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$374+ Cheap flights from Ontario (ONT) to London (LON)

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 9/27. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LON
Aug 21 — Aug 281
Thu 8/21
Thu 8/28
1 adult, Economy
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Cheap 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 August 16, 2025.

Round-trip from

$500
(Netflights)

One-way from

$374
(JetBlue)

Popular in

December

Cheapest in

September

Average price

$758
From Ontario to London (LON)
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One-way flight from Ontario to London (LON)
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Highest demand for flights based on searches. 4% potential increase in price ($41 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease ($31 potential savings vs. average RT price).
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Average for round-trip flights in August 2025
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Find flight deals from Ontario to London

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 August 16, 2025.

This Netflights deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Netflights is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/111:45 amONT - LHR
1 stop17h 45mVirgin Atlantic
Wed 9/101:25 pmLHR - ONT
1 stop17h 17mVirgin Atlantic
Deal found 8/14$500
This Delta deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/2511:45 amONT - LHR
1 stop15h 25mDelta
Wed 9/109:20 amLHR - ONT
1 stop17h 51mDelta
Deal found 8/15$522
This Delta deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/111:50 amONT - LHR
1 stop15h 30mDelta
Thu 10/306:20 amLHR - ONT
2 stops23h 21mDelta
Deal found 8/14$523
This KLM deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/211:36 amONT - LHR
1 stop13h 24mKLM
Tue 11/1810:45 amLHR - ONT
1 stop13h 29mKLM
Deal found 8/14$525
This Delta deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/306:00 amONT - LHR
2 stops17h 05mDelta
Fri 1/98:55 amLHR - ONT
2 stops20h 19mDelta
Deal found 8/14$528
This Delta deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/2811:48 amONT - LHR
1 stop15h 42mDelta
Tue 11/410:45 amLHR - ONT
1 stop18h 35mDelta
Deal found 8/14$531
This Delta deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/237:05 amONT - LGW
2 stops18h 55mDelta
Sat 8/3012:00 pmLGW - ONT
2 stops30h 20mDelta
Deal found 8/14$593
This Iberia deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/187:00 amONT - LGW
2 stops19h 50mIberia
Tue 12/211:45 amLGW - ONT
2 stops55h 45mIberia
Deal found 8/14$706
This American Airlines deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/296:10 amONT - LGW
2 stops18h 25mAmerican Airlines
Mon 10/610:40 amLGW - ONT
2 stops19h 09mAmerican Airlines
Deal found 8/15$714
This American Airlines deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/61:10 pmONT - LGW
2 stops35h 25mAmerican Airlines
Fri 9/1912:20 pmLGW - ONT
2 stops18h 13mAmerican Airlines
Deal found 8/15$799
This Delta deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/281:15 pmONT - LCY
2 stops19h 25mDelta
Sun 10/51:45 pmLCY - ONT
2 stops17h 57mDelta
Deal found 8/14$829
This Icelandair deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Icelandair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/78:30 amONT - LGW
2 stops18h 25mMultiple Airlines
Tue 11/1111:55 amLGW - ONT
2 stops18h 10mMultiple Airlines
Deal found 8/15$1,055

Cheapflights Fare Finder

 
Customize 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 2,558,603 searches. Data last updated August 16, 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

Mon 9/1

11:45 am-1:30 pm

1 stop17h 45m

London Heathrow

Wed 9/10

1:25 pm-10:42 pm

1 stop17h 17m

$500

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 8/25

11:45 am-11:10 am

1 stop15h 25m

London Heathrow

Wed 9/10

9:20 am-7:11 pm

1 stop17h 51m

$522

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 8/25

1:15 pm-9:50 am

1 stop12h 35m

London Heathrow

Tue 9/9

1:25 pm-10:42 pm

1 stop17h 17m

$522

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 12/30

6:45 am-12:50 pm

1 stop22h 05m

London Heathrow

Fri 1/9

8:55 am-9:14 pm

2 stops20h 19m

$523

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 10/1

11:50 am-11:20 am

1 stop15h 30m

London Heathrow

Thu 10/30

6:20 am-10:41 pm

2 stops23h 21m

$523

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 11/2

11:36 am-9:00 am

1 stop13h 24m

London Heathrow

Tue 11/18

10:45 am-4:14 pm

1 stop13h 29m

$525

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 11/4

11:36 am-9:00 am

1 stop13h 24m

London Heathrow

Tue 11/18

10:45 am-4:14 pm

1 stop13h 29m

$530

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Tue 11/18

7:00 am-10:50 am

2 stops19h 50m

London Gatwick

Tue 12/2

11:45 am-11:30 am

2 stops55h 45m

$706

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Mon 9/29

6:10 am-8:35 am

2 stops18h 25m

London Gatwick

Mon 10/6

10:40 am-9:49 pm

2 stops19h 09m

$714

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Sat 9/6

1:10 pm-8:35 am

2 stops35h 25m

London Gatwick

Fri 9/19

12:20 pm-10:33 pm

2 stops18h 13m

$799

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/14

Showing 1-10 of 60 results
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6

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 round-trip 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, November is the cheapest month in which you can book a flight from Ontario to London (average of $661). Flying from Ontario to London in June is currently the most expensive (average of $1,097). 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 August 16, 2025.

