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Cheap flights from Ontario to London from £275

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 4/2. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LON
21 Feb — 28 Feb1
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 22 January 2026.

Wed 4/307:00
ONT
-
LHR
1 stop17h 35m
Iberia
Wed 11/306:15
LHR
-
ONT
2 stops23h 15m
Iberia
Deal found 20/1£432
Wed 16/906:35
ONT
-
LGW
2 stops20h 05m
American Airlines
Wed 30/912:20
LGW
-
ONT
2 stops19h 57m
American Airlines
Deal found 21/1£438
Sun 23/810:50
ONT
-
LHR
1 stop17h 20m
Iberia
Tue 8/920:50
LHR
-
ONT
2 stops33h 00m
Iberia
Deal found 21/1£442
Tue 24/306:00
ONT
-
LHR
1 stop19h 15m
Iberia
Thu 16/411:30
LHR
-
ONT
2 stops20h 16m
Iberia
Deal found 20/1£444
Mon 23/214:39
ONT
-
LHR
1 stop13h 01m
British Airways
Tue 10/314:20
LHR
-
ONT
1 stop14h 47m
British Airways
Deal found 21/1£446
Thu 19/207:00
ONT
-
LHR
1 stop17h 15m
Iberia
Thu 26/220:50
LHR
-
ONT
2 stops33h 39m
Iberia
Deal found 20/1£448
Wed 11/215:09
ONT
-
LHR
1 stop13h 06m
British Airways
Wed 18/211:45
LHR
-
ONT
1 stop16h 00m
British Airways
Deal found 20/1£450
Tue 3/307:00
ONT
-
LHR
1 stop15h 50m
British Airways
Tue 10/310:15
LHR
-
ONT
1 stop15h 27m
British Airways
Deal found 21/1£451
Sat 31/110:58
ONT
-
LHR
1 stop35h 52m
Iberia
Tue 31/308:55
LHR
-
ONT
1 stop21h 54m
Iberia
Deal found 20/1£456
Wed 25/310:56
ONT
-
LHR
1 stop12h 54m
British Airways
Wed 1/416:10
LHR
-
ONT
1 stop14h 09m
British Airways
Deal found 20/1£457
Tue 24/317:02
ONT
-
LHR
1 stop13h 13m
British Airways
Wed 29/410:05
LHR
-
ONT
1 stop14h 17m
British Airways
Deal found 19/1£458
Wed 15/407:30
ONT
-
LGW
2 stops22h 20m
British Airways
Fri 24/411:30
LGW
-
ONT
2 stops20h 16m
British Airways
Deal found 21/1£458

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 22 January 2026.

Round-trip from

£432

One-way from

£275

Popular in

June

Cheapest in

February

Average price

£509
Iberia
  • Iberia
  • 4/3-11/3
  • 3 total stops
  • 40h 50m total
  • Ontario to London
Search Deals
British Airways
  • British Airways
  • 4/2
  • 1 total stop
  • 13h 06m total
  • Ontario to London
Search Deals
Highest demand for flights based on searches. 15% potential increase in price (£80 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease (£15 potential savings vs. average return price).
Search Deals
Average for round-trip flights in January 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 22 January 2026.
Use the filters below to find and compare flights from Ontario to London that are best for you.

Fly from

Ontario

Fly to

London

Route

Depart

Return

Price

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 25/3

10:56-06:50

1 stop12h 54m

London Heathrow

Tue 31/3

08:55-16:22

1 stop15h 27m

£453

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Wed 15/4

07:30-13:50

2 stops22h 20m

London Gatwick

Fri 24/4

11:30-23:46

2 stops20h 16m

£458

OntarioLondon

ONT - LCY

ONTLCY

Ontario

Wed 4/2

10:58-14:05

2 stops19h 07m

London City

Wed 11/2

07:50-22:48

2 stops22h 58m

£461

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 24/3

10:56-08:15

1 stop14h 19m

London Heathrow

Wed 1/4

10:05-16:22

1 stop14h 17m

£465

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 24/3

23:58-06:50

1 stop23h 52m

London Heathrow

Wed 15/4

16:25-23:46

1 stop15h 21m

£465

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sat 21/3

23:58-06:50

1 stop23h 52m

London Heathrow

Thu 16/4

08:55-18:37

1 stop17h 42m

£465

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 23/3

23:58-08:15

1 stop25h 17m

London Heathrow

Tue 14/4

10:05-16:22

1 stop14h 17m

£468

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Thu 5/3

07:30-11:55

1 stop20h 25m

London Heathrow

Thu 12/3

06:30-21:00

2 stops21h 30m

£469

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Thu 5/3

13:40-12:00

1 stop14h 20m

London Heathrow

Tue 10/3

10:05-17:41

1 stop14h 36m

£490

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Thu 5/3

07:30-10:30

1 stop19h 00m

London Heathrow

Thu 12/3

14:30-22:33

1 stop15h 03m

£490

Flights are sorted by cheapest return flights first.

Deals found on 20/1

Showing 1-10 of 58 results
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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, October is the cheapest month in which you can book a flight from Ontario to London (average of £165). Flying from Ontario to London in June is currently the most expensive (average of £422). 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 40% 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.

Phoenix (PHX) is the most affordable one-stop option, with an average return flight price of £472.

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 Phoenix (PHX) have the shortest average one-way travel time for one-stop routes: 12h 15m.

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 Phoenix (PHX) offer the fastest connection on this route, with an average stopover time of 1h 28m.

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 British Airways, Iberia, and Delta fly from Ontario to London in about 12h 54m. The time it takes to get you to your destination can typically vary by up to 6h 26m. 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, October is the cheapest month in which you can book a flight from Ontario to London (average of £165). Flying from Ontario to London in June is currently the most expensive (average of £422). 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?

Book flights to London if you plan to visit one of these locations
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Gatwick
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Ilford
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Hayes
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Watford
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Kingston upon Thames
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Eastbourne
Romford
Folkestone
Southend-on-Sea

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Fly with Cheapflights

Find the best flight deals on Cheapflights, where travellers can enjoy low prices and a wide availability of flights to their desired destinations.

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

Cheapflights helps you search for flights from Ontario to London via 900+ travel sites so you don’t have to. After performing a flight search, users can also filter their flight selection by filtering for price, number of stops, airlines, and so on.

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

Cheapflights taps into our reliable network of hundreds of airlines and travel agencies to find the best deals for flights from Ontario to London for you. Better yet — we are completely free to use.

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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