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Cheap flights from Ontario to London from £238

ONT — LON
29 Nov — 6 Dec1
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 2/1206:00 -
2 stops29h 30m
Wed 9/1212:15 -
2 stops18h 02m
Deal found 28/10£598
Thu 26/1106:45 -
2 stops28h 45m
Thu 3/1212:15 -
2 stops20h 02m
Deal found 28/10£604
Mon 7/1206:00 -
2 stops29h 30m
Tue 15/1212:15 -
2 stops18h 02m
Deal found 28/10£606
Tue 1/1219:06 -
3 stops31h 44m
Tue 8/1212:15 -
2 stops18h 02m
Deal found 30/10£630
Thu 3/1206:00 -
2 stops20h 50m
Mon 7/1220:35 -
2 stops33h 42m
Deal found 29/10£631
Fri 27/1110:55 -
3 stops26h 40m
Sun 6/1219:55 -
2 stops35h 28m
Deal found 27/10£636
Mon 16/1112:01 -
2 stops25h 39m
Sat 21/1106:40 -
2 stops25h 44m
Deal found 26/10£637
Wed 25/1106:45 -
2 stops28h 45m
Wed 2/1220:35 -
2 stops35h 42m
Deal found 28/10£638
Thu 3/1206:00 -
2 stops20h 50m
Thu 10/1212:15 -
2 stops20h 05m
Deal found 30/10£639

Find flight deals from Ontario to London

Round-trip from

£567

One-way from

£238

Popular in

July

Cheapest in

March

Average price

£795
United Airlines
  • United Airlines
  • 2/3-5/3
  • 4 total stops
  • 55h 19m total
  • Ontario to London
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Air Canada
  • Air Canada
  • 3/2-31/12
  • 2 total stops
  • 18h 05m total
  • Ontario to London
Search Deals
Highest demand for flights based on searches. 8% potential increase in price (£47 potential increase over avg. return price).
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Cheapest flight prices on average. 4% potential price decrease (£20 potential savings vs. average return price).
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Average for round-trip flights in October 2026
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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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Fly to

Route

Depart

Return

Price

Cheapest return flight

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Sun 25/4

08:00-07:25

1 stop15h 25m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£250

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Sat 17/4

18:53-11:10

1 stop32h 17m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£255

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Mon 7/12

07:00-05:55

1 stop14h 55m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£531

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Wed 25/11

05:00-09:40

1 stop20h 40m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£531

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Tue 24/11

07:00-12:00

1 stop21h 00m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£531
Fastest return journey

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Tue 8/12

13:40-09:40

1 stop12h 00m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£531

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Wed 13/1

11:15-10:50

2 stops15h 35m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£539

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Wed 23/12

05:00-06:30

3 stops41h 30m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£541

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Sat 19/12

23:52-05:55

1 stop22h 03m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£543

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Mon 21/12

05:55-07:40

1 stop17h 45m

London Heathrow

Wed 31/12

00:00-15:00

Nonstop0h 00m

£543

Flights are sorted by cheapest return flights first.

Deals found on 27/10

Showing 1-10 of 22 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, December is the cheapest month in which you can book a flight from Ontario to London (average of £554). Flying from Ontario to London in July is currently the most expensive (average of £994). 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?

Airfare is typical for this route at the moment.
Ontario to London flights typically cost between £543 and £717 in March.
The cheapest return price found within the last 5 days was £567 on United Airlines (2 Mar–5 Mar).

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 United Airlines and Alaska Airlines fly from Ontario to London in about 16h 44m. The time it takes to get you to your destination can typically vary by up to 14h 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, December is the cheapest month in which you can book a flight from Ontario to London (average of £554). Flying from Ontario to London in July is currently the most expensive (average of £994). 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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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.

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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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