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Cheap flights from London to Ontario from £392

This is the cheapest retur flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 24/8. Fares are subject to change and may not be available on all flights or dates of travel.
LON — ONT
13 Jul — 20 Jul1
1 adult

Cheapflights Tip: The best prices from London to Ontario are usually found in February or January, booked 77 days in advance, depart on a Wednesday or Tuesday and return on a Monday

Cheap flight deals from London to Ontario

Discover tips and strategies to find the most affordable flight options for your journey from London (LON) to Ontario (ONT). 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 8 July 2025.

Round-trip from

£392

Popular in

August

Cheapest in

February

Average price

£764
KLM
  • KLM
  • 24/8-9/9
  • 2 total stops
  • 39h 20m total
  • London to Ontario
Highest demand for flights based on searches. 19% potential increase in price (£93 potential increase over avg. return price).
Cheapest flight prices on average. 4% potential price decrease (£19 potential savings vs. average return price).
Average for round-trip flights in July 2025

Find flight deals from London to Ontario

Cheapest flights from London to Ontario
Explore the most affordable flight options available from London to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 8 July 2025.

Sun 24/810:55LHR - ONT
1 stop20h 45mKLM
Tue 9/911:40ONT - LHR
1 stop18h 35mKLM
Deal found 7/7£392
Thu 28/815:05LGW - ONT
2 stops28h 27mMultiple Airlines
Wed 10/906:10ONT - LGW
2 stops18h 00mMultiple Airlines
Deal found 6/7£413
Sun 24/810:55LHR - ONT
1 stop20h 45mVirgin Atlantic
Tue 9/906:05ONT - LHR
2 stops40h 20mVirgin Atlantic
Deal found 7/7£416
Sun 31/815:10LHR - ONT
1 stop15h 04mFinnair
Sat 13/914:54ONT - LHR
1 stop13h 51mFinnair
Deal found 6/7£419
Fri 26/912:00LHR - ONT
1 stop14h 54mBritish Airways
Wed 8/1016:49ONT - LHR
1 stop12h 01mBritish Airways
Deal found 8/7£425
Mon 24/1119:05LHR - ONT
2 stops22h 23mIberia
Fri 5/1210:57ONT - LHR
1 stop15h 03mIberia
Deal found 7/7£428
Tue 25/1106:30LHR - ONT
2 stops24h 12mDelta
Fri 5/1211:29ONT - LHR
1 stop15h 31mDelta
Deal found 7/7£430
Mon 1/915:40LHR - ONT
1 stop13h 59mAmerican Airlines
Wed 17/916:45ONT - LHR
1 stop12h 05mAmerican Airlines
Deal found 8/7£443
Wed 3/912:00LHR - ONT
1 stop14h 54mMultiple Airlines
Tue 9/912:45ONT - LHR
1 stop14h 05mMultiple Airlines
Deal found 6/7£476
Sun 10/816:20LCY - ONT
2 stops51h 32mBritish Airways
Thu 21/810:50ONT - LCY
2 stops19h 35mBritish Airways
Deal found 6/7£535
Sat 15/1119:35LGW - ONT
2 stops30h 14mBritish Airways
Fri 21/1108:46ONT - LGW
2 stops26h 04mBritish Airways
Deal found 7/7£576
Thu 21/812:00LGW - ONT
2 stops42h 20mKLM
Mon 1/907:05ONT - LGW
2 stops42h 55mKLM
Deal found 7/7£609

Cheapflights Fare Finder

Customise your flight search to find flights from London to Ontario 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 8 July 2025.
Use the filters below to find and compare flights from London to Ontario that are best for you.

Fly from

London

Fly to

Ontario

Route

Depart

Return

Price

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Sun 24/8

10:55-23:40

1 stop20h 45m

Ontario

Tue 9/9

11:40-14:15

1 stop18h 35m

£392

LondonOntario

LGW - ONT

LGWONT

London Gatwick

Thu 28/8

15:05-11:32

2 stops28h 27m

Ontario

Wed 10/9

06:10-08:10

2 stops18h 00m

£413

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Sun 24/8

10:55-23:40

1 stop20h 45m

Ontario

Tue 9/9

06:05-06:25

2 stops40h 20m

£416

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Sun 31/8

15:10-22:14

1 stop15h 04m

Ontario

Sat 13/9

14:54-12:45

1 stop13h 51m

£419

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Fri 26/9

12:00-18:54

1 stop14h 54m

Ontario

Wed 8/10

16:49-12:50

1 stop12h 01m

£425

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Mon 24/11

19:05-09:28

2 stops22h 23m

Ontario

Fri 5/12

10:57-10:00

1 stop15h 03m

£428

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Tue 25/11

06:30-22:41

2 stops24h 11m

Ontario

Fri 5/12

06:00-12:15

2 stops22h 15m

£430

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Mon 1/9

15:40-21:39

1 stop13h 59m

Ontario

Wed 17/9

16:45-12:50

1 stop12h 05m

£443

LondonOntario

LHR - ONT

LHRONT

London Heathrow

Wed 3/9

12:00-18:54

1 stop14h 54m

Ontario

Tue 9/9

12:45-10:50

1 stop14h 05m

£476

LondonOntario

LCY - ONT

LCYONT

London City

Sun 10/8

16:20-11:52

2 stops51h 32m

Ontario

Thu 21/8

10:50-14:25

2 stops19h 35m

£535

Flights are sorted by cheapest return flights first.

