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$325+ 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 10/1. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LHR
Aug 23 — Aug 301
Sat 8/23
Sat 8/30
1 adult, Economy
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Cheapflights Tip: The best prices from Ontario to London Heathrow are usually found in October or April, booked 72 days in advance, depart on a Wednesday or Sunday and return on a Tuesday

Cheap 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 August 18, 2025.

Round-trip from

$524
(Delta)

One-way from

$325
(Kiwi.com)

Popular in

June

Cheapest in

October

Average price

$862
From Ontario to London Heathrow
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One-way flight from Ontario to London Heathrow
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Highest demand for flights based on searches. 22% potential increase in price ($244 potential increase over avg. RT price).
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Cheapest flight prices on average. 5% potential price decrease ($43 potential savings vs. average RT price).
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Average for round-trip flights in August 2025
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Find 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 August 18, 2025.

This Delta deal was found by Cheapflights users on 8/16. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/16:00 amONT - LHR
1 stop24h 15mDelta
Thu 10/306:20 amLHR - ONT
2 stops17h 50mDelta
Deal found 8/16$524
This KLM deal was found by Cheapflights users on 8/17. 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 KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/511:36 amONT - LHR
1 stop13h 24mKLM
Tue 11/1110:45 amLHR - ONT
1 stop13h 29mKLM
Deal found 8/17$532
This Delta deal was found by Cheapflights users on 8/17. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/1311:55 amONT - LHR
2 stops24h 05mDelta
Fri 9/2611:20 amLHR - ONT
1 stop15h 55mDelta
Deal found 8/17$537
This Delta deal was found by Cheapflights users on 8/16. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/255:50 pmONT - LHR
1 stop33h 40mDelta
Tue 11/42:45 pmLHR - ONT
1 stop34h 25mDelta
Deal found 8/16$542
This Delta deal was found by Cheapflights users on 8/18. 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.
Mon 9/1511:50 amONT - LHR
1 stop15h 30mDelta
Wed 9/2411:30 amLHR - ONT
2 stops19h 10mDelta
Deal found 8/18$563
This Delta deal was found by Cheapflights users on 8/16. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/1511:50 amONT - LHR
2 stops17h 40mDelta
Fri 9/266:15 amLHR - ONT
2 stops18h 45mDelta
Deal found 8/16$568
This KLM deal was found by Cheapflights users on 8/18. 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 KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/1511:55 amONT - LHR
1 stop17h 35mKLM
Wed 9/241:05 pmLHR - ONT
1 stop17h 18mKLM
Deal found 8/18$571
This Delta deal was found by Cheapflights users on 8/18. 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.
Fri 10/247:05 amONT - LHR
1 stop16h 10mDelta
Thu 10/306:20 amLHR - ONT
2 stops22h 00mDelta
Deal found 8/18$574
This Delta deal was found by Cheapflights users on 8/18. 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.
Thu 9/411:45 amONT - LHR
1 stop15h 25mDelta
Wed 9/108:40 amLHR - ONT
2 stops22h 02mDelta
Deal found 8/18$575
This Delta deal was found by Cheapflights users on 8/17. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/226:07 pmONT - LHR
1 stop34h 43mDelta
Fri 1/910:45 amLHR - ONT
1 stop18h 29mDelta
Deal found 8/17$576

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 August 18, 2025.
Use the filters below to find and compare flights from Ontario to London Heathrow Airport that are best for you.

Fly from

Ontario

Fly to

Heathrow

Route

Depart

Return

Price

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 9/23

9:55 am-9:50 am

1 stop15h 55m

London Heathrow

Thu 10/2

9:00 am-10:23 pm

2 stops21h 23m

$524

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 9/1

11:45 am-1:30 pm

1 stop17h 45m

London Heathrow

Tue 9/30

6:15 am-5:00 pm

2 stops18h 45m

$524

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 10/1

11:50 am-2:15 pm

1 stop18h 25m

London Heathrow

Wed 10/8

11:30 am-10:41 pm

2 stops19h 11m

$524

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 10/1

6:00 am-2:15 pm

1 stop24h 15m

London Heathrow

Thu 10/30

6:20 am-5:10 pm

2 stops17h 50m

$524

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 11/3

11:36 am-9:00 am

1 stop13h 24m

London Heathrow

Wed 11/12

10:45 am-4:14 pm

1 stop13h 29m

$532

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 11/4

11:36 am-9:00 am

1 stop13h 24m

London Heathrow

Wed 11/12

10:45 am-4:14 pm

1 stop13h 29m

$532

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 10/1

8:00 am-5:45 pm

3 stops49h 45m

$325

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Fri 9/19

12:13 pm-10:20 am

3 stops38h 07m

$354

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 10/1

9:36 am-2:10 pm

1 stop20h 34m

$394

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 10/22

4:49 pm-12:50 pm

1 stop12h 01m

$398

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/17

Showing 1-10 of 15 results
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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

