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Cheap flights from London to Ontario from £315

LON — ONT
4 Dec — 11 Dec1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from London to Ontario

Enter your travel dates to find the best prices.

Cheapest flights from London to Ontario

Wed 11/1114:45 -
1 stop35h 32m
Tue 17/1112:02 -
1 stop16h 18m
Deal found 30/10£412
Tue 10/1114:45 -
1 stop28h 33m
Wed 25/1111:55 -
1 stop16h 25m
Deal found 30/10£417
Sun 8/1114:45 -
1 stop16h 21m
Sun 15/1106:00 -
1 stop22h 20m
Deal found 30/10£420
Fri 6/1114:45 -
1 stop32h 28m
Sat 5/1206:00 -
1 stop22h 20m
Deal found 30/10£421
Fri 13/1114:45 -
1 stop16h 21m
Fri 27/1106:00 -
1 stop22h 20m
Deal found 2/11£423
Sat 21/1114:45 -
1 stop16h 46m
Mon 7/1206:00 -
1 stop22h 20m
Deal found 3/11£423
Mon 7/1214:45 -
1 stop16h 14m
Wed 23/1220:59 -
1 stop31h 21m
Deal found 3/11£424
Sun 8/1114:45 -
1 stop16h 21m
Sun 22/1106:00 -
1 stop22h 20m
Deal found 31/10£426
Mon 7/1214:45 -
1 stop33h 20m
Tue 12/111:34 -
1 stop16h 46m
Deal found 3/11£426
Wed 18/1114:45 -
1 stop28h 28m
Sun 22/1106:00 -
1 stop22h 20m
Deal found 30/10£427
Tue 1/1210:00 -
2 stops18h 58m
Tue 8/1212:20 -
2 stops19h 25m
Deal found 2/11£626
Thu 26/1111:00 -
2 stops31h 45m
Thu 3/1206:00 -
3 stops22h 55m
Deal found 3/11£644

Find flight deals from London to Ontario

Round-trip from

£415

One-way from

£315

Popular in

June

Cheapest in

February

Average price

£572
Alaska Airlines
  • Alaska Airlines
  • 13/1-19/1
  • 2 total stops
  • 37h 16m total
  • London to Ontario
Search Deals
8/1-31/12
  • 8/1-31/12
  • 3 total stops
  • 51h 30m total
  • London to Ontario
Search Deals
Highest demand for flights based on searches. 14% potential increase in price (£67 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease (£12 potential savings vs. average return price).
Search Deals
Average for round-trip flights in November 2026
Search Deals

Cheapflights Fare Finder

 
Use the filters below to find and compare flights from London to Ontario that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest return flight

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Mon 16/11

14:45-23:06

1 stop16h 21m

Ontario

Mon 1/3

12:00-12:20

1 stop16h 20m

£432

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Sun 15/11

14:45-23:06

1 stop16h 21m

Ontario

Tue 2/3

12:00-12:20

1 stop16h 20m

£432

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Mon 9/11

14:45-23:06

1 stop16h 21m

Ontario

Mon 16/11

06:00-12:20

1 stop22h 20m

£433

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Fri 13/11

14:45-23:06

1 stop16h 21m

Ontario

Sun 22/11

06:00-12:20

1 stop22h 20m

£433

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Thu 12/11

14:45-23:06

1 stop16h 21m

Ontario

Sun 15/11

06:00-12:20

1 stop22h 20m

£433

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Mon 7/12

14:45-22:59

1 stop16h 14m

Ontario

Sun 10/1

06:00-12:20

1 stop22h 20m

£435

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Wed 6/1

10:25-18:50

1 stop16h 25m

Ontario

Wed 31/12

00:00-09:00

Nonstop0h 00m

£449

LondonOntario

LGW London Gatwick - ONT Ontario

LGWONT

London Gatwick

Thu 19/11

11:00-23:51

2 stops20h 51m

Ontario

Wed 31/12

00:00-09:00

Nonstop0h 00m

£502

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Wed 16/12

07:40-18:44

1 stop19h 04m

Ontario

Wed 31/12

00:00-09:00

Nonstop0h 00m

£505

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Sat 5/12

14:45-11:13

1 stop28h 28m

Ontario

Sat 12/12

06:00-12:20

1 stop22h 20m

£552

Flights are sorted by cheapest return flights first.

