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Cheap flights from Ontario to London from £237

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Ontario to London departing on 1/12. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
1 adult, Economy, 0 bags

Find the cheapest flights from Ontario to London

Cheap return flights

Enter your travel dates to find the best prices.
United Airlines Logo
13:35 - 07:25ONT  Ontario-LHR London Heathrow
33h 50m1 stop San Francisco
United Airlines Logo
06:50 - 18:47LHR  London Heathrow-ONT Ontario
19h 57m2 stops Brussels Bruxelles-National Chicago O'Hare Intl
£547United Airlines
Sun, 1 Nov - Wed, 4 Nov
United Airlines Logo
18:37 - 07:25ONT  Ontario-LHR London Heathrow
28h 48m1 stop San Francisco
United Airlines Logo
06:50 - 18:47LHR  London Heathrow-ONT Ontario
19h 57m2 stops Brussels Bruxelles-National Chicago O'Hare Intl
£547United Airlines
Mon, 9 Nov - Thu, 12 Nov
United Airlines Logo
06:00 - 09:40ONT  Ontario-LHR London Heathrow
43h 40m2 stops San Francisco Denver Intl
United Airlines Logo
06:50 - 18:47LHR  London Heathrow-ONT Ontario
19h 57m2 stops Brussels Bruxelles-National Chicago O'Hare Intl
£554United Airlines
Mon, 9 Nov - Thu, 12 Nov
United Airlines Logo
13:29 - 07:40ONT  Ontario-LHR London Heathrow
34h 11m2 stops Denver Intl Houston George Bush Intcntl
United Airlines Logo
06:50 - 18:47LHR  London Heathrow-ONT Ontario
19h 57m2 stops Brussels Bruxelles-National Chicago O'Hare Intl
£558United Airlines
Sun, 1 Nov - Wed, 4 Nov
Multiple Airlines Logo
05:00 - 11:50ONT  Ontario-LHR London Heathrow
22h 50m2 stops Denver Intl Vancouver Intl
Multiple Airlines Logo
14:45 - 22:39LHR  London Heathrow-ONT Ontario
15h 54m1 stop Seattle/Tacoma Intl
£593Multiple Airlines
Sun, 10 Jan - Sun, 24 Jan
Alaska Airlines Logo
06:00 - 12:20ONT  Ontario-LHR London Heathrow
22h 20m1 stop Seattle/Tacoma Intl
Alaska Airlines Logo
14:45 - 22:39LHR  London Heathrow-ONT Ontario
15h 54m1 stop Seattle/Tacoma Intl
£596Alaska Airlines
Sun, 17 Jan - Mon, 25 Jan
Alaska Airlines Logo
12:00 - 12:20ONT  Ontario-LHR London Heathrow
16h 20m1 stop Seattle/Tacoma Intl
Alaska Airlines Logo
14:45 - 22:39LHR  London Heathrow-ONT Ontario
15h 54m1 stop Seattle/Tacoma Intl
£596Alaska Airlines
Tue, 8 Dec - Tue, 15 Dec
Alaska Airlines Logo
06:00 - 12:20ONT  Ontario-LHR London Heathrow
22h 20m1 stop Seattle/Tacoma Intl
Alaska Airlines Logo
14:45 - 22:39LHR  London Heathrow-ONT Ontario
15h 54m1 stop Seattle/Tacoma Intl
£596Alaska Airlines
Wed, 2 Dec - Wed, 9 Dec
Multiple Airlines Logo
15:09 - 12:00ONT  Ontario-LHR London Heathrow
12h 51m1 stop Dallas/Fort Worth
Multiple Airlines Logo
14:45 - 22:39LHR  London Heathrow-ONT Ontario
15h 54m1 stop Seattle/Tacoma Intl
£596Multiple Airlines
Tue, 26 Jan - Sun, 31 Jan
Multiple Airlines Logo
12:46 - 10:00ONT  Ontario-LHR London Heathrow
13h 14m1 stop Dallas/Fort Worth
Multiple Airlines Logo
14:45 - 22:39LHR  London Heathrow-ONT Ontario
15h 54m1 stop Seattle/Tacoma Intl
£596Multiple Airlines
Wed, 9 Dec - Wed, 16 Dec

