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Heathrow

$451+ Cheap flights from Ontario (ONT) to Heathrow (LHR)

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 4/21. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LHR
Apr 21 — Apr 281
Tue 4/21
Tue 4/28
1 adult, Economy
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Cheap flight deals from Ontario to Heathrow

Cheapest flights from Ontario to Heathrow
Explore the most affordable flight options available from Ontario to Heathrow. Find the lowest fares from popular airlines and budget airlines, with prices last updated on March 22, 2026.

This lol.travel 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 lol.travel is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/510:56 am
ONT
-
LHR
1 stop13h 09m
British Airways
Tue 4/2110:05 am
LHR
-
ONT
1 stop14h 17m
British Airways
Deal found 3/17$804
This Cheapflightsfares 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/110:56 am
ONT
-
LHR
1 stop12h 59m
British Airways
Thu 4/910:05 am
LHR
-
ONT
1 stop14h 17m
British Airways
Deal found 3/17$808
This Trip.com deal was found by Cheapflights users on 3/18. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/11:29 pm
ONT
-
LHR
1 stop12h 31m
Virgin Atlantic
Sat 7/410:55 am
LHR
-
ONT
1 stop13h 19m
Virgin Atlantic
Deal found 3/18$819
This British Airways 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 British Airways is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/237:20 am
ONT
-
LHR
1 stop17h 40m
British Airways
Tue 9/812:00 pm
LHR
-
ONT
1 stop17h 28m
British Airways
Deal found 3/17$820
This FlightHub 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/162:22 pm
ONT
-
LHR
1 stop13h 48m
British Airways
Tue 8/252:25 pm
LHR
-
ONT
1 stop14h 43m
British Airways
Deal found 3/17$838
This Iberia deal was found by Cheapflights users on 3/20. 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 4/77:30 am
ONT
-
LHR
1 stop16h 35m
Iberia
Fri 4/1710:50 am
LHR
-
ONT
2 stops20h 56m
Iberia
Deal found 3/20$839
This Delta deal was found by Cheapflights users on 3/18. 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
-
LHR
1 stop13h 50m
Delta
Tue 5/56:30 am
LHR
-
ONT
2 stops18h 45m
Delta
Deal found 3/18$841
This Delta deal was found by Cheapflights users on 3/18. 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 5/611:53 am
ONT
-
LHR
1 stop16h 17m
Delta
Wed 5/136:30 am
LHR
-
ONT
2 stops18h 40m
Delta
Deal found 3/18$842

Find flight deals from Ontario to Heathrow

Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to Heathrow (LHR). 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 22, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$808
(Cheapflightsfares)

One-way from

$451
(Cheapflightsfares)

Popular in

June

Cheapest in

November

Average price

$800
Provider with most accurate pricing for Ontario-London Heathrow flight deals.
Search Deals
Provider most trusted by Cheapflights users for Ontario-London Heathrow flights.
Search Deals
From Ontario to London Heathrow
Search Deals
One-way flight from Ontario to London Heathrow
Search Deals
Highest demand for flights based on searches. 23% potential increase in price ($263 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease ($48 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 Heathrow 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 22, 2026.
Use the filters below to find and compare flights from Ontario to London Heathrow Airport that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 4/5