Deals found on 31/10

Showing 1-10 of 43 resultsSorted by cheapest first
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Best time to book a flight from London to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from London with our price prediction graph.
Estimated return price

Cheapflights Insights

Everything you need to know about your flight from London to Ontario

What is the cheapest month to book a flight from London to Ontario?

Currently, January is the cheapest month in which you can book a flight from London to Ontario (average of £412). Flying from London to Ontario in June is currently the most expensive (average of £657). 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 for a return flight from London to Ontario?

Airfare is below average for this route at the moment.
London to Ontario flights typically cost between £485 and £612 in November.
The cheapest return price found within the last 5 days was £421 on Alaska Airlines (15 Nov–6 Dec).

What’s the top stopover airport for flights from London to Ontario?

Dallas (DFW) – chosen by Cheapflights users on 29% of one-stop itineraries from London to Ontario on Cheapflights.

What’s the cheapest stopover airport for flights from London to Ontario?

Denver (DEN) is the most affordable one-stop option, with an average return flight price of £411.

What’s the fastest stopover option from London to Ontario?

Flights via Denver (DEN) have the shortest average one-way travel time for one-stop routes: 13h 54m.

Which airport typically offers the quickest stopover for flights from London to Ontario?

Flights via Denver (DEN) offer the fastest connection on this route, with an average stopover time of 1h 42m.

Reviews of airlines servicing Ontario

Read through reviews of airlines operating flights from London to Ontario, such as Alaska Airlines,Delta, andVirgin Atlantic. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
7.9
Good
13,142 reviews
Check prices

Overall

7.9

Entertainment

7.0

Food

7.0

Comfort

7.8

Crew

8.5

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Chris,Aug 2026

GEG - SFO

Our flight was delayed multiple times over the course of the day for a total of almost ten hours. It was supposed to be a two-hour flight from San Francisco to Spokane. It turned into a nightmare of waiting all day in the airport, not knowing whether we would fly or not, whether we would miss my son's wedding and lose the expenses already incurred for car rental and accommodations. The Alaska staff seemed clueless and never gave us any convincing or definitive information. The airline offered food vouchers and discounts on future flights to make up for the trouble. However, the information about these concessions was not timely, nor were the vouchers themselves very useful. We were a family group of four people. The airline decided to give us one food voucher for $96, which is barely enough for four to get a sandwich and a drink each. Only by persistently addressing the airport food retailers were we able to get anything at all. Then, taking the exact opposite approach, the airline sent me, the original purchaser of all four tickets and the only email account they had, four vouchers for $150 each in the names of each of the four passengers. So, any one of us could get a discount on a future flight with Alaska in that amount. But I originally paid for all the tickets. It makes no sense, except to suggest that Alaska chooses the way to distribute vouchers that seems most likely to minimize the probability that they will be utilized. In my opinion, I should be offered a total refund for the ordeal we were forced to endure or at least a discount voucher for the entire $600.
Alaska Airlines
7.9
Good
13,142 reviews
Alaska Airlines
7.9
Good
13,142 reviews
Check prices

Overall

7.9

Entertainment

7.0

Food

7.0

Comfort

7.8

Crew

8.5

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Chris,Aug 2026

GEG - SFO

Our flight was delayed multiple times over the course of the day for a total of almost ten hours. It was supposed to be a two-hour flight from San Francisco to Spokane. It turned into a nightmare of waiting all day in the airport, not knowing whether we would fly or not, whether we would miss my son's wedding and lose the expenses already incurred for car rental and accommodations. The Alaska staff seemed clueless and never gave us any convincing or definitive information. The airline offered food vouchers and discounts on future flights to make up for the trouble. However, the information about these concessions was not timely, nor were the vouchers themselves very useful. We were a family group of four people. The airline decided to give us one food voucher for $96, which is barely enough for four to get a sandwich and a drink each. Only by persistently addressing the airport food retailers were we able to get anything at all. Then, taking the exact opposite approach, the airline sent me, the original purchaser of all four tickets and the only email account they had, four vouchers for $150 each in the names of each of the four passengers. So, any one of us could get a discount on a future flight with Alaska in that amount. But I originally paid for all the tickets. It makes no sense, except to suggest that Alaska chooses the way to distribute vouchers that seems most likely to minimize the probability that they will be utilized. In my opinion, I should be offered a total refund for the ordeal we were forced to endure or at least a discount voucher for the entire $600.
Delta
7.8
Good
8,697 reviews
Alaska Airlines
7.9
Good
13,142 reviews
Check prices