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Delta flights from Ontario to London Heathrow Airport

Our best Delta deals on Ontario to London Heathrow Airport flight tickets
Delta
2 Nov
ONT06:20Ontario
20h 20m
1 stop
LHR10:40London Heathrow
26 Nov
LHR06:30London Heathrow
21h 11m
2 stops
ONT19:41Ontario
£643
Delta
1 Nov
ONT07:07Ontario
16h 38m
2 stops
LHR07:45London Heathrow
26 Nov
LHR06:30London Heathrow
18h 43m
2 stops
ONT17:13Ontario
£646
Delta
13 Aug
ONT06:00Ontario
17h 15m
2 stops
LHR07:15London Heathrow
20 Aug
LHR06:30London Heathrow
23h 22m
2 stops
ONT21:52Ontario
£827

Air Canada flights from Ontario to London Heathrow Airport

Our best Air Canada deals on Ontario to London Heathrow Airport flight tickets
Air Canada
31 Oct
ONT13:29Ontario
36h 51m
2 stops
LHR09:20London Heathrow
24 Nov
LHR13:25London Heathrow
39h 26m
2 stops
ONT20:51Ontario
£648
Air Canada
2 Nov
ONT05:00Ontario
18h 10m
2 stops
LHR07:10London Heathrow
25 Nov
LHR13:25London Heathrow
31h 08m
2 stops
ONT12:33Ontario
£650
Air Canada
31 Oct
ONT13:29Ontario
36h 51m
2 stops
LHR09:20London Heathrow
26 Nov
LHR18:00London Heathrow
34h 51m
2 stops
ONT20:51Ontario
£654

momondo Fare Finder

 
Customise your flight search to find flights from Ontario to London Heathrow Airport 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, momondo users made 279,928 searches. Data last updated 6 August 2026.
Use the filters below to find and compare flights from Ontario to London Heathrow Airport that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest return flight

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Sun 1/11

13:35-07:25

1 stop33h 50m

London Heathrow

Wed 4/11

06:50-18:47

2 stops19h 57m

£547

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Mon 9/11

18:37-07:25

1 stop28h 48m

London Heathrow

Thu 12/11

06:50-18:47

2 stops19h 57m

£547

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Mon 9/11

06:00-09:40

2 stops43h 40m

London Heathrow

Thu 12/11

06:50-18:47

2 stops19h 57m

£554

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Sun 1/11

13:29-07:40

2 stops34h 11m

London Heathrow

Wed 4/11

06:50-18:47

2 stops19h 57m

£558

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Sun 10/1

05:00-11:50

2 stops22h 50m

London Heathrow

Sun 24/1

14:45-22:39

1 stop15h 54m

£593

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Sun 17/1

06:00-12:20

1 stop22h 20m

London Heathrow

Mon 25/1

14:45-22:39

1 stop15h 54m

£596

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Tue 8/12

12:00-12:20

1 stop16h 20m

London Heathrow

Tue 15/12

14:45-22:39

1 stop15h 54m

£596

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Wed 2/12

06:00-12:20

1 stop22h 20m

London Heathrow

Wed 9/12

14:45-22:39

1 stop15h 54m

£596
Fastest return journey

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Tue 26/1

15:09-12:00

1 stop12h 51m

London Heathrow

Sun 31/1

14:45-22:39

1 stop15h 54m

£596

OntarioLondon

ONT Ontario - LHR London Heathrow

ONTLHR

Ontario

Wed 9/12

12:46-10:00

1 stop13h 14m

London Heathrow

Wed 16/12

14:45-22:39

1 stop15h 54m

£596

Flights are sorted by cheapest return flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to London from

How to get the cheapest flight ticket from Ontario to London Heathrow Airport

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the typical price of a round-trip flight between Ontario and London Heathrow Airport?

