Find flights
When to book
Airlines
FAQs

Cheap flights from Ontario to London Heathrow Airport from £237

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 1/10. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LHR
18 Jun — 25 Jun1
1 adult

Cheap flight deals from Ontario to Heathrow

Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to Heathrow (LHR). 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 13 June 2025.

Round-trip from

£385

One-way from

£237

Popular in

June

Cheapest in

March

Average price

£969
Delta
  • Delta
  • 15/10-11/11
  • 3 total stops
  • 34h 48m total
  • Ontario to London
Search Deals
1/10
  • 1/10
  • 2 total stops
  • 26h 56m total
  • Ontario to London
Search Deals
Highest demand for flights based on searches. 23% potential increase in price (£140 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease (£24 potential savings vs. average return price).
Search Deals
Average for round-trip flights in June 2025
Search Deals

Find flight deals from Ontario to Heathrow

Cheapest flights from Ontario to Heathrow
Explore the most affordable flight options available from Ontario to Heathrow. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 13 June 2025.

Wed 15/1011:29ONT - LHR
1 stop15h 51mDelta
Tue 11/1106:20LHR - ONT
2 stops18h 57mDelta
Deal found 13/6£385
Tue 21/1013:00ONT - LHR
1 stop12h 50mKLM
Wed 29/1009:20LHR - ONT
1 stop17h 22mKLM
Deal found 12/6£391
Tue 9/1217:09ONT - LHR
1 stop12h 11mBritish Airways
Tue 16/1214:55LHR - ONT
1 stop15h 03mBritish Airways
Deal found 12/6£467
Sun 3/813:34ONT - LHR
1 stop14h 46mUnited Airlines
Tue 19/814:50LHR - ONT
1 stop13h 53mUnited Airlines
Deal found 12/6£478
Sun 5/1014:30ONT - LHR
1 stop15h 55mIberia
Tue 14/1006:10LHR - ONT
2 stops25h 52mIberia
Deal found 11/6£484
Sun 27/711:40ONT - LHR
1 stop17h 50mMultiple Airlines
Sun 3/813:25LHR - ONT
1 stop17h 22mMultiple Airlines
Deal found 12/6£489
Sun 3/816:45ONT - LHR
1 stop12h 05mAmerican Airlines
Tue 19/811:15LHR - ONT
1 stop14h 37mAmerican Airlines
Deal found 11/6£495
Thu 17/711:40ONT - LHR
1 stop17h 50mVirgin Atlantic
Thu 24/709:40LHR - ONT
2 stops22h 02mVirgin Atlantic
Deal found 11/6£496
Sun 5/1022:56ONT - LHR
1 stop13h 49mJetBlue
Fri 10/1008:15LHR - ONT
1 stop21h 14mJetBlue
Deal found 12/6£553
Sat 6/905:10ONT - LHR
2 stops17h 20mAir Canada
Sat 13/914:05LHR - ONT
2 stops59h 24mAir Canada
Deal found 11/6£568

Cheapflights Fare Finder

Customise your flight search to find flights from Ontario to Heathrow 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 13 June 2025.
Use the filters below to find and compare flights from Ontario to London Heathrow Airport that are best for you.

Fly from

Ontario

Fly to

Heathrow

Route

Depart

Return

Price

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Wed 15/10

11:29-11:20

1 stop15h 51m

London Heathrow

Tue 11/11

06:20-17:17

2 stops18h 57m

£385

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 21/10

13:00-09:50

1 stop12h 50m

London Heathrow

Wed 29/10

09:20-19:42

1 stop17h 22m

£391

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Tue 9/12

17:09-13:20

1 stop12h 11m

London Heathrow

Tue 16/12

14:55-21:58

1 stop15h 03m

£467

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 3/8

13:34-12:20

1 stop14h 46m

London Heathrow

Tue 19/8

14:50-20:43

1 stop13h 53m

£478

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 5/10

14:30-14:25

1 stop15h 55m

London Heathrow

Tue 14/10

06:10-00:02

2 stops25h 52m

£484

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 27/7

11:40-13:30

1 stop17h 50m

London Heathrow

Sun 3/8

13:25-22:47

1 stop17h 22m

£489

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 3/8

16:45-12:50

1 stop12h 05m

London Heathrow

Tue 19/8

11:15-17:52

1 stop14h 37m

£495

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Thu 17/7

11:40-13:30

1 stop17h 50m

London Heathrow

Thu 24/7

09:40-23:42

2 stops22h 02m

£496

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sun 5/10

22:56-20:45

1 stop13h 49m

London Heathrow

Fri 10/10

08:15-21:29

1 stop21h 14m

£553

OntarioLondon

ONT - LHR

ONTLHR

Ontario

Sat 6/9

05:10-06:30

2 stops17h 20m

London Heathrow

Sat 13/9

14:05-17:29

2 stops59h 24m

£568

Flights are sorted by cheapest return flights first.

Deals found on 11/6

Showing 1-10 of 21 results
1
2
3

Best time to book a flight from Ontario to Heathrow

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

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

Use this chart to determine the optimal time to book a return flight from Ontario to Heathrow. Price data was last updated on 9 June 2025.