1:34 pm-12:35 pm

1 stop15h 01m

London Heathrow

Tue 4/21

2:50 pm-8:36 pm

1 stop13h 46m

$867

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 8/25

7:00 am-9:00 am

1 stop18h 00m

London Heathrow

Mon 9/7

10:00 am-9:59 pm

1 stop19h 59m

$916

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sat 5/2

10:59 am-8:35 am

1 stop13h 36m

London Heathrow

Fri 5/15

10:05 am-4:22 pm

1 stop14h 17m

$922

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sat 8/8

1:18 pm-9:40 am

1 stop12h 22m

London Heathrow

Sun 8/16

1:40 pm-9:59 pm

1 stop16h 19m

$1,121

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Thu 5/21

5:50 pm-3:35 pm

1 stop13h 45m

London Heathrow

Wed 6/3

11:40 am-10:32 pm

1 stop18h 52m

$1,203
Quickest round-trip

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 7/1

1:50 pm-11:10 am

1 stop13h 20m

London Heathrow

Thu 7/16

2:50 pm-8:42 pm

1 stop13h 52m

$1,252

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sat 4/4

2:39 pm-12:10 pm

1 stop13h 31m

London Heathrow

Tue 4/7

12:55 pm-8:54 pm

1 stop15h 59m

$1,262

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 7/27

5:38 pm-3:05 pm

1 stop13h 27m

London Heathrow

Thu 8/6

5:00 pm-11:11 pm

1 stop14h 11m

$1,265

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 7/6

1:50 pm-11:10 am

1 stop13h 20m

London Heathrow

Mon 7/13

2:50 pm-8:42 pm

1 stop13h 52m

$1,270

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 6/1

10:00 pm-8:45 pm

1 stop14h 45m

London Heathrow

Mon 6/8

11:55 am-8:45 pm

1 stop16h 50m

$1,273

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/20

Showing 1-10 of 21 resultsSorted by cheapest first
1
2
3

Compare providers for flights from Ontario to Heathrow

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 Heathrow in March.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
CheapflightsfaresPrice Accuracy2 starsTrust Score*2 stars
Thrive TravelPrice Accuracy3 starsTrust Score*2 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 Heathrow Airport flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ontario-London Heathrow Airport flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ontario-London Heathrow Airport flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Ontario-London Heathrow Airport 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 Heathrow Airport 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 Heathrow

Have a flexible travel schedule? Discover the best time to fly to Heathrow 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 Heathrow Airport

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

Currently, December is the cheapest month in which you can book a flight from Ontario to London Heathrow Airport (average of $469). Flying from Ontario to London Heathrow Airport in June is currently the most expensive (average of $699). 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.

Reviews of airlines servicing Heathrow

Get insights into the airlines that provide service to Heathrow. 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 Heathrow. Reviews last updated March 22, 2026.
Read through reviews of airlines operating flights from Ontario to London Heathrow Airport, such as Delta,KLM, andUnited Airlines. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Delta
7.9
Good
8,314 reviews

Crew

8.5

Boarding

8.1

Comfort

7.9

Overall

7.9

Entertainment

7.8

Food

7.2

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
8,314 reviews
Delta
7.9
Good
8,314 reviews

Crew

8.5

Boarding

8.1

Comfort

7.9

Overall

7.9

Entertainment

7.8

Food

7.2

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.
KLM
7.8
Good
1,477 reviews
Delta
7.9
Good
8,314 reviews

Crew

8.5

Boarding

8.1

Comfort

7.9

Overall

7.9

Entertainment

7.8

Food

7.2

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
9,455 reviews
Delta
7.9
Good
8,314 reviews

Crew

8.5

Boarding

8.1

Comfort

7.9

Overall

7.9

Entertainment

7.8

Food

7.2

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
11,486 reviews
Delta
7.9
Good
8,314 reviews

Crew

8.5

Boarding

8.1

Comfort

7.9

Overall

7.9

Entertainment

7.8

Food

7.2

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
7,807 reviews
Delta
7.9
Good
8,314 reviews

Crew

8.5

Boarding

8.1

Comfort

7.9

Overall

7.9

Entertainment

7.8

Food

7.2

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 Heathrow. 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 Heathrow?

    If you book a flight to London Heathrow from Ontario, you will be flying from Ontario, which is the city’s only airport. Ontario (ONT) is located 3.1 mi from the center of Ontario. There are 0 flights from Ontario to London Heathrow per day from 5 different airlines.

  • How long is the flight from Ontario to London Heathrow Airport?

    United Airlines and British Airways can get you from Ontario to London Heathrow Airport in just under 13h 36m. Your travel time can differ by up to 1h 25m. The distance between Ontario and London Heathrow Airport is about 5407 mi. Both multi-stop and nonstop flights can be found to your destination and back.

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

    According to our current data, Delta ($570), KLM ($580), and American Airlines ($624) offers the cheapest pricing from Ontario to London Heathrow Airport. Delta is 33% cheaper than the average price of flights available within the next 90 days to this destination.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Ontario to Heathrow 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 Heathrow Airport?

    Currently, December is the cheapest month in which you can book a flight from Ontario to London Heathrow Airport (average of $469). Flying from Ontario to London Heathrow Airport in June is currently the most expensive (average of $699). 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 Heathrow Airport?

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

Browse thousands of different options on Cheapflights for your next trip

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Top 5 airlines flying from Ontario to Heathrow

Discover the top 5 airlines that operate flights from Ontario to Heathrow. 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 22, 2026.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$570Average$672FlexibilityNo cancel feeOn-timeN/A
KLMCheapest$580Average$672FlexibilityNo cancel feeOn-time75%
American AirlinesCheapest$624Average$687FlexibilityNo cancel feeOn-time71%
British AirwaysCheapest$624Average$756FlexibilityNo cancel feeOn-time70%
United AirlinesCheapest$662Average$941FlexibilityNo cancel feeOn-time69%

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