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Cheap flights from Ontario to London from £239

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 14/10. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LON
15 Aug — 22 Aug1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Ontario to London

Enter your travel dates to find the best prices.

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 16 July 2026.

Tue 1/1206:10
ONT
-
LHR
1 stop19h 50m
Iberia
Fri 11/1219:40
LHR
-
ONT
2 stops22h 14m
Iberia
Deal found 12/7£612
Mon 19/1012:43
ONT
-
LHR
1 stop16h 07m
British Airways
Tue 20/1016:25
LHR
-
ONT
1 stop25h 10m
British Airways
Deal found 15/7£614
Mon 23/1109:00
ONT
-
LHR
2 stops18h 50m
Multiple Airlines
Fri 4/1208:20
LHR
-
ONT
1 stop21h 59m
Multiple Airlines
Deal found 12/7£615
Tue 13/1008:03
ONT
-
LHR
2 stops21h 17m
Multiple Airlines
Thu 15/1017:00
LHR
-
ONT
1 stop25h 21m
Multiple Airlines
Deal found 13/7£624
Sun 15/1114:59
ONT
-
LHR
1 stop13h 01m
Multiple Airlines
Fri 27/1114:45
LHR
-
ONT
1 stop15h 54m
Multiple Airlines
Deal found 15/7£626
Sun 11/1011:13
ONT
-
LHR
1 stop19h 52m
Alaska Airlines
Sat 17/1017:00
LHR
-
ONT
1 stop14h 45m
Alaska Airlines
Deal found 11/7£627
Wed 30/1214:42
ONT
-
LHR
1 stop13h 33m
British Airways
Mon 11/114:45
LHR
-
ONT
1 stop16h 04m
British Airways
Deal found 14/7£634
Sun 13/1210:47
ONT
-
LHR
1 stop13h 28m
British Airways
Sat 9/114:45
LHR
-
ONT
1 stop16h 04m
British Airways
Deal found 11/7£638
Wed 18/1112:00
ONT
-
LHR
1 stop16h 20m
Multiple Airlines
Sun 29/1113:15
LHR
-
ONT
1 stop16h 44m
Multiple Airlines
Deal found 15/7£639
Mon 12/1011:13
ONT
-
LHR
1 stop19h 52m
Multiple Airlines
Sun 25/1013:15
LHR
-
ONT
1 stop15h 39m
Multiple Airlines
Deal found 16/7£640
Mon 28/1207:00
ONT
-
LGW
2 stops24h 45m
Delta
Wed 6/110:00
LGW
-
ONT
2 stops38h 12m
Delta
Deal found 15/7£705
Mon 17/806:20
ONT
-
LGW
2 stops25h 40m
Delta
Thu 27/810:25
LGW
-
ONT
2 stops20h 20m
Delta
Deal found 11/7£707

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 16 July 2026.

Round-trip from

£612

One-way from

£239

Popular in

July

Cheapest in

June

Average price

£900
Iberia
  • Iberia
  • 1/12-11/12
  • 3 total stops
  • 42h 04m total
  • Ontario to London
Search Deals
British Airways
  • British Airways
  • 14/10
  • 1 total stop
  • 13h 25m total
  • Ontario to London
Search Deals
Highest demand for flights based on searches. 12% potential increase in price (£63 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease (£20 potential savings vs. average return price).
Search Deals
Average for round-trip flights in July 2026
Search Deals

Cheapflights Fare Finder

 
Customise 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 858,174 searches. Data last updated 16 July 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 return flight

