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Cheap flights from Ontario to London from £240

ONT — LON
1 Nov — 8 Nov1
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

Wed 4/1106:30 -
2 stops29h 00m
Mon 9/1112:15 -
2 stops19h 36m
Deal found 30/9£604
Tue 10/1106:25 -
2 stops20h 25m
Tue 17/1112:15 -
2 stops19h 36m
Deal found 26/9£605
Wed 4/1106:25 -
2 stops29h 05m
Wed 11/1112:15 -
2 stops19h 36m
Deal found 26/9£606
Wed 11/1106:25 -
2 stops20h 25m
Mon 16/1120:35 -
2 stops35h 16m
Deal found 27/9£607
Sat 14/1106:25 -
2 stops29h 05m
Sat 21/1112:15 -
2 stops19h 59m
Deal found 30/9£612
Wed 11/1106:25 -
2 stops20h 25m
Tue 17/1112:15 -
2 stops19h 36m
Deal found 28/9£613
Mon 9/1106:25 -
2 stops29h 05m
Fri 13/1112:15 -
2 stops19h 36m
Deal found 30/9£625
Mon 26/1006:15 -
2 stops21h 35m
Mon 2/1120:35 -
2 stops35h 16m
Deal found 29/9£635
Mon 9/1106:30 -
2 stops20h 20m
Wed 18/1112:15 -
2 stops19h 36m
Deal found 30/9£641
Wed 11/1106:25 -
2 stops20h 25m
Wed 18/1112:15 -
2 stops19h 36m
Deal found 27/9£643

Find flight deals from Ontario to London

Round-trip from

£569

One-way from

£240

Popular in

July

Cheapest in

March

Average price

£875
United Airlines
  • United Airlines
  • 2/3-5/3
  • 3 total stops
  • 48h 44m total
  • Ontario to London
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JetBlue
  • JetBlue
  • 17/10-31/12
  • 1 total stop
  • 14h 03m total
  • Ontario to London
Search Deals
Highest demand for flights based on searches. 6% potential increase in price (£37 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease (£20 potential savings vs. average return price).
Search Deals
Average for round-trip flights in October 2026
Search Deals

Cheapflights Fare Finder

 
Use the filters below to find and compare flights from Ontario to London that are best for you.

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Route

Depart

Return

Price

Cheapest return flight

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Fri 9/10

23:05-20:45

1 stop13h 40m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£334

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Sun 1/11

06:00-10:15

1 stop20h 15m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£350

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Sat 31/10

12:16-07:50

1 stop36h 34m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£361
Fastest return journey

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Thu 11/2

16:59-13:35

1 stop12h 36m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£377

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Sun 29/11

06:00-07:25

1 stop17h 25m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£506

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Wed 2/12

05:45-07:40

1 stop17h 55m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£506

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Sat 17/10

22:42-12:10

2 stops29h 28m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£511

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Wed 2/12

10:05-10:50

2 stops16h 45m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£541

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Tue 20/10

10:25-11:55

2 stops17h 30m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£544

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Sun 15/11

14:45-21:05

2 stops22h 20m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£606

Flights are sorted by cheapest return flights first.

Deals found on 29/9

Showing 1-10 of 24 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

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, January is the cheapest month in which you can book a flight from Ontario to London (average of £520). Flying from Ontario to London in July is currently the most expensive (average of £1,003). 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’s the top stopover airport for flights from Ontario to London?

San Francisco (SFO) – 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?

San Francisco (SFO) is the most affordable one-stop option, with an average return flight price of £683.

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

Flights via Seattle (SEA) have the shortest average one-way travel time for one-stop routes: 13h 39m.

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

Flights via Seattle (SEA) offer the fastest connection on this route, with an average stopover time of 2h 30m.

Related info for your journey

  • 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, KLM, and Alaska Airlines fly from Ontario to London in about 13h 18m. The time it takes to get you to your destination can typically vary by up to 6h 42m. 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, January is the cheapest month in which you can book a flight from Ontario to London (average of £520). Flying from Ontario to London in July is currently the most expensive (average of £1,003). 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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Milton Keynes
Luton
Gatwick
Wembley
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Ilford
Hayes
Croydon
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Eastbourne
Enfield
Brentford
Southend-on-Sea
Barnet
Southall
Watford
Kingston upon Thames
Dagenham
Dover

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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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