Overall

7.9

Entertainment

7.0

Food

7.0

Comfort

7.8

Crew

8.5

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Chris,Aug 2026

GEG - SFO

Our flight was delayed multiple times over the course of the day for a total of almost ten hours. It was supposed to be a two-hour flight from San Francisco to Spokane. It turned into a nightmare of waiting all day in the airport, not knowing whether we would fly or not, whether we would miss my son's wedding and lose the expenses already incurred for car rental and accommodations. The Alaska staff seemed clueless and never gave us any convincing or definitive information. The airline offered food vouchers and discounts on future flights to make up for the trouble. However, the information about these concessions was not timely, nor were the vouchers themselves very useful. We were a family group of four people. The airline decided to give us one food voucher for $96, which is barely enough for four to get a sandwich and a drink each. Only by persistently addressing the airport food retailers were we able to get anything at all. Then, taking the exact opposite approach, the airline sent me, the original purchaser of all four tickets and the only email account they had, four vouchers for $150 each in the names of each of the four passengers. So, any one of us could get a discount on a future flight with Alaska in that amount. But I originally paid for all the tickets. It makes no sense, except to suggest that Alaska chooses the way to distribute vouchers that seems most likely to minimize the probability that they will be utilized. In my opinion, I should be offered a total refund for the ordeal we were forced to endure or at least a discount voucher for the entire $600.
Virgin Atlantic
7.5
Good
697 reviews
Alaska Airlines
7.9
Good
13,142 reviews
Check prices

Overall

7.9

Entertainment

7.0

Food

7.0

Comfort

7.8

Crew

8.5

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Chris,Aug 2026

GEG - SFO

Our flight was delayed multiple times over the course of the day for a total of almost ten hours. It was supposed to be a two-hour flight from San Francisco to Spokane. It turned into a nightmare of waiting all day in the airport, not knowing whether we would fly or not, whether we would miss my son's wedding and lose the expenses already incurred for car rental and accommodations. The Alaska staff seemed clueless and never gave us any convincing or definitive information. The airline offered food vouchers and discounts on future flights to make up for the trouble. However, the information about these concessions was not timely, nor were the vouchers themselves very useful. We were a family group of four people. The airline decided to give us one food voucher for $96, which is barely enough for four to get a sandwich and a drink each. Only by persistently addressing the airport food retailers were we able to get anything at all. Then, taking the exact opposite approach, the airline sent me, the original purchaser of all four tickets and the only email account they had, four vouchers for $150 each in the names of each of the four passengers. So, any one of us could get a discount on a future flight with Alaska in that amount. But I originally paid for all the tickets. It makes no sense, except to suggest that Alaska chooses the way to distribute vouchers that seems most likely to minimize the probability that they will be utilized. In my opinion, I should be offered a total refund for the ordeal we were forced to endure or at least a discount voucher for the entire $600.
United Airlines
7.3
Good
10,460 reviews
Alaska Airlines
7.9
Good
13,142 reviews
Check prices

Overall

7.9

Entertainment

7.0

Food

7.0

Comfort

7.8

Crew

8.5

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Chris,Aug 2026

GEG - SFO

Our flight was delayed multiple times over the course of the day for a total of almost ten hours. It was supposed to be a two-hour flight from San Francisco to Spokane. It turned into a nightmare of waiting all day in the airport, not knowing whether we would fly or not, whether we would miss my son's wedding and lose the expenses already incurred for car rental and accommodations. The Alaska staff seemed clueless and never gave us any convincing or definitive information. The airline offered food vouchers and discounts on future flights to make up for the trouble. However, the information about these concessions was not timely, nor were the vouchers themselves very useful. We were a family group of four people. The airline decided to give us one food voucher for $96, which is barely enough for four to get a sandwich and a drink each. Only by persistently addressing the airport food retailers were we able to get anything at all. Then, taking the exact opposite approach, the airline sent me, the original purchaser of all four tickets and the only email account they had, four vouchers for $150 each in the names of each of the four passengers. So, any one of us could get a discount on a future flight with Alaska in that amount. But I originally paid for all the tickets. It makes no sense, except to suggest that Alaska chooses the way to distribute vouchers that seems most likely to minimize the probability that they will be utilized. In my opinion, I should be offered a total refund for the ordeal we were forced to endure or at least a discount voucher for the entire $600.
British Airways
6.7
Okay
8,282 reviews
Alaska Airlines
7.9
Good
13,142 reviews
Check prices

