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Cheap flights from Ontario to London Heathrow Airport from £236

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 6/10. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LHR
25 Jun — 2 Jul1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Ontario to Heathrow

Enter your travel dates to find the best prices.

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 26 May 2026.

Tue 25/807:06
ONT
-
LHR
2 stops20h 54m
Multiple Airlines
Thu 27/812:00
LHR
-
ONT
1 stop18h 04m
Multiple Airlines
Deal found 24/5£580
Mon 14/912:35
ONT
-
LHR
1 stop16h 15m
Multiple Airlines
Mon 28/919:30
LHR
-
ONT
2 stops34h 28m
Multiple Airlines
Deal found 25/5£636
Tue 3/1110:47
ONT
-
LHR
1 stop13h 28m
British Airways
Tue 10/1115:00
LHR
-
ONT
1 stop15h 23m
British Airways
Deal found 22/5£638
Mon 2/1110:47
ONT
-
LHR
1 stop17h 13m
Iberia
Mon 9/1119:40
LHR
-
ONT
2 stops24h 13m
Iberia
Deal found 26/5£639
Tue 3/1106:10
ONT
-
LHR
1 stop19h 50m
Iberia
Tue 10/1106:00
LHR
-
ONT
2 stops24h 23m
Iberia
Deal found 26/5£642
Sun 23/811:45
ONT
-
LHR
1 stop19h 50m
KLM
Tue 8/906:30
LHR
-
ONT
2 stops18h 46m
KLM
Deal found 23/5£642
Wed 26/814:27
ONT
-
LHR
2 stops19h 48m
Multiple Airlines
Mon 7/908:55
LHR
-
ONT
1 stop20h 17m
Multiple Airlines
Deal found 22/5£644
Tue 3/1107:00
ONT
-
LHR
2 stops18h 20m
Delta
Tue 10/1106:30
LHR
-
ONT
2 stops18h 47m
Delta
Deal found 26/5£645
Wed 2/917:55
ONT
-
LHR
1 stop13h 40m
Delta
Tue 8/906:15
LHR
-
ONT
2 stops17h 59m
Delta
Deal found 23/5£648
Mon 2/1109:55
ONT
-
LHR
2 stops16h 50m
Delta
Tue 10/1106:30
LHR
-
ONT
2 stops18h 47m
Delta
Deal found 24/5£648
Mon 16/1110:47
ONT
-
LHR
2 stops18h 03m
Iberia
Thu 26/1106:15
LHR
-
ONT
2 stops24h 08m
Iberia
Deal found 24/5£649
Sun 27/915:14
ONT
-
LHR
1 stop15h 51m
Alaska Airlines
Wed 14/1017:00
LHR
-
ONT
1 stop14h 42m
Alaska Airlines
Deal found 25/5£650

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 26 May 2026.

Round-trip from

£580

One-way from

£236

Popular in

June

Cheapest in

November

Average price

£830
British Airways
  • British Airways
  • 25/8-27/8
  • 3 total stops
  • 38h 58m total
  • Ontario to London
Search Deals
British Airways
  • British Airways
  • 6/10
  • 1 total stop
  • 12h 59m total
  • Ontario to London
Search Deals
Highest demand for flights based on searches. 31% potential increase in price (£226 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 7% potential price decrease (£35 potential savings vs. average return price).
Search Deals
Average for round-trip flights in May 2026
Search Deals

Cheapflights Fare Finder

 
Customise 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 858,174 searches. Data last updated 26 May 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 return flight

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 23/8

11:45-15:35

1 stop19h 50m

London Heathrow

Tue 8/9

06:30-17:16

2 stops18h 46m

£642

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 14/10

14:14-15:05

1 stop16h 51m

London Heathrow

Thu 22/10

17:00-23:42

1 stop14h 42m

£650

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 1/11

06:00-12:20

1 stop22h 20m

London Heathrow

Fri 29/1

14:45-22:39

1 stop15h 54m

£650

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 3/8

06:10-06:45

1 stop16h 35m

London Heathrow

Thu 20/8

06:55-20:53

2 stops21h 58m

£663

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 9/8

17:26-15:05

1 stop13h 39m

London Heathrow

Wed 19/8

17:00-23:24

1 stop14h 24m

£684

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Fri 18/9

12:12-15:05

1 stop18h 53m

London Heathrow

Fri 2/10

17:00-23:24

1 stop14h 24m

£687

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 4/8

17:26-15:05

1 stop13h 39m

London Heathrow

Fri 14/8

17:00-23:11

1 stop14h 11m

£722
Fastest return journey

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 18/11

12:00-09:00

1 stop13h 00m

London Heathrow

Sun 29/11

10:45-16:12

1 stop13h 27m

£757

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 20/7

17:26-15:05

1 stop13h 39m

London Heathrow

Wed 29/7

17:00-23:11

1 stop14h 11m

£774

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 20/7

17:26-15:05

1 stop13h 39m

London Heathrow

Thu 30/7

17:00-23:11

1 stop14h 11m

£774

Flights are sorted by cheapest return flights first.

Deals found on 26/5

Showing 1-10 of 23 resultsSorted by cheapest first
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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 return 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 £462). Flying from Ontario to London Heathrow Airport in June is currently the most expensive (average of £1,180). 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 for a return flight from Ontario to London Heathrow Airport?

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?

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

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

    KLM, Alaska Airlines, and United Airlines can get you from Ontario to London Heathrow Airport in just under 16h 35m. Your travel time can differ by up to 3h 15m. The distance between Ontario and London Heathrow Airport is about 5407 mi. This flight may include one or multiple stops.

  • 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 holiday 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 £462). Flying from Ontario to London Heathrow Airport in June is currently the most expensive (average of £1,180). 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

Travelling to a place near London Heathrow Airport?

Book flights to London Heathrow Airport if you plan to visit one of these locations
Hounslow
Milton Keynes
Northampton
Wembley
Luton
Gatwick
Croydon
Ilford
Slough
Hayes
Brentford
Colchester
Kingston upon Thames
Eastbourne
Ipswich
Watford
Swindon
Romford
Guildford
Borehamwood

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How does Cheapflights help users find flights from Ontario to Heathrow?

When you search for this flight from Ontario to Heathrow, Cheapflights searches on 900+ travel sites to save you time finding great flight deals online. Additionally, we offer filter features so you can choose a preferred cabin class or airline, see different price ranges, and much more so you can book the flight for you.

Why should you use Cheapflights to find cheap flight tickets from Ontario to Heathrow?

It’s simple! Cheapflights, which is free to use for everyone, saves millions of users time and money every year by helping them find the cheapest and most suitable flights from Ontario to Heathrow.

Can Cheapflights find flights from Ontario to Heathrow with no change fees?

Certainly. Search results for flights to Heathrow from Ontario shown to you on Cheapflights can be narrowed down with different useful search filters, which includes flexible booking options.

Can Cheapflights notify me if prices for flights from Ontario to Heathrow become cheaper?

Yes, and it’s super simple to set up. Click the bell icon next to the flight deals above and provide a valid email address to enable Price Alerts. That’s it!

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