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

Use this chart to determine the optimal time to book a round-trip flight from Ontario to Heathrow. Price data was last updated on August 8, 2025.

The price you pay for your flight from Ontario to London Heathrow Airport may vary depending on when you book. For the best chance of a lower fare, look to book 72 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

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 $661). Flying from Ontario to London Heathrow Airport in June is currently the most expensive (average of $1,097). 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.

What is the cheapest time of day to fly from ONT to LHR?

Find hourly flight availability from Ontario to Heathrow. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated August 18, 2025.

It’s typically best to fly out from Ontario to London Heathrow Airport in the morning. Doing so could potentially save you 32% on the flight price compared to flying in the evening, which is usually more expensive.

What is the cheapest day to fly from Ontario to London Heathrow Airport?

Use this chart to determine the cheapest time to fly round-trip from Ontario to Heathrow. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their Ontario to London Heathrow Airport flight should consider departing on Tuesday mornings when fares are most often at their lowest. Thursday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.

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 August 18, 2025.
Read through reviews of airlines operating flights from Ontario to London Heathrow Airport, such as Delta, United Airlines, and American Airlines. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Delta
8.0
Very good
7,981 reviews

Crew

8.5

Food

7.3

Overall

8.0

Boarding

8.2

Comfort

7.9

Entertainment

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
8.0
Very good
7,981 reviews
Delta
8.0
Very good
7,981 reviews

Crew

8.5

Food

7.3

Overall

8.0

Boarding

8.2

Comfort

7.9

Entertainment

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
8,925 reviews
Delta
8.0
Very good
7,981 reviews

Crew

8.5

Food

7.3

Overall

8.0

Boarding

8.2

Comfort

7.9

Entertainment

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
7.2
Good
10,000 reviews
Delta
8.0
Very good
7,981 reviews

Crew

8.5

Food

7.3

Overall

8.0

Boarding

8.2

Comfort

7.9

Entertainment

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.
Iberia
7.0
Good
2,884 reviews
Delta
8.0
Very good
7,981 reviews

Crew

8.5

Food

7.3

Overall

8.0

Boarding

8.2

Comfort

7.9

Entertainment

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
7,277 reviews
Delta
8.0
Very good
7,981 reviews

Crew

8.5

Food

7.3

Overall

8.0

Boarding

8.2

Comfort

7.9

Entertainment

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 7 different airlines.

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

    Delta can get you from Ontario to London Heathrow Airport in just under 15h 55m. Your travel time can differ by up to . The distance between Ontario and London Heathrow Airport is about 5407 mi.

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

    According to our current data, Delta ($572), KLM ($580), and Iberia ($582) offers the cheapest pricing from Ontario to London Heathrow Airport. Delta is 32% 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 $661). Flying from Ontario to London Heathrow Airport in June is currently the most expensive (average of $1,097). 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
Hounslow
Hayes
Thornton Heath
Harrow
Canterbury
Dartford
Dover
Stratford-upon-Avon
Orpington
Watford
Northampton
Gatwick
Borehamwood
Broadway
Aylesbury
Chelmsford
Southend-on-Sea
Folkestone
Chichester
Swindon

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Top 7 airlines flying from Ontario to Heathrow

Discover the top 7 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 August 18, 2025.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$572Average$705FlexibilityNo cancel feeOn-timeN/A
KLMCheapest$580Average$704FlexibilityNo cancel feeOn-time75%
IberiaCheapest$582Average$670FlexibilityNo cancel feeOn-time77%
Virgin AtlanticCheapest$629Average$889FlexibilityNo cancel feeOn-time72%
United AirlinesCheapest$660Average$788FlexibilityNo cancel feeOn-time69%
British AirwaysCheapest$662Average$877FlexibilityNo cancel feeOn-time70%
American AirlinesCheapest$687Average$958FlexibilityNo cancel feeOn-time71%

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