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$448+ 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 9/22. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LHR
May 23 — May 301
Sat 5/23
Sat 5/30
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 April 23, 2026.

This Iberia deal was found by Cheapflights users on 4/18. 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 Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/62:08 pm
ONT
-
LHR
1 stop16h 17m
Iberia
Wed 5/1310:50 am
LHR
-
ONT
2 stops20h 56m
Iberia
Deal found 4/18$892
This KLM deal was found by Cheapflights users on 4/20. 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 KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/232:00 pm
ONT
-
LHR
1 stop17h 35m
KLM
Tue 9/86:30 am
LHR
-
ONT
2 stops17h 44m
KLM
Deal found 4/20$896
This Trip.com deal was found by Cheapflights users on 4/20. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/45:55 pm
ONT
-
LHR
1 stop13h 40m
Virgin Atlantic
Tue 5/1910:55 am
LHR
-
ONT
1 stop13h 22m
Virgin Atlantic
Deal found 4/20$897
This Delta deal was found by Cheapflights users on 4/20. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/236:00 am
ONT
-
LHR
2 stops17h 10m
Delta
Tue 9/88:40 am
LHR
-
ONT
2 stops22h 00m
Delta
Deal found 4/20$901
This Delta deal was found by Cheapflights users on 4/21. 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 9/55:55 pm
ONT
-
LHR
1 stop34h 15m
Delta
Tue 9/156:30 am
LHR
-
ONT
2 stops17h 44m
Delta
Deal found 4/21$902
This lol.travel deal was found by Cheapflights users on 4/18. 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 lol.travel is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 5/310:54 am
ONT
-
LHR
1 stop13h 11m
British Airways
Tue 5/1910:05 am
LHR
-
ONT
1 stop14h 17m
British Airways
Deal found 4/18$904
This Air Canada deal was found by Cheapflights users on 4/20. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/45:00 am
ONT
-
LHR
2 stops17h 30m
Air Canada
Wed 8/1910:15 am
LHR
-
ONT
2 stops42h 37m
Air Canada
Deal found 4/20$905
This United Airlines deal was found by Cheapflights users on 4/22. 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.
Mon 8/31:50 pm
ONT
-
LHR
1 stop13h 20m
United Airlines
Thu 8/209:30 am
LHR
-
ONT
2 stops20h 29m
United Airlines
Deal found 4/22$908
This Air Canada deal was found by Cheapflights users on 4/20. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/45:00 am
ONT
-
LHR
2 stops17h 30m
Air Canada
Fri 8/212:05 pm
LHR
-
ONT
2 stops38h 47m
Air Canada
Deal found 4/20$909
This Air Canada deal was found by Cheapflights users on 4/20. 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 Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/35:00 am
ONT
-
LHR
2 stops17h 35m
Air Canada
Wed 8/1910:15 am
LHR
-
ONT
2 stops42h 37m
Air Canada
Deal found 4/20$910
This Cheapflightsfares deal was found by Cheapflights users on 4/20. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/410:59 am
ONT
-
LHR
1 stop13h 06m
British Airways
Tue 5/1910:05 am
LHR
-
ONT
1 stop14h 17m
British Airways
Deal found 4/20$911

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 April 23, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$892
(Iberia)

One-way from

$448
(SmartFares)

Popular in

June

Cheapest in

November

Average price

$700
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. 26% potential increase in price ($308 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease ($47 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in April 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 April 23, 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 5/3

1:40 pm-12:35 pm

1 stop14h 55m

London Heathrow

Tue 5/19

2:50 pm-8:36 pm

1 stop13h 46m

$918

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 8/25

9:55 am-11:00 am

1 stop17h 05m

London Heathrow

Mon 9/7

6:30 am-6:01 pm

2 stops19h 31m

$946

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 8/18

5:26 pm-3:05 pm

1 stop13h 39m

London Heathrow

Tue 8/25

5:00 pm-11:24 pm

1 stop14h 24m

$1,125

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Thu 7/23

1:50 pm-11:10 am

1 stop13h 20m

London Heathrow

Tue 8/4

1:40 pm-9:55 pm

1 stop16h 15m

$1,165

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 7/20

1:50 pm-11:10 am

1 stop13h 20m

London Heathrow

Mon 7/27

4:15 pm-10:37 pm

1 stop14h 22m

$1,238

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 5/17

1:30 pm-11:10 am

1 stop13h 40m

London Heathrow

Sun 5/24

11:25 am-5:28 pm

1 stop14h 03m

$1,257

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 7/22

5:54 pm-3:05 pm

1 stop13h 11m

London Heathrow

Fri 7/31

5:00 pm-11:11 pm

1 stop14h 11m

$1,263

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 6/9

1:48 pm-12:10 pm

1 stop14h 22m

London Heathrow

Tue 6/16

11:45 am-10:41 pm

2 stops18h 56m

$1,279

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 6/7

1:18 pm-12:35 pm

1 stop15h 17m

London Heathrow

Sun 6/14

2:50 pm-8:42 pm

1 stop13h 52m

$1,318

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Fri 6/12

1:18 pm-9:40 am

1 stop12h 22m

London Heathrow

Tue 6/16

4:15 pm-10:37 pm

1 stop14h 22m

$1,328

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/18

Showing 1-10 of 23 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 April.
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, November is the cheapest month in which you can book a flight from Ontario to London Heathrow Airport (average of $624). Flying from Ontario to London Heathrow Airport in June is currently the most expensive (average of $1,380). 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 Heathrow Airport?

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 April 23, 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
8,444 reviews

Crew

8.5

Boarding

8.1

Food

7.2

Entertainment

7.8

Comfort

7.9

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
8,444 reviews
Delta
7.9
Good
8,444 reviews

Crew

8.5

Boarding

8.1

Food

7.2

Entertainment

7.8

Comfort

7.9

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.
KLM
7.8
Good
1,508 reviews
Delta
7.9
Good
8,444 reviews

Crew

8.5

Boarding

8.1

Food

7.2

Entertainment

7.8

Comfort

7.9

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
9,644 reviews
Delta
7.9
Good
8,444 reviews

Crew

8.5

Boarding

8.1

Food

7.2

Entertainment

7.8

Comfort

7.9

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
11,664 reviews
Delta
7.9
Good
8,444 reviews

Crew

8.5

Boarding

8.1

Food

7.2

Entertainment

7.8

Comfort

7.9

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
7,910 reviews
Delta
7.9
Good
8,444 reviews

Crew

8.5

Boarding

8.1

Food

7.2

Entertainment

7.8

Comfort

7.9

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 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, Delta, and Alaska Airlines can get you from Ontario to London Heathrow Airport in just under 13h 39m. Your travel time can differ by up to 3h 26m. 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 34% 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, November is the cheapest month in which you can book a flight from Ontario to London Heathrow Airport (average of $624). Flying from Ontario to London Heathrow Airport in June is currently the most expensive (average of $1,380). 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
Winchester
Croydon
Gatwick
Southend-on-Sea
Harrow
Eastleigh
Dartford
Dover
Orpington
Watford
Northampton
Borehamwood
Broadway
Chipping Norton
Hayes
Kingston upon Thames
Eastbourne
Slough

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 April 23, 2026.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$570Average$672FlexibilityNo cancel feeOn-timeN/A
KLMCheapest$580Average$672FlexibilityNo cancel feeOn-time75%
American AirlinesCheapest$624Average$678FlexibilityNo cancel feeOn-time71%
British AirwaysCheapest$624Average$872FlexibilityNo cancel feeOn-time70%
United AirlinesCheapest$662Average$941FlexibilityNo cancel feeOn-time69%

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