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Cheap flights from Ontario to London from £279

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 27/5. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LON
2 Jun — 9 Jun1
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 3 May 2026.

Tue 6/1010:25
ONT
-
LHR
1 stop18h 25m
Iberia
Wed 14/1006:15
LHR
-
ONT
2 stops22h 53m
Iberia
Deal found 2/5£656
Mon 3/807:05
ONT
-
LHR
1 stop16h 10m
Delta
Thu 20/806:30
LHR
-
ONT
2 stops19h 31m
Delta
Deal found 28/4£660
Sat 31/1013:00
ONT
-
LHR
2 stops37h 20m
Air Canada
Fri 13/1114:30
LHR
-
ONT
2 stops35h 17m
Air Canada
Deal found 2/5£664
Wed 19/817:55
ONT
-
LHR
1 stop13h 40m
Delta
Wed 9/906:15
LHR
-
ONT
2 stops17h 59m
Delta
Deal found 28/4£665
Sun 1/1105:00
ONT
-
LHR
2 stops18h 10m
Air Canada
Fri 13/1114:30
LHR
-
ONT
2 stops40h 36m
Air Canada
Deal found 2/5£666
Sun 1/1113:00
ONT
-
LHR
1 stop12h 40m
United Airlines
Tue 10/1109:30
LHR
-
ONT
2 stops21h 36m
United Airlines
Deal found 2/5£668
Mon 17/813:44
ONT
-
LHR
1 stop16h 26m
United Airlines
Wed 2/909:30
LHR
-
ONT
2 stops20h 29m
United Airlines
Deal found 28/4£669
Tue 6/1005:00
ONT
-
LHR
2 stops17h 30m
Air Canada
Fri 16/1014:05
LHR
-
ONT
2 stops38h 47m
Air Canada
Deal found 29/4£669
Sat 31/1005:00
ONT
-
LHR
2 stops45h 20m
Air Canada
Thu 12/1111:10
LHR
-
ONT
2 stops41h 10m
Air Canada
Deal found 2/5£670
Sun 1/1116:47
ONT
-
LHR
1 stop12h 28m
British Airways
Tue 17/1116:30
LHR
-
ONT
1 stop15h 27m
British Airways
Deal found 30/4£671
Thu 26/1107:00
ONT
-
LGW
2 stops18h 00m
Delta
Fri 4/1210:00
LGW
-
ONT
2 stops20h 43m
Delta
Deal found 30/4£705
Sun 25/1007:00
ONT
-
LGW
2 stops25h 45m
Delta
Sun 1/1110:00
LGW
-
ONT
2 stops20h 43m
Delta
Deal found 28/4£705

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 3 May 2026.

Round-trip from

£656

One-way from

£279

Popular in

June

Cheapest in

March

Average price

£708
Iberia
  • Iberia
  • 6/10-14/10
  • 3 total stops
  • 41h 18m total
  • Ontario to London
Search Deals
27/5
  • 27/5
  • 3 total stops
  • 43h 25m total
  • Ontario to London
Search Deals
Highest demand for flights based on searches. 28% potential increase in price (£181 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease (£24 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 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 3 May 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 - LHR

ONTLHR

Ontario

Mon 3/8

11:48-11:20

1 stop15h 32m

London Heathrow

Thu 20/8

10:55-16:14

1 stop13h 19m

£681

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sat 3/10

13:18-09:40

1 stop12h 22m

London Heathrow

Sat 10/10

07:30-21:58

2 stops22h 28m

£742

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Mon 18/5

13:35-16:00

2 stops18h 25m

London Gatwick

Thu 8/10

10:25-22:43

2 stops20h 18m

£810

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Mon 18/5

13:35-16:00

2 stops18h 25m

London Gatwick

Wed 7/10

10:25-22:43

2 stops20h 18m

£810

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sat 5/9

23:24-20:45

1 stop13h 21m

London Heathrow

Fri 11/9

11:55-20:13

1 stop16h 18m

£817

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Mon 21/9

15:12-14:40

2 stops15h 28m

London Gatwick

Thu 15/10

15:40-22:39

2 stops38h 59m

£839

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Thu 1/10

21:10-20:45

1 stop15h 35m

London Heathrow

Tue 6/10

08:15-20:13

1 stop19h 58m

£856
Fastest return journey

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 27/7

13:00-10:00

1 stop13h 00m

London Heathrow

Sun 2/8

10:55-16:35

1 stop13h 40m

£858

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Mon 12/10

18:58-18:50

2 stops39h 52m

London Gatwick

Sat 17/10

10:20-22:39

2 stops20h 19m

£896

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 21/7

13:18-09:40

1 stop12h 22m

London Heathrow

Sat 1/8

07:45-21:55

2 stops22h 10m

£898

Flights are sorted by cheapest return flights first.

Deals found on 30/4

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 £185). Flying from Ontario to London in July is currently the most expensive (average of £531). 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 £665.

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 KLM, United Airlines, and Delta fly from Ontario to London in about 12h 22m. The time it takes to get you to your destination can typically vary by up to 6h 03m. 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 £185). Flying from Ontario to London in July is currently the most expensive (average of £531). 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?

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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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