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$320+ 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 8/25. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LON
Jun 27 — Jul 41
Sat 6/27
Sat 7/4
1 adult, Economy
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Find cheap flights from Ontario to London with Cheapflights

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Cheap 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 May 28, 2026.

This CheapOair deal was found by Cheapflights users on 5/24. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/257:06 am
ONT
-
LHR
2 stops20h 54m
Multiple Airlines
Thu 8/2712:00 pm
LHR
-
ONT
1 stop18h 04m
Multiple Airlines
Deal found 5/24$783
This Ovago deal was found by Cheapflights users on 5/27. 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 Ovago is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/191:56 pm
ONT
-
LHR
1 stop33h 29m
SWISS
Tue 9/226:00 am
LHR
-
ONT
2 stops21h 57m
SWISS
Deal found 5/27$794
This Expedia deal was found by Cheapflights users on 5/27. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/104:47 pm
ONT
-
LHR
1 stop12h 28m
British Airways
Tue 11/173:00 pm
LHR
-
ONT
1 stop15h 23m
British Airways
Deal found 5/27$854
This Expedia deal was found by Cheapflights users on 5/25. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/1412:35 pm
ONT
-
LHR
1 stop16h 15m
Multiple Airlines
Mon 9/287:30 pm
LHR
-
ONT
2 stops34h 28m
Multiple Airlines
Deal found 5/25$858
This Expedia deal was found by Cheapflights users on 5/26. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/32:59 pm
ONT
-
LHR
1 stop13h 01m
British Airways
Tue 11/103:00 pm
LHR
-
ONT
1 stop15h 23m
British Airways
Deal found 5/26$862
This Priceline deal was found by Cheapflights users on 5/28. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/202:22 pm
ONT
-
LHR
1 stop14h 28m
British Airways
Tue 9/294:25 pm
LHR
-
ONT
1 stop25h 04m
British Airways
Deal found 5/28$863
This Orbitz deal was found by Cheapflights users on 5/27. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/2612:59 pm
ONT
-
LHR
1 stop13h 51m
British Airways
Mon 9/72:25 pm
LHR
-
ONT
1 stop14h 47m
British Airways
Deal found 5/27$864
This Iberia deal was found by Cheapflights users on 5/26. 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 11/36:10 am
ONT
-
LHR
1 stop19h 50m
Iberia
Tue 11/106:00 am
LHR
-
ONT
2 stops24h 23m
Iberia
Deal found 5/26$866
This Delta deal was found by Cheapflights users on 5/28. 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 8/266:01 pm
ONT
-
LHR
1 stop13h 34m
Delta
Fri 9/46:30 am
LHR
-
ONT
2 stops25h 04m
Delta
Deal found 5/28$867
This Delta deal was found by Cheapflights users on 5/28. 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 8/2612:00 pm
ONT
-
LHR
1 stop15h 20m
Delta
Wed 9/211:45 am
LHR
-
ONT
2 stops18h 38m
Delta
Deal found 5/28$868
This United Airlines deal was found by Cheapflights users on 5/28. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/277:00 am
ONT
-
LHR
2 stops16h 55m
United Airlines
Sat 8/297:45 am
LHR
-
ONT
2 stops20h 16m
United Airlines
Deal found 5/28$870
This Delta deal was found by Cheapflights users on 5/26. 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 11/37:00 am
ONT
-
LHR
2 stops18h 20m
Delta
Tue 11/106:30 am
LHR
-
ONT
2 stops18h 47m
Delta
Deal found 5/26$871

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 May 28, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$783
(CheapOair)

One-way from

$320
(Cheapflightsfares)

Popular in

June

Cheapest in

March

Average price

$1,054
Provider with most accurate pricing for Ontario-London (LON) flight deals.
Search Deals
Provider most trusted by Cheapflights users for Ontario-London (LON) flights.
Search Deals
From Ontario to London (LON)
Search Deals
One-way flight from Ontario to London (LON)
Search Deals
Highest demand for flights based on searches. 31% potential increase in price ($379 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 6% potential price decrease ($54 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in May 2026
Search Deals

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 May 28, 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 round-trip