Overall

7.9

Entertainment

7.0

Food

7.0

Comfort

7.8

Crew

8.5

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Chris,Aug 2026

GEG - SFO

Our flight was delayed multiple times over the course of the day for a total of almost ten hours. It was supposed to be a two-hour flight from San Francisco to Spokane. It turned into a nightmare of waiting all day in the airport, not knowing whether we would fly or not, whether we would miss my son's wedding and lose the expenses already incurred for car rental and accommodations. The Alaska staff seemed clueless and never gave us any convincing or definitive information. The airline offered food vouchers and discounts on future flights to make up for the trouble. However, the information about these concessions was not timely, nor were the vouchers themselves very useful. We were a family group of four people. The airline decided to give us one food voucher for $96, which is barely enough for four to get a sandwich and a drink each. Only by persistently addressing the airport food retailers were we able to get anything at all. Then, taking the exact opposite approach, the airline sent me, the original purchaser of all four tickets and the only email account they had, four vouchers for $150 each in the names of each of the four passengers. So, any one of us could get a discount on a future flight with Alaska in that amount. But I originally paid for all the tickets. It makes no sense, except to suggest that Alaska chooses the way to distribute vouchers that seems most likely to minimize the probability that they will be utilized. In my opinion, I should be offered a total refund for the ordeal we were forced to endure or at least a discount voucher for the entire $600.

Related info for your journey

  • What airport do you fly into for flights to Ontario from London?

    Most people fly into Ontario (ONT) if they book a flight to Ontario from London. On average, Ontario has 0 inbound flights from London per day from 4 airlines. Ontario is conveniently located just 3.1 mi from Ontario’s city center.

  • How long is the flight from London to Ontario?

    Airlines like Alaska Airlines and British Airways fly from London to Ontario in about 16h 21m. The time it takes to get you to your destination can typically vary by up to 26h 51m. The distance from London to Ontario is about 5407 mi. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.

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

    According to our current data, United Airlines (£373), Virgin Atlantic (£375), and British Airways (£406) offers the cheapest pricing from London to Ontario. You may be able to fly from London to Ontario for 28% less than the average price by searching for these airlines.

  • What are the most popular routes from London to Ontario?

    The most popular route from London to Ontario is London Heathrow - Ontario. You may also consider London Gatwick - Ontario or London City - Ontario.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from London to Ontario 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 London to Ontario?

    Currently, January is the cheapest month in which you can book a flight from London to Ontario (average of £412). Flying from London to Ontario in June is currently the most expensive (average of £657). 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

Browse thousands of different options on Cheapflights for your next trip

Alternative routes for London to Ontario

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Top 4 airlines flying from London to Ontario

AirlineCheapestAverageFlexibilityOn-time
United AirlinesCheapest£373Average£516FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
Virgin AtlanticCheapest£375Average£511FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
British AirwaysCheapest£406Average£516FlexibilityNo cancel feeOn-time70%
Search British Airways flights
Alaska AirlinesCheapest£426Average£443FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights

Fly with Cheapflights

How does Cheapflights help users find flights from London to Ontario?

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

Cheapflights helps you find that perfect flight to Ontario from London by searching from hundreds of airlines and agencies you know and love. We are also free to use, in case you were wondering!

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

Cheapflights does show flights with no change fees to all users. To see these options for flights from London to Ontario, users can toggle the no change fees filter when performing a flight search.

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

Yes, Cheapflights offers price alerts on London to Ontario flights so you can book your travel at the perfect time. Price Alerts can be enabled by clicking the bell icon next to the flight deals above and providing your email address where you want to receive the alerts.

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