HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
London

$276+ 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 8/14. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LON
jul. 6 — jul. 131
dom. 7/6
dom. 7/13
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.

Cheapflights Tip: The best prices from Ontario to London are usually found in September or October, booked 79 days in advance, depart on a Wednesday or Tuesday and return on a Tuesday

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 julio 1, 2025.

Round-trip from

$496
(Delta)

One-way from

$276
(Kiwi.com)

Popular in

June

Cheapest in

September

Average price

$730
From Ontario to London (LON)
Search Deals
One-way flight from Ontario to London (LON)
Search Deals
Highest demand for flights based on searches. 9% potential increase in price ($78 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease ($33 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in July 2025
Search Deals

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 julio 1, 2025.

This Delta deal was found by Cheapflights users on 6/29. 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.
lun. 8/257:05 amONT - LGW
2 stops18h 55mDelta
vie. 9/512:00 pmLGW - ONT
2 stops28h 55mDelta
Deal found 6/29$496
This Rumbo deal was found by Cheapflights users on 6/29. 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 Rumbo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 8/137:05 amONT - LHR
1 stop15h 40mVirgin Atlantic
mié. 8/2011:00 amLHR - ONT
1 stop20h 40mVirgin Atlantic
Deal found 6/29$521
This Delta deal was found by Cheapflights users on 6/29. 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.
mié. 8/139:50 amONT - LHR
1 stop16h 00mDelta
mié. 8/209:00 amLHR - ONT
2 stops21h 20mDelta
Deal found 6/29$526
This KLM deal was found by Cheapflights users on 6/30. 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.
mar. 9/1612:00 pmONT - LHR
1 stop15h 10mKLM
jue. 9/251:05 pmLHR - ONT
1 stop17h 18mKLM
Deal found 6/30$573
This United Airlines deal was found by Cheapflights users on 6/30. 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.
dom. 8/31:34 pmONT - LHR
1 stop12h 06mUnited Airlines
mar. 8/192:50 pmLHR - ONT
1 stop13h 53mUnited Airlines
Deal found 6/30$656
This American Airlines deal was found by Cheapflights users on 6/30. 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.
jue. 8/146:17 amONT - LGW
2 stops17h 53mAmerican Airlines
jue. 8/2110:25 amLGW - ONT
2 stops19h 14mAmerican Airlines
Deal found 6/30$675
This Trip.com deal was found by Cheapflights users on 6/29. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
dom. 9/1412:45 pmONT - LHR
1 stop14h 05mIberia
jue. 9/2512:00 pmLHR - ONT
1 stop14h 54mIberia
Deal found 6/29$686
This United Airlines deal was found by Cheapflights users on 6/30. 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.
mar. 8/127:00 amONT - LCY
2 stops21h 30mMultiple Airlines
mar. 8/199:25 amLCY - ONT
2 stops19h 08mMultiple Airlines
Deal found 6/30$690
This Priceline deal was found by Cheapflights users on 6/30. 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.
mar. 9/1610:53 amONT - LHR
1 stop14h 07mBritish Airways
vie. 9/268:20 amLHR - ONT
1 stop22h 13mBritish Airways
Deal found 6/30$738
This Air France deal was found by Cheapflights users on 6/29. 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 Air France is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
lun. 8/257:05 amONT - LGW
2 stops18h 55mKLM
lun. 9/112:00 pmLGW - ONT
2 stops39h 11mKLM
Deal found 6/29$891
This lol.travel deal was found by Cheapflights users on 7/1. 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 lol.travel is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 8/142:31 pmONT - LGW
2 stops36h 24mIberia
vie. 8/298:40 pmLGW - ONT
2 stops34h 08mIberia
Deal found 7/1$914
This Icelandair deal was found by Cheapflights users on 6/30. 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.
mar. 8/122:45 pmONT - LGW
2 stops15h 55mMultiple Airlines
mar. 8/191:00 pmLGW - ONT
2 stops17h 05mMultiple Airlines
Deal found 6/30$986

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 julio 1, 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 - LGW

