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Cheap flights from London to Ontario from £349

LON — ONT
4 Nov — 11 Nov1
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

Fri 9/1017:00 -
1 stop14h 42m
Thu 22/1006:02 -
1 stop25h 03m
Deal found 1/10£402
Wed 21/1011:45 -
2 stops18h 58m
Wed 10/212:00 -
1 stop13h 00m
Deal found 30/9£408
Wed 21/1011:45 -
2 stops18h 58m
Tue 9/207:00 -
1 stop16h 50m
Deal found 30/9£409
Mon 12/1017:00 -
1 stop33h 00m
Tue 27/1011:13 -
1 stop18h 07m
Deal found 4/10£413
Thu 22/1010:55 -
1 stop21h 00m
Tue 9/207:00 -
1 stop19h 40m
Deal found 30/9£414
Wed 21/1009:55 -
2 stops20h 48m
Mon 8/217:05 -
2 stops19h 05m
Deal found 30/9£421
Thu 29/1014:45 -
1 stop26h 32m
Wed 4/1112:02 -
1 stop16h 18m
Deal found 30/9£422
Mon 12/1017:00 -
1 stop28h 16m
Sun 18/1006:02 -
1 stop25h 03m
Deal found 3/10£423
Tue 13/1017:00 -
1 stop25h 17m
Tue 20/1014:13 -
1 stop16h 52m
Deal found 5/10£424
Thu 22/1017:00 -
1 stop14h 42m
Wed 10/211:36 -
1 stop16h 44m
Deal found 30/9£424
Fri 30/1014:45 -
1 stop15h 57m
Fri 13/1106:00 -
1 stop22h 20m
Deal found 1/10£425
Mon 12/1017:00 -
2 stops37h 43m
Fri 6/1112:16 -
2 stops19h 29m
Deal found 5/10£516

Find flight deals from London to Ontario

Round-trip from

£408

One-way from

£349

Popular in

June

Cheapest in

March

Average price

£466
Virgin Atlantic
  • Virgin Atlantic
  • 21/10-10/2
  • 3 total stops
  • 31h 58m total
  • London to Ontario
Search Deals
Alaska Airlines
  • Alaska Airlines
  • 19/11-31/12
  • 1 total stop
  • 16h 21m total
  • London to Ontario
Search Deals
Highest demand for flights based on searches. 12% potential increase in price (£58 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease (£11 potential savings vs. average return price).
Search Deals
Average for round-trip flights in October 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 23/11

14:45-23:31

1 stop16h 46m

Ontario

Wed 9/12

11:57-12:20

1 stop16h 23m

£428

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Sun 1/11

14:45-23:06

1 stop16h 21m

Ontario

Sat 14/11

12:02-12:20

1 stop16h 18m

£428
Fastest return journey

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Thu 7/1

14:45-22:41

1 stop15h 56m

Ontario

Wed 31/12

00:00-09:00

Nonstop0h 00m

£431

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Mon 19/10

11:40-22:43

1 stop19h 03m

Ontario

Mon 8/2

07:00-10:40

1 stop19h 40m

£435

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Wed 21/10

10:55-23:55

1 stop21h 00m

Ontario

Mon 8/2

07:00-07:50

1 stop16h 50m

£435

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Tue 20/10

18:35-16:23

2 stops29h 48m

Ontario

Tue 9/2

17:05-20:10

2 stops19h 05m

£435

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Mon 19/10

20:05-17:12

2 stops29h 07m

Ontario

Tue 9/2

15:30-20:10

2 stops20h 40m

£435

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Fri 27/11

14:45-23:31

1 stop16h 46m

Ontario

Sun 6/12

06:00-12:20

1 stop22h 20m

£436

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Mon 23/11

14:45-23:31

1 stop16h 46m

Ontario

Thu 10/12

06:00-12:20

1 stop22h 20m

£436

LondonOntario

LHR London Heathrow - ONT Ontario

LHRONT

London Heathrow

Fri 27/11

14:45-23:31

1 stop16h 46m

Ontario

Wed 9/12

11:57-12:20

1 stop16h 23m

£436

Flights are sorted by cheapest return flights first.

Deals found on 2/10

Showing 1-10 of 37 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 £418). Flying from London to Ontario in June is currently the most expensive (average of £666). 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 £410 and £518 in October.
The cheapest return price found within the last 5 days was £408 on Virgin Atlantic (21 Oct–10 Feb).

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

Dallas (DFW) – chosen by Cheapflights users on 32% 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 £417.

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, andUnited Airlines. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
7.9
Good
13,016 reviews
Check prices

Crew

8.5

Overall

7.9

Food

7.0

Boarding

8.1

Entertainment

7.0

Comfort

7.8

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
13,016 reviews
Alaska Airlines
7.9
Good
13,016 reviews
Check prices

Crew

8.5

Overall

7.9

Food

7.0

Boarding

8.1

Entertainment

7.0

Comfort

7.8

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
8,629 reviews
Alaska Airlines
7.9
Good
13,016 reviews
Check prices

Crew

8.5

Overall

7.9

Food

7.0

Boarding

8.1

Entertainment

7.0

Comfort

7.8

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
7.4
Good
10,286 reviews
Alaska Airlines
7.9
Good
13,016 reviews
Check prices

Crew

8.5

Overall

7.9

Food

7.0

Boarding

8.1

Entertainment

7.0

Comfort

7.8

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
7.4
Good
693 reviews
Alaska Airlines
7.9
Good
13,016 reviews
Check prices

Crew

8.5

Overall

7.9

Food

7.0

Boarding

8.1

Entertainment

7.0

Comfort

7.8

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
8,244 reviews
Alaska Airlines
7.9
Good
13,016 reviews
Check prices

Crew

8.5

Overall

7.9

Food

7.0

Boarding

8.1

Entertainment

7.0

Comfort

7.8

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, Delta, and KLM fly from London to Ontario in about 16h 46m. The time it takes to get you to your destination can typically vary by up to 4h 14m. 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 (£377), Virgin Atlantic (£379), and British Airways (£411) offers the cheapest pricing from London to Ontario. You may be able to fly from London to Ontario for 30% 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 £418). Flying from London to Ontario in June is currently the most expensive (average of £666). 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

Heathrow to Los Angeles flights
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Top 4 airlines flying from London to Ontario

AirlineCheapestAverageFlexibilityOn-time
United AirlinesCheapest£377Average£522FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
Virgin AtlanticCheapest£379Average£517FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
British AirwaysCheapest£411Average£523FlexibilityNo cancel feeOn-time70%
Search British Airways flights
Alaska AirlinesCheapest£432Average£448FlexibilityNo cancel feeOn-time75%
Search Alaska Airlines flights

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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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