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$362+ 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 7/16. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LON
Apr 12 — Apr 191
Sun 4/12
Sun 4/19
1 adult, Economy
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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 March 13, 2026.

This Cheapflightsfares deal was found by Cheapflights users on 3/10. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/2710:59 am
ONT
-
LHR
1 stop13h 06m
British Airways
Wed 5/610:05 am
LHR
-
ONT
1 stop14h 17m
British Airways
Deal found 3/10$733
This Iberia deal was found by Cheapflights users on 3/7. 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 Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/810:59 am
ONT
-
LHR
1 stop17h 11m
Iberia
Fri 4/1711:30 am
LHR
-
ONT
2 stops20h 16m
Iberia
Deal found 3/7$739
This American Airlines deal was found by Cheapflights users on 3/9. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/66:00 am
ONT
-
LGW
2 stops18h 40m
American Airlines
Wed 5/132:30 pm
LGW
-
ONT
2 stops27h 39m
American Airlines
Deal found 3/9$739
This Iberia deal was found by Cheapflights users on 3/10. 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 Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/57:00 am
ONT
-
LHR
1 stop17h 05m
Iberia
Tue 4/216:10 am
LHR
-
ONT
2 stops22h 44m
Iberia
Deal found 3/10$741
This Iberia deal was found by Cheapflights users on 3/9. 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 Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/142:08 pm
ONT
-
LHR
1 stop16h 17m
Iberia
Tue 4/216:10 am
LHR
-
ONT
2 stops22h 44m
Iberia
Deal found 3/9$743
This Delta deal was found by Cheapflights users on 3/9. 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 4/1511:53 am
ONT
-
LHR
1 stop16h 17m
Delta
Tue 5/511:45 am
LHR
-
ONT
2 stops18h 52m
Delta
Deal found 3/9$744
This Air Canada deal was found by Cheapflights users on 3/8. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/85:10 am
ONT
-
LHR
2 stops20h 50m
Air Canada
Tue 4/213:05 pm
LHR
-
ONT
2 stops37h 31m
Air Canada
Deal found 3/8$752
This United Airlines deal was found by Cheapflights users on 3/8. 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 4/221:27 pm
ONT
-
LHR
1 stop13h 43m
United Airlines
Wed 4/299:30 am
LHR
-
ONT
2 stops19h 06m
United Airlines
Deal found 3/8$755
This Delta deal was found by Cheapflights users on 3/9. 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 4/152:20 pm
ONT
-
LGW
2 stops17h 40m
Delta
Tue 5/510:35 am
LGW
-
ONT
2 stops18h 25m
Delta
Deal found 3/9$755
This KLM deal was found by Cheapflights users on 3/8. 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 KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 3/2412:57 pm
ONT
-
LHR
1 stop13h 03m
Multiple Airlines
Tue 3/3110:55 am
LHR
-
ONT
1 stop13h 33m
Multiple Airlines
Deal found 3/8$756
This Air Canada deal was found by Cheapflights users on 3/8. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/115:10 am
ONT
-
LHR
2 stops41h 25m
Air Canada
Tue 4/213:05 pm
LHR
-
ONT
2 stops37h 31m
Air Canada
Deal found 3/8$757
This United Airlines deal was found by Cheapflights users on 3/8. 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.
Sat 5/26:59 pm
ONT
-
LHR
2 stops27h 46m
United Airlines
Wed 5/139:30 am
LHR
-
ONT
2 stops20h 28m
United Airlines
Deal found 3/8$759

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 March 13, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$733
(Cheapflightsfares)

One-way from

$362
(Kiwi.com)

Popular in

July

Cheapest in

March

Average price

$652
Provider with most accurate pricing for Ontario-London (LON) flight deals.
Search Deals
Provider most trusted by Cheapflights users for Ontario-London (LON) flights.
Search Deals
From Ontario to London (LON)
Search Deals
One-way flight from Ontario to London (LON)
Search Deals
Highest demand for flights based on searches. 23% potential increase in price ($230 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease ($32 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 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 March 13, 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

