:47 pm
ONT
-
LHR
1 stop12h 28m
Multiple Airlines
Fri 11/272:45 pm
LHR
-
ONT
1 stop15h 54m
Multiple Airlines
Deal found 6/3$845
This Orbitz deal was found by Cheapflights users on 6/3. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/52:43 pm
ONT
-
LHR
1 stop31h 37m
Iberia
Sat 10/38:00 pm
LHR
-
ONT
2 stops35h 36m
Iberia
Deal found 6/3$848
This Delta deal was found by Cheapflights users on 6/3. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/237:05 am
ONT
-
LGW
2 stops18h 20m
Delta
Mon 9/2810:25 am
LGW
-
ONT
2 stops20h 15m
Delta
Deal found 6/3$907
This Delta deal was found by Cheapflights users on 5/31. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/57:05 am
ONT
-
LGW
2 stops18h 15m
Delta
Thu 9/1010:25 am
LGW
-
ONT
2 stops20h 15m
Delta
Deal found 5/31$928

Find flight deals from Ontario to London

Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to London (LON). 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 June 4, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$826
(Expedia)

One-way from

$319
(Cheapflightsfares)

Popular in

June

Cheapest in

March

Average price

$1,433
Provider with most accurate pricing for Ontario-London (LON) flight deals.
Provider most trusted by Cheapflights users for Ontario-London (LON) flights.
From Ontario to London (LON)
One-way flight from Ontario to London (LON)
Highest demand for flights based on searches. 31% potential increase in price ($390 potential increase over avg. RT price).
Cheapest flight prices on average. 6% potential price decrease ($54 potential savings vs. average RT price).
Average for round-trip flights in June 2026

Cheapflights Fare Finder

 
Customize your flight search to find flights from Ontario to London 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 June 4, 2026.
Use the filters below to find and compare flights from Ontario to London that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Wed 9/23

7:05 am-9:25 am

2 stops18h 20m

London Gatwick

Mon 9/28

10:25 am-10:40 pm

2 stops20h 15m

$907

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 8/3

12:00 pm-1:15 pm

1 stop17h 15m

London Heathrow

Thu 8/20

11:15 am-9:52 pm

1 stop18h 37m

$923

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 8/5

12:04 pm-3:05 pm

1 stop19h 01m

London Heathrow

Fri 8/21

5:00 pm-11:24 pm

1 stop14h 24m

$923

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 9/20

12:12 pm-3:05 pm

1 stop18h 53m

London Heathrow

Sun 9/27

5:00 pm-11:24 pm

1 stop14h 24m

$927

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Sat 9/5

7:05 am-9:20 am

2 stops18h 15m

London Gatwick

Thu 9/10

10:25 am-10:40 pm

2 stops20h 15m

$928
Quickest round-trip

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 7/27

1:18 pm-9:40 am

1 stop12h 22m

London Heathrow

Wed 8/12

2:50 pm-8:53 pm

1 stop14h 03m

$967

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Fri 9/18

1:18 pm-12:25 pm

1 stop15h 07m

London Heathrow

Sun 10/4

1:40 pm-9:58 pm

1 stop16h 18m

$995

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Wed 11/11

7:00 am-9:00 am

2 stops18h 00m

London Gatwick

Tue 12/1

10:00 am-10:14 pm

2 stops20h 14m

$998

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sat 8/8

9:20 pm-3:05 pm

1 stop33h 45m

London Heathrow

Sun 8/23

5:00 pm-11:04 am

1 stop26h 04m

$1,036

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Thu 11/19

12:00 pm-12:20 pm

1 stop16h 20m

London Heathrow

Sun 11/29

2:45 pm-11:09 am

1 stop28h 24m

$1,078

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/3

Showing 1-10 of 58 resultsSorted by cheapest first
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6

Compare providers for flights from Ontario to London

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Ontario to London in June.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
OvagoPrice Accuracy3 starsTrust Score*3 stars
AranGrantPrice Accuracy3 starsTrust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Ontario-London flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ontario-London flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ontario-London flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Ontario-London 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 Ontario-London 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 Ontario to London

Have a flexible travel schedule? Discover the best time to fly to London from Ontario 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 Ontario to London

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

Currently, September is the cheapest month in which you can book a flight from Ontario to London (average of $251). Flying from Ontario to London in June is currently the most expensive (average of $1,105). 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 Ontario to London?

Reviews of airlines servicing London

Get insights into the airlines that provide service to London. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to London. Reviews last updated June 4, 2026.
Get a feel of what it's like to fly with Delta,United Airlines, andBritish Airways from Ontario to London by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.

Crew

8.5

Entertainment

7.8

Comfort

7.8

Boarding

8.1

Food

7.2

Overall

7.9

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.

Crew

8.5

Entertainment

7.8

Comfort

7.8

Boarding

8.1

Food

7.2

Overall

7.9

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.

Crew

8.5

Entertainment

7.8

Comfort

7.8

Boarding

8.1

Food

7.2

Overall

7.9

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.

Crew

8.5

Entertainment

7.8

Comfort

7.8

Boarding

8.1

Food

7.2

Overall

7.9

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.

Related info for your journey

Find useful and relevant information for your journey from Ontario to London. 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 from for flights from Ontario to London?

    Most people fly from Ontario (ONT) if they book a flight from Ontario to London. On average, Ontario has 0 outbound flights to London per day from 5 airlines. Ontario is conveniently located just 3.1 mi from Ontario’s city center.

  • How long is the flight from Ontario to London?

    Delta, KLM, and Alaska Airlines can get you from Ontario to London in just under 17h 15m. Your travel time can differ by up to 1h 46m. Airlines will cover a distance of 5407 mi. This flight may include one or multiple stops.

  • What are the cheapest airlines flying from Ontario to London round-trip?

    Flying on Delta is currently your cheapest option to London, with prices starting at $570. Additional round-trip tickets that might be worth considering are offered by KLM and American Airlines, with the lowest prices starting at $580 and $620, respectively. You may be able to fly from Ontario to London for 32% less than the average price by searching for these airlines.

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

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Ontario to London 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 Ontario to London?

    Currently, September is the cheapest month in which you can book a flight from Ontario to London (average of $251). Flying from Ontario to London in June is currently the most expensive (average of $1,105). 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

Traveling to a place near London?

Book flights to London if you plan to visit one of these locations
Ilford
Dorking
Hounslow
Winchester
Croydon
Gatwick
Southend-on-Sea
Harrow
Eastleigh
Dartford
Dover
Orpington
Watford
Chipping Norton
Hayes
Kingston upon Thames
Eastbourne
Slough
Stansted
Sutton

Browse thousands of different options on Cheapflights for your next trip

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Top 5 airlines flying from Ontario to London

Discover the top 5 airlines that operate flights from Ontario to London. 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 June 4, 2026.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$570Average$672FlexibilityNo cancel feeOn-timeN/A
KLMCheapest$580Average$672FlexibilityNo cancel feeOn-time75%
American AirlinesCheapest$620Average$650FlexibilityNo cancel feeOn-time71%
British AirwaysCheapest$624Average$871FlexibilityNo cancel feeOn-time70%
United AirlinesCheapest$665Average$972FlexibilityNo cancel feeOn-time69%

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