ONTLGW

Ontario

lun. 8/25

7:05 am-10:00 am

2 stops18h 55m

London Gatwick

vie. 9/5

12:00 pm-8:55 am

2 stops28h 55m

$496

OntarioLondon

ONT - LHR

ONTLHR

Ontario

mié. 8/13

7:05 am-6:45 am

1 stop15h 40m

London Heathrow

mié. 8/20

11:00 am-11:40 pm

1 stop20h 40m

$521

OntarioLondon

ONT - LHR

ONTLHR

Ontario

mié. 8/13

9:50 am-9:50 am

1 stop16h 00m

London Heathrow

mié. 8/20

9:00 am-10:20 pm

2 stops21h 20m

$526

OntarioLondon

ONT - LHR

ONTLHR

Ontario

mar. 11/18

12:00 pm-10:35 am

1 stop14h 35m

London Heathrow

mié. 11/26

2:20 pm-10:41 pm

1 stop16h 21m

$534

OntarioLondon

ONT - LCY

ONTLCY

Ontario

mié. 10/1

4:40 pm-4:40 pm

2 stops16h 00m

London City

mié. 10/8

10:00 am-10:41 pm

2 stops20h 41m

$585

OntarioLondon

ONT - LHR

ONTLHR

Ontario

dom. 8/3

1:34 pm-9:40 am

1 stop12h 06m

London Heathrow

mar. 8/19

2:50 pm-8:43 pm

1 stop13h 53m

$656

OntarioLondon

ONT - LGW

ONTLGW

Ontario

jue. 8/14

6:17 am-8:10 am

2 stops17h 53m

London Gatwick

jue. 8/21

10:25 am-9:39 pm

2 stops19h 14m

$675

OntarioLondon

ONT - LHR

ONTLHR

Ontario

dom. 9/14

12:45 pm-10:50 am

1 stop14h 05m

London Heathrow

jue. 9/25

12:00 pm-6:54 pm

1 stop14h 54m

$686

OntarioLondon

ONT - LCY

ONTLCY

Ontario

mar. 8/12

7:00 am-12:30 pm

2 stops21h 30m

London City

mar. 8/19

9:25 am-8:33 pm

2 stops19h 08m

$690

OntarioLondon

ONT - LHR

ONTLHR

Ontario

mar. 9/16

1:10 pm-2:40 pm

1 stop17h 30m

London Heathrow

vie. 9/26

11:00 am-9:24 pm

1 stop18h 24m

$738

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/30

Showing 1-10 of 37 results
1
2
3
4

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

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

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

To ensure you get the cheapest price possible for a flight from Ontario to London, you should look to book at least 78 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 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 $1,098). 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 julio 1, 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.

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 julio 1, 2025.
Get a feel of what it's like to fly with Delta, KLM, and United 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
7,973 reviews

Crew

8.5

Entertainment

7.9

Boarding

8.2

Food

7.3

Comfort

7.9

Overall

8.0

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
7,973 reviews
Delta
8.0
Very good
7,973 reviews

Crew

8.5

Entertainment

7.9

Boarding

8.2

Food

7.3

Comfort

7.9

Overall

8.0

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.
KLM
7.8
Good
1,366 reviews
Delta
8.0
Very good
7,973 reviews

Crew

8.5

Entertainment

7.9

Boarding

8.2

Food

7.3

Comfort

7.9

Overall

8.0

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
8,858 reviews
Delta
8.0
Very good
7,973 reviews

Crew

8.5

Entertainment

7.9

Boarding

8.2

Food

7.3

Comfort

7.9

Overall

8.0

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.
Virgin Atlantic
7.4
Good
654 reviews
Delta
8.0
Very good
7,973 reviews

Crew

8.5

Entertainment

7.9

Boarding

8.2

Food

7.3

Comfort

7.9

Overall

8.0

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.
JetBlue
7.3
Good
2,919 reviews
Delta
8.0
Very good
7,973 reviews

Crew

8.5

Entertainment

7.9

Boarding

8.2

Food

7.3

Comfort

7.9

Overall

8.0

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 $496. Additional round-trip tickets that might be worth considering are offered by Virgin Atlantic and KLM, with the lowest prices starting at $521 and $534, respectively. You may be able to fly from Ontario to London for 36% 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 ($381), British Airways ($397), and United Airlines ($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 $1,098). 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 Ontario?

Book flights to Ontario if you plan to visit one of these locations
Hounslow
Hayes
Thornton Heath
Canterbury
Harrow
Dover
Gatwick
Orpington
Watford
Croydon
Folkestone
Borehamwood
Aylesbury
Chelmsford
Brentwood
Chichester
Arundel
Milton Keynes
Bishop's Stortford
Dartford

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.

Alternative routes for Ontario to London

See prices for flight routes from nearby airports that may be better suited for you.
Los Angeles to Heathrow flights
San Francisco to Heathrow flights
Los Angeles to London City flights
Los Angeles to Gatwick flights
San Francisco to Gatwick flights
San Francisco to London City flights
Los Angeles to Luton flights
San Diego to Heathrow flights
Ontario to Heathrow flights
Los Angeles to Stansted flights
San Francisco to Stansted flights
San Francisco to Luton flights
Las Vegas to Heathrow flights
San Diego to Gatwick flights
Los Angeles to Edinburgh flights
San Jose to Heathrow flights
San Diego to London City flights
San Francisco to Edinburgh flights
Palm Springs to Heathrow flights
Los Angeles to Southend flights
Los Angeles to Manchester flights
Sacramento to Heathrow flights
Santa Ana to Heathrow flights
Oakland to Heathrow flights
Las Vegas to London City flights
Reno to Heathrow flights
Las Vegas to Gatwick flights
Los Angeles to Southampton flights
San Francisco to Manchester flights
San Jose to Gatwick flights
Ontario to Manchester flights
Sacramento to Gatwick flights
Oakland to Gatwick flights
Long Beach to Heathrow flights
Santa Ana to Manchester flights
San Jose to London City flights
Burbank to Heathrow flights
Ontario to Edinburgh flights
Sacramento to London City flights
Las Vegas to Edinburgh flights
Reno to Gatwick flights
Fresno to Heathrow flights
Santa Ana to Gatwick flights
San Francisco to Southampton flights
San Jose to Edinburgh flights
San Diego to Edinburgh flights
Las Vegas to Luton flights
Sacramento to Edinburgh flights
Burbank to Manchester flights
San Francisco to Birmingham flights

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 julio 1, 2025.
AirlineCheapestAverageFlexibilityOn-time
IberiaCheapest$582Average$670FlexibilityNo cancel feeOn-time77%
KLMCheapest$608Average$763FlexibilityNo cancel feeOn-time75%
DeltaCheapest$613Average$796FlexibilityNo cancel feeOn-timeN/A
Virgin AtlanticCheapest$629Average$889FlexibilityNo cancel feeOn-time72%
United AirlinesCheapest$633Average$785FlexibilityNo cancel feeOn-time69%
British AirwaysCheapest$648Average$862FlexibilityNo cancel feeOn-time70%
American AirlinesCheapest$648Average$907FlexibilityNo cancel feeOn-time71%

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.