Prices are currently low for flights on this route.

Typical prices usually range from £657 to £781.
The lowest price recently found on this route was £547.

What is the cheapest month to fly to London Heathrow Airport?

In general, November is the cheapest month to fly from Ontario to London Heathrow Airport. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around £463. The month of December is another great option to travel to London Heathrow Airport, with average flight prices from Ontario averaging around £499.

What is the cheapest day to depart on your flight to London Heathrow Airport?

On average, the least expensive day to fly to London Heathrow Airport from Ontario is on a Wednesday. momondo users have found tickets for Wednesday departures for as low as £656. However, this price may fluctuate depending on the airline, the season, and holidays. Be sure to avoid booking your departure on a Thursday as prices are generally higher than usual. According to our data, the average ticket price to London Heathrow Airport on Thursday is £781.

What is the cheapest time of day to depart on your flight to London Heathrow Airport?

According to our data, the cheapest time of day to fly to London Heathrow Airport is at midday. momondo users have found flights departing from Ontario to London Heathrow Airport at midday for as low as £454. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. If you have a flexible travel schedule, then try to avoid flying in the afternoon when prices are £747 on average. Flights to London Heathrow Airport from Ontario in the afternoon are generally more expensive because this time of day is more convenient for travellers’ schedules.

When to book flights from Ontario to London Heathrow Airport

Are you open to changing your travel dates? Check out the ideal times to fly from Ontario to London Heathrow Airport according to our flight data. Find out which month and days have the cheapest flights.
Estimated return price

Cheap Ontario to London Heathrow Airport (ONT to LHR) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Ontario to London Heathrow Airport

Fastest flight time

12h 35m

Direct flights

None
The fastest flight from Ontario to London Heathrow Airport takes 12h 35m
There are no direct flights from Ontario to London Heathrow Airport. There are no popular flight routes from Ontario to London Heathrow Airport.
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Frequently asked questions about flying from Ontario to London Heathrow Airport

  • How far is Ontario to London Heathrow by plane?

    London Heathrow is 5408.1 mi away from Ontario. In terms of flight time, this usually takes a little over 12h 35m.

  • When did momondo last update prices for flights from Ontario Airport to London Heathrow Airport?

    Prices for flights from Ontario Airport to London Heathrow Airport refresh daily.

  • How old do you have to be to fly from Ontario Airport to London Heathrow Airport?

    The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Ontario Airport to London Heathrow Airport.

  • What documentation or ID do you need to fly to London Heathrow Airport?

    The travel and health documents you'll need for your trip to London Heathrow Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at London Heathrow Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

Travelling to a place near London?

Book flights to London if you plan to visit one of these locations
Eastbourne
Wembley
Gatwick
Milton Keynes
Stratford-upon-Avon
Luton
Southend-on-Sea
Slough
Northampton
Ipswich
Maidstone
Swindon
Folkestone
Ilford
Hastings
Poole
Canterbury
Guildford
Chichester
Hayes

Why use momondo?

Why should I use momondo to find a flight deal from Ontario to London?

momondo compares prices from hundreds of airlines and agents so you can find and book the best deal on flights from Ontario to London . Millions of users trust and use momondo every year so you are in good hands.

Can I find flights from Ontario to London with flexible booking policies on momondo?

Flights from Ontario to London with flexible booking policies can be found by using the search form above and then selecting our dedicated flexible booking filter, which will highlight only the flights where this policy is applied.

How can momondo help me find flights from Ontario to London?

Once you have performed a search in the form on the page, momondo provides useful filters and insights. We can show you the cheapest days and times to fly as well as help filter your options to help you make an informed choice when booking flights to London from Ontario.

I’m not ready to book a flight from Ontario to London right now. Can momondo alert me if prices change?

Price alerts on flights to London from Ontario are quick and easy to set up on momondo. Simply perform a search and select the price alert feature. It is as simple as that.

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