£354 Cheap Flights from Ontario Intl. Airport (ONT) to London (LHR)

View £354 flight on Sun, 20 Sept 2026Opens in a new window

Popular airlines from Los Angeles - Ontario Intl. Airport (ONT) to Heathrow Airport (LHR)

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Cheap Flights from Ontario Intl. Airport (ONT) to London (LHR)

Prices were available within the past 7 days and start at £354 for one-way flights and £652 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Iberia
Mon, 17 Aug - Tue, 25 Aug
ONT
Ontario
LHR
London
£652 Return, found 3 days ago
£652
Return
found 3 days ago
Select Iberia flight, departing Mon, 17 Aug from Ontario to London, returning Tue, 25 Aug, priced at £652 found 3 days ago
British Airways
Tue, 12 Jan - Wed, 20 Jan
ONT
Ontario
LHR
London
£677 Return, found 3 days ago
£677
Return
found 3 days ago
Select British Airways flight, departing Tue, 12 Jan from Ontario to London, returning Wed, 20 Jan, priced at £677 found 3 days ago
Virgin Atlantic
Mon, 17 Aug - Tue, 25 Aug
ONT
Ontario
LHR
London
£677 Return, found 3 days ago
£677
Return
found 3 days ago
Select Virgin Atlantic flight, departing Mon, 17 Aug from Ontario to London, returning Tue, 25 Aug, priced at £677 found 3 days ago
British Airways
Mon, 17 Aug - Tue, 25 Aug
ONT
Ontario
LHR
London
£677 Return, found 3 days ago
£677
Return
found 3 days ago
Select British Airways flight, departing Mon, 17 Aug from Ontario to London, returning Tue, 25 Aug, priced at £677 found 3 days ago
United
Wed, 30 Sept - Fri, 27 Nov
ONT
Ontario
LHR
London
£679 Return, found 5 days ago
£679
Return
found 5 days ago
Select United flight, departing Wed, 30 Sept from Ontario to London, returning Fri, 27 Nov, priced at £679 found 5 days ago
KLM
Mon, 17 Aug - Tue, 25 Aug
ONT
Ontario
LHR
London
£684 Return, found 3 days ago
£684
Return
found 3 days ago
Select KLM flight, departing Mon, 17 Aug from Ontario to London, returning Tue, 25 Aug, priced at £684 found 3 days ago
Air Canada
Mon, 17 Aug - Tue, 25 Aug
ONT
Ontario
LHR
London
£685 Return, found 3 days ago
£685
Return
found 3 days ago
Select Air Canada flight, departing Mon, 17 Aug from Ontario to London, returning Tue, 25 Aug, priced at £685 found 3 days ago
Air Canada
Mon, 17 Aug - Tue, 25 Aug
ONT
Ontario
LHR
London
£689 Return, found 3 days ago
£689
Return
found 3 days ago
Select Air Canada flight, departing Mon, 17 Aug from Ontario to London, returning Tue, 25 Aug, priced at £689 found 3 days ago
KLM
Mon, 17 Aug - Tue, 25 Aug
ONT
Ontario
LHR
London
£693 Return, found 3 days ago
£693
Return
found 3 days ago
Select KLM flight, departing Mon, 17 Aug from Ontario to London, returning Tue, 25 Aug, priced at £693 found 3 days ago
Virgin Atlantic
Mon, 17 Aug - Tue, 25 Aug
ONT
Ontario
LHR
London
£698 Return, found 3 days ago
£698
Return
found 3 days ago
Select Virgin Atlantic flight, departing Mon, 17 Aug from Ontario to London, returning Tue, 25 Aug, priced at £698 found 3 days ago

