HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
London

$213+ 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 8/22. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LON
Jul 10 — Jul 171
Fri 7/10
Fri 7/17
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Ontario to London with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

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 June 10, 2026.

This United Airlines deal was found by Cheapflights users on 6/8. 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.
Tue 11/177:00 am
ONT
-
LHR
2 stops19h 50m
United Airlines
Thu 11/199:30 am
LHR
-
ONT
2 stops19h 51m
United Airlines
Deal found 6/8$754
This Ovago deal was found by Cheapflights users on 6/8. 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.
Tue 11/177:00 am
ONT
-
LHR
2 stops22h 00m
SWISS
Thu 11/1910:05 am
LHR
-
ONT
1 stop15h 42m
SWISS
Deal found 6/8$815
This Travelocity deal was found by Cheapflights users on 6/10. 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 Travelocity is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/162:22 pm
ONT
-
LHR
1 stop16h 03m
Multiple Airlines
Tue 10/1311:30 am
LHR
-
ONT
2 stops19h 36m
Multiple Airlines
Deal found 6/10$822
This Expedia deal was found by Cheapflights users on 6/6. 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.
Wed 10/712:35 pm
ONT
-
LHR
1 stop17h 50m
Iberia
Tue 10/1311:30 am
LHR
-
ONT
2 stops19h 36m
Iberia
Deal found 6/6$825
This Orbitz deal was found by Cheapflights users on 6/8. 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 10/71:52 pm
ONT
-
LHR
2 stops15h 28m
Multiple Airlines
Wed 10/144:25 pm
LHR
-
ONT
1 stop25h 04m
Multiple Airlines
Deal found 6/8$828
This Expedia deal was found by Cheapflights users on 6/8. 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 11/176:00 am
ONT
-
LHR
2 stops17h 10m
Multiple Airlines
Thu 11/199:55 am
LHR
-
ONT
1 stop19h 16m
Multiple Airlines
Deal found 6/8$831
This Gotogate deal was found by Cheapflights users on 6/8. 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 Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/146:00 am
ONT
-
LHR
2 stops20h 00m
Multiple Airlines
Thu 9/249:15 am
LHR
-
ONT
2 stops22h 21m
Multiple Airlines
Deal found 6/8$835
This Expedia deal was found by Cheapflights users on 6/6. 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 9/219:01 am
ONT
-
LHR
2 stops16h 34m
Multiple Airlines
Tue 9/294:25 pm
LHR
-
ONT
1 stop25h 04m
Multiple Airlines
Deal found 6/6$836
This Expedia deal was found by Cheapflights users on 6/5. 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.
Sat 9/52:43 pm
ONT
-
LHR
1 stop31h 37m
Multiple Airlines
Thu 9/104:10 pm
LHR
-
ONT
1 stop14h 33m
Multiple Airlines
Deal found 6/5$839
This Priceline deal was found by Cheapflights users on 6/10. 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.
Mon 10/51:31 pm
ONT
-
LHR
1 stop12h 59m
Multiple Airlines
Fri 10/165:00 pm
LHR
-
ONT
1 stop14h 42m
Multiple Airlines
Deal found 6/10$841
This Delta deal was found by Cheapflights users on 6/8. 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 10/67:00 am
ONT
-
LGW
2 stops18h 25m
Delta
Tue 10/1310:35 am
LGW
-
ONT
2 stops20h 08m
Delta
Deal found 6/8$878
This Delta deal was found by Cheapflights users on 6/8. 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 11/177:00 am
ONT
-
LCY
2 stops16h 15m
Delta
Thu 11/197:45 am
LCY
-
ONT
2 stops18h 33m
Delta
Deal found 6/8$896

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 June 10, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$754
(United Airlines)

One-way from

$213
(Kiwi.com)

Popular in

June

Cheapest in

March

Average price

$1,475
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 ($393 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 7% potential price decrease ($57 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in June 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 June 10, 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 11/4

12:00 pm-12:20 pm

1 stop16h 20m

London Heathrow

Tue 11/10

2:45 pm-10:54 pm

1 stop16h 09m

$877

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 10/6

8:00 am-11:35 am

2 stops19h 35m

London Heathrow

Thu 10/15

9:30 am-10:59 pm

2 stops21h 29m

$878

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 7/27

7:05 am-7:15 am

1 stop16h 10m

London Heathrow

Fri 8/21

1:25 pm-9:52 pm

1 stop16h 27m

$908

OntarioLondon

ONT - LCY

ONTLCY

Ontario

Wed 9/23

1:00 pm-4:40 pm

2 stops19h 40m

London City

Mon 9/28

9:20 am-10:40 pm

2 stops21h 20m

$944

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Thu 7/30

11:59 am-3:35 pm

1 stop19h 36m

London Heathrow

Mon 8/24

8:55 pm-4:24 pm

2 stops27h 29m

$945

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 7/22

6:01 pm-3:35 pm

1 stop13h 34m

London Heathrow

Wed 8/12

10:55 am-4:24 pm

1 stop13h 29m

$961

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Mon 9/21

12:25 pm-2:40 pm

2 stops18h 15m

London Gatwick

Tue 9/29

3:40 pm-10:00 pm

2 stops38h 20m

$1,006

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 7/20

1:18 pm-9:40 am

1 stop12h 22m

London Heathrow

Tue 7/28

4:15 pm-10:37 pm

1 stop14h 22m

$1,042

OntarioLondon

ONT - LGW

ONTLGW

Ontario

Tue 9/8

3:14 pm-2:40 pm

2 stops15h 26m

London Gatwick

Tue 9/15

3:40 pm-10:00 pm

2 stops38h 20m

$1,076

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Mon 7/27

1:00 pm-10:00 am

1 stop13h 00m

London Heathrow

Wed 8/12

10:55 am-4:24 pm

1 stop13h 29m

$1,078

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/9

Showing 1-10 of 60 resultsSorted by cheapest first
1
2
3
...
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 June.
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 June is currently the most expensive (average of $1,105). 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 June 10, 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
8,395 reviews

Boarding

8.1

Comfort

7.8

Food

7.2

Entertainment

7.8

Overall

7.9

Crew

8.5

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
8,395 reviews
Delta
7.9
Good
8,395 reviews

Boarding

8.1

Comfort

7.8

Food

7.2

Entertainment

7.8

Overall

7.9

Crew

8.5

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
9,804 reviews
Delta
7.9
Good
8,395 reviews

Boarding

8.1

Comfort

7.8

Food

7.2

Entertainment

7.8

Overall

7.9

Crew

8.5

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
8,035 reviews
Delta
7.9
Good
8,395 reviews

Boarding

8.1

Comfort

7.8

Food

7.2

Entertainment

7.8

Overall

7.9

Crew

8.5

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?

    United Airlines, SWISS, and Iberia can get you from Ontario to London in just under 17h 50m. Your travel time can differ by up to 4h 10m. 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 $570. 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 33% 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 June is currently the most expensive (average of $1,105). 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
Wembley
Harrow
Eastleigh
Dartford
Dover
Orpington
Watford
Chipping Norton
Hayes
Kingston upon Thames
Eastbourne
Slough
Stansted

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 June 10, 2026.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$570Average$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$972FlexibilityNo cancel feeOn-time69%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.
Site
©2026 Cheapflights