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Cheap flights from Ontario to London from £223

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 11/11. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LON
13 Sep — 20 Sep1
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 14 August 2026.

Sun 8/1112:42 -
1 stop13h 18m
Sun 15/1114:45 -
1 stop16h 21m
Deal found 10/8£594
Wed 9/1206:00 -
1 stop22h 20m
Mon 14/1214:45 -
1 stop15h 54m
Deal found 13/8£597
Wed 7/1022:42 -
1 stop14h 03m
Wed 14/1017:00 -
1 stop33h 00m
Deal found 10/8£599
Sun 15/1106:00 -
1 stop22h 20m
Wed 25/1114:45 -
1 stop28h 26m
Deal found 13/8£600
Tue 8/1212:46 -
1 stop13h 14m
Tue 15/1214:45 -
1 stop16h 12m
Deal found 10/8£614
Mon 19/1023:05 -
1 stop13h 40m
Mon 2/1115:00 -
2 stops26h 40m
Deal found 10/8£615
Mon 23/1106:00 -
1 stop22h 20m
Mon 30/1113:15 -
1 stop13h 50m
Deal found 11/8£619
Sat 14/1116:09 -
1 stop36h 11m
Mon 30/1113:15 -
1 stop13h 50m
Deal found 12/8£627
Sun 11/1023:05 -
1 stop13h 40m
Tue 13/1006:15 -
2 stops21h 39m
Deal found 13/8£628
Thu 10/1214:22 -
1 stop13h 38m
Thu 17/1214:45 -
1 stop17h 11m
Deal found 12/8£631
Tue 17/1106:00 -
2 stops16h 30m
Sat 21/1106:00 -
2 stops20h 57m
Deal found 11/8£634
Fri 13/1112:02 -
1 stop16h 18m
Wed 18/1114:45 -
1 stop28h 33m
Deal found 9/8£636

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 14 August 2026.

Round-trip from

£572

One-way from

£223

Popular in

July

Cheapest in

March

Average price

£756
United Airlines
  • United Airlines
  • 7/2-10/2
  • 4 total stops
  • 62h 45m total
  • Ontario to London
Search Deals
11/11
  • 11/11
  • 3 total stops
  • 31h 00m total
  • Ontario to London
Search Deals
Highest demand for flights based on searches. 13% potential increase in price (£69 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease (£22 potential savings vs. average return price).
Search Deals
Average for round-trip flights in August 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 14 August 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 Ontario - LHR London Heathrow

ONTLHR

Ontario

Sat 19/9

22:39-20:45

1 stop14h 06m

London Heathrow

Mon 21/9

08:15-20:57

1 stop20h 42m

£663

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Mon 14/9

22:39-20:45

1 stop14h 06m

London Heathrow

Fri 2/10

11:55-20:57

1 stop17h 02m

£663

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Mon 14/9

22:39-20:45

1 stop14h 06m

London Heathrow

Sat 3/10

11:55-20:57

1 stop17h 02m

£663

OntarioLondon

ONT Ontario - LCY London City

ONTLCY

Ontario

Wed 7/10

06:20-09:30

2 stops19h 10m

London City

Wed 14/10

10:00-22:43

2 stops20h 43m

£691

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Sun 18/10

11:13-15:05

1 stop19h 52m

London Heathrow

Thu 5/11

14:45-23:06

1 stop16h 21m

£692

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Sun 13/9

15:14-15:05

1 stop15h 51m

London Heathrow

Wed 7/10

17:00-10:17

1 stop25h 17m

£709

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Wed 9/9

09:01-11:10

1 stop18h 09m

London Heathrow

Wed 16/9

14:10-22:59

1 stop16h 49m

£717

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Thu 5/11

09:25-11:15

1 stop17h 50m

London Heathrow

Wed 18/11

07:40-18:47

1 stop19h 07m

£728

OntarioLondon

ONT Ontario - LGW London Gatwick

ONTLGW

Ontario

Wed 9/9

07:05-09:25

2 stops18h 20m

London Gatwick

Wed 16/9

10:25-20:24

2 stops17h 59m

£741

OntarioLondon

ONT Ontario - LGW London Gatwick

ONTLGW

Ontario

Wed 21/10

14:13-14:40

2 stops16h 27m

London Gatwick

Wed 18/11

11:55-21:40

2 stops17h 45m

£803

Flights are sorted by cheapest return flights first.

Deals found on 9/8

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, March is the cheapest month in which you can book a flight from Ontario to London (average of £482). Flying from Ontario to London in July is currently the most expensive (average of £980). 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 below average for this route at the moment.
Ontario to London flights typically cost between £609 and £802 in February.
The cheapest return price found within the last 5 days was £572 on United Airlines (7 Feb–10 Feb).

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.

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?

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 £668.

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 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?

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

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 JetBlue, Delta, and Alaska Airlines fly from Ontario to London in about 14h 06m. The time it takes to get you to your destination can typically vary by up to 5h 46m. 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, March is the cheapest month in which you can book a flight from Ontario to London (average of £482). Flying from Ontario to London in July is currently the most expensive (average of £980). 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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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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