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Cheap flights from Ontario to London from £217

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 17/1. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LON
4 Jan — 11 Jan1
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 5 Dezember 2025.

Mi 10/1213:29ONT - LHR
1 stop12h 31mDelta
Mi 24/1210:45LHR - ONT
1 stop19h 48mDelta
Deal found 3/12£448
Mi 10/1213:34ONT - LHR
1 stop12h 06mUnited Airlines
Fr 9/110:00LHR - ONT
1 stop19h 58mUnited Airlines
Deal found 3/12£485
Do 11/1210:47ONT - LHR
1 stop15h 13mBritish Airways
Mo 15/1219:05LHR - ONT
2 stops26h 50mBritish Airways
Deal found 3/12£492
Do 11/1213:34ONT - LHR
1 stop12h 06mUnited Airlines
Do 18/1210:05LHR - ONT
1 stop15h 38mUnited Airlines
Deal found 3/12£505
Do 11/1206:40ONT - LHR
1 stop22h 10mDelta
Mo 15/1214:45LHR - ONT
1 stop16h 02mDelta
Deal found 4/12£523
Do 11/1213:50ONT - LHR
1 stop14h 10mUnited Airlines
Mo 15/1210:05LHR - ONT
1 stop15h 32mUnited Airlines
Deal found 2/12£524
Di 16/1206:00ONT - LHR
1 stop17h 30mUnited Airlines
Mi 24/1212:05LHR - ONT
1 stop17h 47mUnited Airlines
Deal found 3/12£527
Di 16/1206:00ONT - LHR
1 stop17h 30mUnited Airlines
Fr 9/115:10LHR - ONT
2 stops29h 07mUnited Airlines
Deal found 3/12£529
Mi 10/1213:50ONT - LHR
1 stop14h 10mUnited Airlines
So 14/1210:05LHR - ONT
1 stop15h 32mUnited Airlines
Deal found 3/12£579
Sa 13/1213:34ONT - LHR
1 stop12h 06mUnited Airlines
Mo 22/1213:45LHR - ONT
1 stop16h 56mUnited Airlines
Deal found 3/12£591
Do 11/1213:50ONT - LHR
1 stop14h 10mUnited Airlines
So 14/1210:05LHR - ONT
1 stop15h 32mUnited Airlines
Deal found 3/12£599
So 7/1223:59ONT - LGW
2 stops35h 01mBritish Airways
Mo 15/1219:40LGW - ONT
2 stops26h 15mBritish Airways
Deal found 4/12£857

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 5 Dezember 2025.

Round-trip from

£432

One-way from

£217

Popular in

June

Cheapest in

October

Average price

£564
Iberia
  • Iberia
  • 21/1-29/1
  • 3 total stops
  • 38h 20m total
  • Ontario to London
Search Deals
17/1
  • 17/1
  • 3 total stops
  • 38h 45m total
  • Ontario to London
Search Deals
Highest demand for flights based on searches. 14% potential increase in price (£73 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 December 2025
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 5 Dezember 2025.
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

Mi 15/4

11:55-14:15

1 stop18h 20m

London Heathrow

Di 5/5

06:15-17:16

2 stops19h 01m

£460

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mo 20/4

12:00-13:30

1 stop17h 30m

London Heathrow

Do 7/5

06:15-17:16

2 stops19h 01m

£460

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mi 15/4

17:02-15:05

1 stop14h 03m

London Heathrow

Di 5/5

16:25-23:40

1 stop15h 15m

£465

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mo 20/4

06:00-09:50

1 stop19h 50m

London Heathrow

Do 7/5

11:20-22:40

1 stop19h 20m

£465

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Fr 30/1

18:39-21:20

2 stops18h 41m

London Heathrow

Di 3/2

06:30-21:59

2 stops23h 29m

£477

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Di 20/1

13:24-09:40

1 stop12h 16m

London Heathrow

Mi 4/2

11:30-22:53

2 stops19h 23m

£477

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Fr 9/1

06:00-07:05

2 stops17h 05m

London Heathrow

So 18/1

06:20-21:48

2 stops23h 28m

£477

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Fr 9/1

13:24-09:40

1 stop12h 16m

London Heathrow

So 18/1

11:35-20:58

1 stop17h 23m

£483

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Fr 13/2

06:00-07:25

1 stop17h 25m

London Heathrow

Sa 21/2

12:05-21:59

1 stop17h 54m

£490

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Di 20/1

13:24-09:40

1 stop12h 16m

London Heathrow

Di 3/2

10:05-17:55

1 stop15h 50m

£490

Flights are sorted by cheapest return flights first.

Deals found on 3/12

Showing 1-10 of 57 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 £169). 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.

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

Find hourly flight availability from Ontario to London. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 5 Dezember 2025.

One of the essential ways to save on airfare from Ontario to London is to remain as flexible as possible. Flights that are in the evening tend to be the most expensive. A flight in the afternoon could potentially save you up to 43% on airfare.

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 £476.

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 Delta, British Airways, and KLM fly from Ontario to London in about 14h 03m. The time it takes to get you to your destination can typically vary by up to 5h 47m. 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 £169). 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

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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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