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 10/14

2:14 pm-3:05 pm

1 stop16h 51m

London Heathrow

Thu 10/22

5:00 pm-11:42 pm

1 stop14h 42m

$877

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 8/26

6:01 pm-3:35 pm

1 stop13h 34m

London Heathrow

Thu 9/10

9:20 am-6:01 pm

1 stop16h 41m

$895

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 9/9

1:00 pm-10:00 am

1 stop13h 00m

London Heathrow

Wed 9/30

10:55 am-4:33 pm

1 stop13h 38m

$896

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 8/3

12:04 pm-3:05 pm

1 stop19h 01m

London Heathrow

Thu 8/20

5:00 pm-11:24 pm

1 stop14h 24m

$923

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 8/3

2:15 pm-2:25 pm

1 stop16h 10m

London Heathrow

Thu 8/20

8:55 am-6:47 pm

1 stop17h 52m

$924

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Fri 9/18

12:12 pm-3:05 pm

1 stop18h 53m

London Heathrow

Fri 10/2

5:00 pm-11:24 pm

1 stop14h 24m

$927

OntarioLondon

ONT - LCY

ONTLCY

Ontario

Wed 9/23

1:00 pm-4:40 pm

2 stops19h 40m

London City

Mon 9/28

10:00 am-10:40 pm

2 stops20h 40m

$946

OntarioLondon

ONT - LCY

ONTLCY

Ontario

Thu 10/8

1:00 pm-4:40 pm

2 stops19h 40m

London City

Thu 10/15

9:20 am-10:43 pm

2 stops21h 23m

$946

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Fri 10/9

9:55 am-1:05 pm

2 stops19h 10m

London Heathrow

Sat 10/17

6:30 am-5:17 pm

2 stops18h 47m

$971

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 8/16

5:26 pm-3:05 pm

1 stop13h 39m

London Heathrow

Mon 8/24

5:00 pm-11:24 pm

1 stop14h 24m

$973

Flights are sorted by cheapest round-trip flights first.

Deals found on 5/26

Showing 1-10 of 60 resultsSorted by cheapest first
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2
3
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6

Compare providers for flights from Ontario to London

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Ontario to London in May.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
OvagoPrice Accuracy3 starsTrust Score*3 stars
AranGrantPrice Accuracy3 starsTrust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Ontario-London flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ontario-London flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ontario-London flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Ontario-London flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Ontario-London flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

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, September is the cheapest month in which you can book a flight from Ontario to London (average of $251). Flying from Ontario to London in July is currently the most expensive (average of $721). 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 to fly round-trip from Ontario to London?

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 May 28, 2026.
Get a feel of what it's like to fly with Delta,United Airlines, andBritish Airways 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
7.9
Good
8,422 reviews

Overall

7.9

Crew

8.5

Entertainment

7.8

Boarding

8.1

Food

7.2

Comfort

7.8

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
7.9
Good
8,422 reviews
Delta
7.9
Good
8,422 reviews

Overall

7.9

Crew

8.5

Entertainment

7.8

Boarding

8.1

Food

7.2

Comfort

7.8

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
9,757 reviews
Delta
7.9
Good
8,422 reviews

Overall

7.9

Crew

8.5

Entertainment

7.8

Boarding

8.1

Food

7.2

Comfort

7.8

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
8,008 reviews
Delta
7.9
Good
8,422 reviews

Overall

7.9

Crew

8.5

Entertainment

7.8

Boarding

8.1

Food

7.2

Comfort

7.8

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 5 airlines. Ontario is conveniently located just 3.1 mi from Ontario’s city center.

  • How long is the flight from Ontario to London?

    Alaska Airlines, Delta, and United Airlines can get you from Ontario to London in just under 13h 34m. Your travel time can differ by up to 3h 17m. Airlines will cover a distance of 5407 mi. This flight may include one or multiple stops.

  • 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 American Airlines, with the lowest prices starting at $580 and $620, respectively. You may be able to fly from Ontario to London for 31% less than the average price by searching for these airlines.

  • 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, September is the cheapest month in which you can book a flight from Ontario to London (average of $251). Flying from Ontario to London in July is currently the most expensive (average of $721). 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
Ilford
Dorking
Hounslow
Winchester
Croydon
Gatwick
Southend-on-Sea
Harrow
Eastleigh
Dartford
Dover
Orpington
Watford
Chipping Norton
Hayes
Kingston upon Thames
Eastbourne
Slough
Stansted
Sutton

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Top 5 airlines flying from Ontario to London

Discover the top 5 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 May 28, 2026.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$572Average$672FlexibilityNo cancel feeOn-timeN/A
KLMCheapest$580Average$672FlexibilityNo cancel feeOn-time75%
American AirlinesCheapest$620Average$650FlexibilityNo cancel feeOn-time71%
British AirwaysCheapest$624Average$871FlexibilityNo cancel feeOn-time70%
United AirlinesCheapest$662Average$941FlexibilityNo cancel feeOn-time69%

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