To ensure you get the cheapest price possible for a flight from Ontario to London Heathrow Airport, you should look to book at least 52 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 Heathrow Airport?

Currently, January is the cheapest month in which you can book a flight from Ontario to London Heathrow Airport (average of £112). Flying from Ontario to London Heathrow Airport in August is currently the most expensive (average of £164). 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 LHR?

Find hourly flight availability from Ontario to Heathrow. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 13 June 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Ontario to London Heathrow Airport as you normally would.

Rainfall in Heathrow by month

Plan your trip to Heathrow by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in London Heathrow Airport ranges from 40.0 - 70.0 inches per month. January is typically the wettest month, when rainfall can reach 70.0 mm. July is typically the driest time to visit London Heathrow Airport when rainfall is around 40.0 mm.

Temperature in Heathrow by month

Plan your trip to Heathrow by taking into account the average temperature totals by month.

If weather is an important factor for your trip to London Heathrow Airport, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 17.0 C. Travellers hoping to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 4.0 C).

Reviews of airlines servicing Heathrow

Get insights into the airlines that provide service to Heathrow. 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 Heathrow. Reviews last updated 13 June 2025.
Read reviews from past customers who have flown Delta, KLM and United Airlines from Ontario to London. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
8.0
Very Good
7,946 reviews
Check prices

Entertainment

7.9

Overall

8.0

Boarding

8.2

Food

7.3

Crew

8.5

Comfort

7.9

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
7,946 reviews
Delta
8.0
Very Good
7,946 reviews
Check prices

Entertainment

7.9

Overall

8.0

Boarding

8.2

Food

7.3

Crew

8.5

Comfort

7.9

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
1,358 reviews
Delta
8.0
Very Good
7,946 reviews
Check prices

Entertainment

7.9

Overall

8.0

Boarding

8.2

Food

7.3

Crew

8.5

Comfort

7.9

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
8,790 reviews
Delta
8.0
Very Good
7,946 reviews
Check prices

Entertainment

7.9

Overall

8.0

Boarding

8.2

Food

7.3

Crew

8.5

Comfort

7.9

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
652 reviews
Delta
8.0
Very Good
7,946 reviews
Check prices

Entertainment

7.9

Overall

8.0

Boarding

8.2

Food

7.3

Crew

8.5

Comfort

7.9

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
2,923 reviews
Delta
8.0
Very Good
7,946 reviews
Check prices

Entertainment

7.9

Overall

8.0

Boarding

8.2

Food

7.3

Crew

8.5

Comfort

7.9

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 Heathrow. 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 Heathrow?

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

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

    Cheapflights users have booked flights from Ontario to London Heathrow Airport round-trip from £385. Other airlines that can offer you cheap pricing are KLM, from £391, and British Airways, from £467. Delta is currently priced 37% below the average price you’ll pay for this route.

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

    For one-way options, check prices for JetBlue. According to our data, you can fly for as low as £290. Users have also found prices from £294 and £295 on United Airlines and Air Canada, respectively.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Ontario to Heathrow 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 Heathrow Airport?

    Currently, January is the cheapest month in which you can book a flight from Ontario to London Heathrow Airport (average of £112). Flying from Ontario to London Heathrow Airport in August is currently the most expensive (average of £164). 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

Travelling to a place near Ontario?

Book flights to Ontario if you plan to visit one of these locations
Deal
Hounslow
Croydon
Milton Keynes
Northampton
Gatwick
Luton
Slough
Wembley
Crawley
Eastbourne
Ilford
Southend-on-Sea
Watford
Hayes
Ipswich
Winchester
Folkestone
Maidstone
Swindon

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 Heathrow

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
San Diego to Heathrow flights
Los Angeles to Luton flights
Los Angeles to Stansted flights
Las Vegas to Heathrow flights
San Francisco to Luton flights
San Francisco to Stansted flights
San Jose to Heathrow flights
San Diego to Gatwick flights
Oakland to Heathrow flights
Los Angeles to Southend flights
Las Vegas to Gatwick flights
Sacramento to Heathrow flights
Las Vegas to London City flights
San Jose to Gatwick flights
Santa Ana to Heathrow flights
Oakland to Gatwick flights
Sacramento to Gatwick flights
Reno to Heathrow flights
Burbank to Heathrow flights
Palm Springs to Heathrow flights
Reno to Gatwick flights
Ontario to Gatwick flights
Las Vegas to Luton flights
Santa Ana to Gatwick flights
San Diego to Stansted flights
Medford to Heathrow flights
Tijuana to Heathrow flights
San Jose to Stansted 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 Ontario to Heathrow?

When you search for this flight from Ontario to Heathrow, 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 Ontario to Heathrow?

It’s simple! Cheapflights, which is free to use for everyone, saves millions of users time and money every year by helping them find the cheapest and most suitable flights from Ontario to Heathrow.

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

Certainly. Search results for flights to Heathrow from Ontario shown to you on Cheapflights can be narrowed down with different useful search filters, which includes flexible booking options.

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

Yes, and it’s super simple to set up. Click the bell icon next to the flight deals above and provide a valid email address to enable Price Alerts. That’s it!

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
©2025 Cheapflights