Deals found on 7/7

Showing 1-10 of 35 results
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Best time to book a flight from London to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from London 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 London to Ontario

How far ahead should I book a flight from London to Ontario?

Use this chart to determine the optimal time to book a return flight from London to Ontario. Price data was last updated on 27 June 2025.

To ensure you get the cheapest price possible for a flight from London to Ontario, you should look to book at least 77 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.

What is the cheapest month to book a flight from London to Ontario?

Currently, March is the cheapest month in which you can book a flight from London to Ontario (average of £516). Flying from London to Ontario in August is currently the most expensive (average of £827). 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 LON to ONT?

Find hourly flight availability from London to Ontario. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 8 July 2025.

It’s optimal to fly from London to Ontario in the evening. By choosing this option you can save up to 15% on the cost of your flight, compared to a flight at midday.

How much does it cost for a return flight from London to Ontario?

Reviews of airlines servicing Ontario

Get insights into the airlines that provide service to Ontario. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Ontario. Reviews last updated 8 July 2025.
Read through reviews of airlines operating flights from London to Ontario, such as Delta, KLM, andFinnair. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.

Overall

8.0

Boarding

8.2

Crew

8.5

Entertainment

7.9

Comfort

7.9

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception
8.0
Very Good

Overall

8.0

Boarding

8.2

Crew

8.5

Entertainment

7.9

Comfort

7.9

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception

Overall

8.0

Boarding

8.2

Crew

8.5

Entertainment

7.9

Comfort

7.9

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception

Overall

8.0

Boarding

8.2

Crew

8.5

Entertainment

7.9

Comfort

7.9

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception

Overall

8.0

Boarding

8.2

Crew

8.5

Entertainment

7.9

Comfort

7.9

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception

Overall

8.0

Boarding

8.2

Crew

8.5

Entertainment

7.9

Comfort

7.9

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception

Related info for your journey

Find useful and relevant information for your journey from London to Ontario. 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 into for flights to Ontario from London?

    Most people fly into Ontario (ONT) if they book a flight to Ontario from London. On average, Ontario has 0 inbound flights from London per day from 6 airlines. Ontario is conveniently located just 3.1 mi from Ontario’s city center.

  • What are the cheapest airlines flying from London to Ontario round-trip?

    According to our current data, KLM (£392), Virgin Atlantic (£416), and Finnair (£419) offers the cheapest pricing from London to Ontario. You may be able to fly from London to Ontario for 27% less than the average price by searching for these airlines.

  • What are the cheapest airlines to fly from London to Ontario one-way?

    To fly one-way, consider booking your trip with British Airways, which is currently one of the cheapest options available, starting at £435. WestJet flights start at £488 while deals on Iberia start at £489 one-way.

  • What are the most popular routes from London to Ontario?

  • Can I find deals for flights from London to Ontario that include hotel bookings?

    Yes. In addition to deals on London to Ontario flights, Cheapflights offers holiday packages that include both flights and hotel.

  • How can I find direct flights from London to Ontario?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from London to Ontario.

  • Can I find deals for business class flights from London to Ontario?

    Yes. Cheapflights offers flight deals from London to Ontario 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 London to Ontario?

    Currently, March is the cheapest month in which you can book a flight from London to Ontario (average of £516). Flying from London to Ontario in August is currently the most expensive (average of £827). 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

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for London to Ontario

See prices for flight routes from nearby airports that may be better suited for you.

Top 6 airlines flying from London to Ontario

Discover the top 6 airlines that operate flights from London to Ontario. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 858,174 searches. Data last updated 8 July 2025.
AirlineCheapestAverageFlexibilityOn-time
FinnairCheapest£275Average£423FlexibilityNo cancel feeOn-time76%
Search Finnair flights
British AirwaysCheapest£373Average£480FlexibilityNo cancel feeOn-time70%
Search British Airways flights
KLMCheapest£373Average£587FlexibilityNo cancel feeOn-time75%
Search KLM flights
United AirlinesCheapest£390Average£581FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
Virgin AtlanticCheapest£401Average£505FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
LufthansaCheapest£425Average£547FlexibilityNo cancel feeOn-time76%
Search Lufthansa flights

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 London to Ontario?

When you search for this flight from London to Ontario, Cheapflights searches on 900+ travel sites to save you time finding great flight deals online. Additionally, we offer filter features so you can choose a preferred cabin class or airline, see different price ranges, and much more so you can book the flight for you.

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

Cheapflights helps you find that perfect flight to Ontario from London by searching from hundreds of airlines and agencies you know and love. We are also free to use, in case you were wondering!

Can Cheapflights find flights from London to Ontario with no change fees?

Cheapflights does show flights with no change fees to all users. To see these options for flights from London to Ontario, users can toggle the no change fees filter when performing a flight search.

Can Cheapflights notify me if prices for flights from London to Ontario become cheaper?

Yes, Cheapflights offers price alerts on London to Ontario flights so you can book your travel at the perfect time. Price Alerts can be enabled by clicking the bell icon next to the flight deals above and providing your email address where you want to receive the alerts.

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