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Mon 14/9

07:05-09:40

2 stops18h 35m

London Gatwick

Fri 25/9

10:25-22:26

2 stops20h 01m

£707

OntarioLondon

ONT - LCY

ONTLCY

Ontario

Wed 12/8

06:20-09:30

2 stops19h 10m

London City

Wed 19/8

07:45-19:53

2 stops20h 08m

£719

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Fri 23/10

14:13-15:05

1 stop16h 52m

London Heathrow

Sun 8/11

14:45-22:54

1 stop16h 09m

£726
Fastest return journey

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 27/9

13:04-10:30

1 stop13h 26m

London Heathrow

Mon 5/10

16:10-21:54

1 stop13h 44m

£731

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 25/8

13:18-09:40

1 stop12h 22m

London Heathrow

Mon 7/9

13:00-22:59

1 stop17h 59m

£751

OntarioLondon

ONT - LCY

ONTLCY

Ontario

Wed 23/9

13:04-16:40

2 stops19h 36m

London City

Mon 28/9

09:20-22:40

2 stops21h 20m

£753

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Thu 27/8

13:18-09:40

1 stop12h 22m

London Heathrow

Thu 3/9

13:00-20:01

1 stop15h 01m

£757

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 1/9

09:15-07:55

1 stop14h 40m

London Heathrow

Sun 13/9

14:50-20:53

1 stop14h 03m

£757

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Mon 17/8

12:25-11:45

2 stops15h 20m

London Gatwick

Tue 1/9

13:00-22:00

2 stops17h 00m

£764

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Wed 19/8

10:55-11:45

2 stops16h 50m

London Gatwick

Tue 1/9

13:00-22:00

2 stops17h 00m

£771

Flights are sorted by cheapest return flights first.

Deals found on 15/7

Showing 1-10 of 60 resultsSorted by cheapest first
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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 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

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

Currently, September is the cheapest month in which you can book a flight from Ontario to London (average of £187). Flying from Ontario to London in July is currently the most expensive (average of £603). 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?

What’s the top stopover airport for flights from Ontario to London?

Share of one-stop return flights from Ontario to London chosen by Cheapflights users in the past 12 months, using the same stopover each way.

Dallas (DFW) – chosen by Cheapflights users on 50% of one-stop itineraries from Ontario to London on Cheapflights.

What’s the cheapest stopover airport for flights from Ontario to London?

Average return fare for one-stop flights from Ontario to London, chosen by Cheapflights users in the past 12 months, with the same stopover each way.

San Francisco (SFO) is the most affordable one-stop option, with an average return flight price of £671.

What’s the fastest stopover option from Ontario to London?

Shortest average travel time for one-stop one-way flights from Ontario to London, based on itineraries clicked by Cheapflights users over the past 12 months, grouped by stopover airport.

Flights via San Francisco (SFO) have the shortest average one-way travel time for one-stop routes: 13h 49m.

Which airport typically offers the quickest stopover for flights from Ontario to London?

Average stopover duration for one-stop one-way flights from Ontario to London, chosen by Cheapflights users in the last 12 months, grouped by stopover airport.

Flights via San Francisco (SFO) offer the fastest connection on this route, with an average stopover time of 2h 32m.

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?

    Ontario (ONT), located 3.1 mi from the city center, is the airport you fly out of when you book flights from Ontario to London. 0 airlines have flights from Ontario to London on a regular basis. Booking flights from Ontario to London should not be difficult; the airport handles an average of 0 outbound flights to London per day.

  • How long is the flight from Ontario to London?

    Airlines like Delta, Alaska Airlines, and British Airways fly from Ontario to London in about 13h 26m. The time it takes to get you to your destination can typically vary by up to 5h 09m. The distance between Ontario and London is about 5407 mi. This flight may include one or multiple stops.

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

    When deciding which route to take from Ontario to London consider Ontario - London Heathrow, Ontario - London Gatwick or Ontario - London City as they are the most popular.

  • 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 holiday 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, September is the cheapest month in which you can book a flight from Ontario to London (average of £187). Flying from Ontario to London in July is currently the most expensive (average of £603). 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

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

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

Yes! Cheapflights helps users easily find flights from Ontario to London with no change fees.

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

Yes! Start tracking prices for Ontario to London flights today and get alerted whenever prices for these flights change. To access this feature, click the bell icon next to the flight deals above, which will prompt you for a valid email address to receive your alerts.

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