It’s optimal to fly from Ontario to London in the evening. By choosing this option you can save up to 24% on the cost of your flight, compared to a flight in the morning.

What is the cheapest day to fly from Ontario to London?

Use this chart to determine the cheapest time to fly round-trip from Ontario to London. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their Ontario to London flight should consider departing on Tuesday afternoons when fares are most often at their lowest. Sunday evenings flights should be avoided if possible as fares are typically the most expensive at this time.

Reviews of airlines servicing London

Get insights into the airlines that provide service to London. 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 London. Reviews last updated August 16, 2025.
Get a feel of what it's like to fly with Delta, United Airlines, and American Airlines from Ontario to London by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
8.0
Very good
7,985 reviews

Boarding

8.2

Overall

8.0

Entertainment

7.9

Comfort

7.9

Crew

8.5

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
Delta
8.0
Very good
7,985 reviews
Delta
8.0
Very good
7,985 reviews

Boarding

8.2

Overall

8.0

Entertainment

7.9

Comfort

7.9

Crew

8.5

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
United Airlines
7.4
Good
8,916 reviews
Delta
8.0
Very good
7,985 reviews

Boarding

8.2

Overall

8.0

Entertainment

7.9

Comfort

7.9

Crew

8.5

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
American Airlines
7.2
Good
10,000 reviews
Delta
8.0
Very good
7,985 reviews

Boarding

8.2

Overall

8.0

Entertainment

7.9

Comfort

7.9

Crew

8.5

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
Iberia
7.0
Good
2,884 reviews
Delta
8.0
Very good
7,985 reviews

Boarding

8.2

Overall

8.0

Entertainment

7.9

Comfort

7.9

Crew

8.5

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
British Airways
6.7
Okay
7,267 reviews
Delta
8.0
Very good
7,985 reviews

Boarding

8.2

Overall

8.0

Entertainment

7.9

Comfort

7.9

Crew

8.5

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.

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?

    Most people fly from Ontario (ONT) if they book a flight from Ontario to London. On average, Ontario has 0 outbound flights to London per day from 7 airlines. Ontario is conveniently located just 3.1 mi from Ontario’s city center.

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

    Flying on Delta is currently your cheapest option to London, with prices starting at $572. Additional round-trip tickets that might be worth considering are offered by KLM and Iberia, with the lowest prices starting at $580 and $582, respectively. You may be able to fly from Ontario to London for 29% less than the average price by searching for these airlines.

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

    The cheapest airlines for a one-way flight from Ontario to London are JetBlue ($374), British Airways ($382), and KLM ($403).

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

    The most popular flight routes from Ontario to London are Ontario - London Heathrow, Ontario - London Gatwick and Ontario - London City.

  • 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 vacation 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, November is the cheapest month in which you can book a flight from Ontario to London (average of $661). Flying from Ontario to London in June is currently the most expensive (average of $1,097). 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

Traveling to a place near London?

Book flights to London if you plan to visit one of these locations
Hounslow
Hayes
Thornton Heath
Harrow
Canterbury
Dartford
Dover
Orpington
Watford
Gatwick
Borehamwood
Aylesbury
Chelmsford
Southend-on-Sea
Folkestone
Chichester
Arundel
Eastbourne
Milton Keynes
Sutton

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Alternative routes for Ontario to London

See prices for flight routes from nearby airports that may be better suited for you.
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Top 7 airlines flying from Ontario to London

Discover the top 7 airlines that operate flights from Ontario to London. 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 2,558,603 searches. Data last updated August 16, 2025.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$572Average$711FlexibilityNo cancel feeOn-timeN/A
KLMCheapest$580Average$704FlexibilityNo cancel feeOn-time75%
IberiaCheapest$582Average$670FlexibilityNo cancel feeOn-time77%
Virgin AtlanticCheapest$629Average$889FlexibilityNo cancel feeOn-time72%
United AirlinesCheapest$633Average$784FlexibilityNo cancel feeOn-time69%
British AirwaysCheapest$648Average$862FlexibilityNo cancel feeOn-time70%
American AirlinesCheapest$648Average$947FlexibilityNo cancel feeOn-time71%

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