Mon 4/27

2:20 pm-4:00 pm

2 stops17h 40m

London Gatwick

Wed 5/6

10:25 am-10:37 pm

2 stops20h 12m

$755

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Wed 4/15

2:20 pm-4:00 pm

2 stops17h 40m

London Gatwick

Tue 5/5

10:35 am-10:37 pm

2 stops20h 02m

$755

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Tue 4/28

2:20 pm-4:00 pm

2 stops17h 40m

London Gatwick

Thu 5/7

10:25 am-10:34 pm

2 stops20h 09m

$755

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 4/20

1:34 pm-12:25 pm

1 stop14h 51m

London Heathrow

Wed 5/6

2:50 pm-8:36 pm

1 stop13h 46m

$812

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 3/24

1:40 pm-12:00 pm

1 stop15h 20m

London Heathrow

Fri 4/3

2:50 pm-8:36 pm

1 stop13h 46m

$823

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 5/13

5:50 pm-3:35 pm

1 stop13h 45m

London Heathrow

Fri 5/22

11:15 am-6:36 pm

1 stop15h 21m

$823

OntarioLondon

ONT - LCY

ONTLCY

Ontario

Wed 4/1

1:20 pm-4:40 pm

2 stops19h 20m

London City

Thu 4/16

9:20 am-10:37 pm

2 stops21h 17m

$828

OntarioLondon

ONT - LCY

ONTLCY

Ontario

Wed 4/1

5:09 pm-4:40 pm

2 stops15h 31m

London City

Thu 4/9

10:00 am-10:34 pm

2 stops20h 34m

$829

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 8/26

7:00 am-3:35 pm

1 stop24h 35m

London Heathrow

Sat 9/12

6:15 am-10:40 pm

2 stops24h 25m

$851

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Fri 5/1

12:19 pm-10:50 am

1 stop14h 31m

London Heathrow

Mon 5/11

12:55 pm-11:46 pm

1 stop18h 51m

$873

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/8

Showing 1-10 of 60 resultsSorted by cheapest first
1
2
3
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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 March.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
OvagoPrice Accuracy2 starsTrust Score*3 stars
AranGrantPrice Accuracy2 starsTrust Score*2 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, October is the cheapest month in which you can book a flight from Ontario to London (average of $222). Flying from Ontario to London in June is currently the most expensive (average of $564). 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 March 13, 2026.
Get a feel of what it's like to fly with Delta,United Airlines, andAmerican Airlines 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.
Delta
7.9
Good
8,283 reviews

Boarding

8.1

Crew

8.5

Entertainment

7.8

Comfort

7.9

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.
Delta
7.9
Good
8,283 reviews
Delta
7.9
Good
8,283 reviews

Boarding

8.1

Crew

8.5

Entertainment

7.8

Comfort

7.9

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.
United Airlines
7.4
Good
9,418 reviews
Delta
7.9
Good
8,283 reviews

Boarding

8.1

Crew

8.5

Entertainment

7.8

Comfort

7.9

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.
American Airlines
7.1
Good
11,444 reviews
Delta
7.9
Good
8,283 reviews

Boarding

8.1

Crew

8.5

Entertainment

7.8

Comfort

7.9

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.
British Airways
6.7
Okay
7,784 reviews
Delta
7.9
Good
8,283 reviews

Boarding

8.1

Crew

8.5

Entertainment

7.8

Comfort

7.9

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, United Airlines, and British Airways can get you from Ontario to London in just under 14h 31m. Your travel time can differ by up to 3h 09m. 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 $624, respectively. You may be able to fly from Ontario to London for 26% less than the average price by searching for these airlines.

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

    The most popular flight routes from Ontario to London are Ontario - London Heathrow, Ontario - London Gatwick and Ontario - London City.

  • 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, October is the cheapest month in which you can book a flight from Ontario to London (average of $222). Flying from Ontario to London in June is currently the most expensive (average of $564). 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
Hounslow
Croydon
Gatwick
Southend-on-Sea
Harrow
Eastleigh
Dartford
Dover
Winchester
Orpington
Watford
Borehamwood
Aylesbury
Chipping Norton
Hayes
Kingston upon Thames
Eastbourne
Sutton
Slough

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 March 13, 2026.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$570Average$671FlexibilityNo cancel feeOn-timeN/A
KLMCheapest$580Average$653FlexibilityNo cancel feeOn-time75%
American AirlinesCheapest$624Average$687FlexibilityNo cancel feeOn-time71%
British AirwaysCheapest$624Average$763FlexibilityNo cancel feeOn-time70%
United AirlinesCheapest$662Average$941FlexibilityNo cancel feeOn-time69%

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