Frequently asked questions

How much does a flight from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow) cost?
One-way flights typically cost between £483 and £2,654 and return flights often range between £483 and £2,654. Flight prices vary based on the month and day of the week you want to travel, as well as the airline and how far in advance you book your ticket. Filter your search on Expedia by "Price (lowest to highest)" to see the cheapest fares first, and use the Price Tracking tool to receive alerts when Anaa (AAA) to Toronto, ON (YYZ-Pearson Intl.) ticket fares go up or down.
How do I find cheap flights from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow)?
To find a cheap flight from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow), be flexible with your dates. Traveling outside of peak vacation months and booking a mid-week flight can help you save. Early morning and late night flights are often more affordable, too. Expedia allows you to compare flight times, airlines and routes all in one place to find low fares. You can also set up Price Tracking and receive alerts when fares go up or down.
What is the best time to fly from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow)?
The best time to fly is usually mid-week (Tuesday or Wednesday) and during early morning hours as flights tend to be cheaper, less crowded, and generally more on-time. Avoid major holidays and peak vacation seasons for smoother travel. Combining off-peak days and hours often gives the best combination of cost, comfort, and convenience.
How many flights per day from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow)?
There are approximately 34 connecting flights per day from Ontario International Airport (ONT) to London Heathrow (LHR). Some common connection points include Seattle - Tacoma Intl. (SEA), Dallas-Fort Worth Intl. (DFW), and Sky Harbor Intl. (PHX).
What is the earliest flight from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow)?
The earliest flight from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow) typically departs at approximately 12:55 AM local time. This service is operated by American Airlines and is a seasonal service active in March. An early departure like this can help maximise your time at your destination. To compare early flights on Expedia, select the "Early Morning" and "Morning" filters in your search.
What day of the week has the most flights from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow)?
You'll typically find the most flights from Los Angeles - Ontario Intl. (ONT) to London Heathrow (LHR) on a Saturday, with around 40 flights available. This gives you plenty of options for your travel plans. Major airlines on this route include American Airlines, Delta Air Lines, and United Airlines. Flight options are fairly consistent throughout the week, with Saturdays offering only slightly more flights than other days.
What are the most popular departure times for flights from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow)?
The most popular departure times for flights from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow) are between 12pm and 3pm. Approximately 34% of passengers prefer this time window. Many major carriers, including American Airlines, Delta Air Lines and United Airlines, offer flights during this window. This timing works well because it allows for a morning in Ontario before your flight, and you'll arrive in London in the morning, ready to start your day.
How long does it take to fly from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow)?
A flight from ONT to LHR with a layover takes around 16 hours 20 minutes, with the route covering approximately 5,411 miles. Keep in mind that actual flight times can vary due to wind patterns, weather, and air traffic.
Can you fly business or first class from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow)?
Select the "Business class" and "First class" filters when looking for ONT to LHR flights on Expedia. This is the easiest way to compare prices, routes and flight times for your trip.
How do I earn miles on a Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow) flight with Expedia?
It's easy to earn miles on a Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow) flight when you book with Expedia. Before you confirm your booking, simply select your frequent flyer program and enter your program number. As a member of One Key™, you can also earn OneKeyCash™* on top of your airline miles when you book with Expedia. *Excludes taxes and fees. OneKeyCash is not redeemable for cash and can only be used on Expedia and other participating brands.
What airports do you fly into for London from Los Angeles - Ontario Intl. (ONT)?
From Los Angeles - Ontario Intl. (ONT), you can fly into Heathrow (LHR), Gatwick (LGW), London Intl. (YXU) and London City (LCY) in London. Some flights may connect through major hubs like Sky Harbor Intl. (PHX), Dallas-Fort Worth Intl. (DFW), San Francisco Intl. (SFO) before reaching London. Compare routes and airports on Expedia to find the best flight options for your travel plans.
Is it cheaper to buy a plane ticket from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow) at the last minute?
Typically, booking a last minute flight from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow) will be more expensive than booking in advance. As the departure date approaches, there are usually fewer seats available which can drive up the cost. However, if there's some wiggle room with your travel dates and times, you could bag a cheap last-minute fare.
Is it cheaper to book a Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow) flight and hotel package?
Securing a Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow) flight and hotel package is usually cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels all in one place. Select from our extensive range of stays and then add flights, activities and car rentals to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow)?
If you booked your Ontario, CA (ONT-Los Angeles - Ontario Intl.) to London (LHR-Heathrow) flight within the last 24 hours, you may be able to modify or cancel it without any fees. Depending on the airline and the type of ticket you have, additional charges may apply for changes beyond this timeframe. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal if you'd like more information.

Travel information

Origin airport
Ontario Intl. Airport
Destination airport
Heathrow
Airlines serving
Alaska Airlines, British Airways, Delta, United
Return price
£652
Distance
8655 km

Book with confidence

Compare flights from Ontario Intl. Airport to London easily and book with confidence

For travelling on business or for pleasure, Expedia makes it easy to book your flights from Ontario Intl. Airport to London. Operating between them flights per day, 20 airlines cover the route. And fly direct, getting you to Heathrow in just hours. If you have a preferred carrier, use our advanced search tool to find the right flight from Ontario Intl. Airport to Heathrow.  

To make things even better, in the advanced search, you can also choose to fly economy, premium economy, business or first class, select your maximum number of stops, and pick your preferred departure and arrival time. You can also opt for refundable and direct flights. 

Grab a great deal on your flight from Ontario Intl. Airport (ONT) to Heathrow (LHR)

The easiest way to view the best deals on flights from Ontario Intl. Airport to London today is to enter your travel dates and hit search. From here, you can sort your results by price to see the cheapest flights first. Right now, return flights from Ontario Intl. Airport to Heathrow start at just £652 and range up to £698.  

To find an even better deal, try  

  • being flexible on your dates – midweek flights can be cheaper
  • looking for other airports near Ontario Intl. Airport and London
  • booking your flight during August, the cheapest month on this route
  • varying your flight times – early morning and late at night are sometimes cheaper 

Why you should book your Ontario Intl. Airport to London flight with Expedia!

We cater for all flight types, cabin classes and airlines. So whether you’re booking flights from Ontario Intl. Airport to Heathrow for a budget break or a business trip with a bit of pleasure thrown in, we make it easy to secure the seat that’s right for you.  

Thanks to our supersized inventory that offers great choice all in one place, you know you’ll get a great deal with Expedia. Especially if you bundle your flight together with your hotel, you will unlock amazing savings. For added peace of mind, you can choose flexible bookings or filter to find refundable options, so you won’t pay a fee to change your flight.  

Compare flights from Ontario Intl. Airport to London easily and book with confidence

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