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448 € Cheap Flights from Ontario International to London Heathrow

Compare Ontario International to London Heathrow flight deals

Find the cheapest month or even day of the year to fly to London Heathrow

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Flight deals from Ontario International to London Heathrow

Looking for a cheap last-minute deal or the best return flight from Ontario International to London Heathrow? Find the lowest prices on one-way and return tickets right here.
London.448 € per passenger.Departing Sun, 5 Oct, returning Tue, 21 Oct.Return flight with KLM.Outbound indirect flight with KLM, departs from Ontario International on Sun, 5 Oct, arriving in London Heathrow.Inbound indirect flight with KLM, departs from London Heathrow on Tue, 21 Oct, arriving in Ontario International.Price includes taxes and charges.From 448 €, select.
London.449 € per passenger.Departing Sun, 7 Sep, returning Tue, 23 Sep.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Sun, 7 Sep, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Tue, 23 Sep, arriving in Ontario International.Price includes taxes and charges.From 449 €, select.
London.497 € per passenger.Departing Sun, 15 Feb, returning Sun, 22 Feb.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Sun, 15 Feb, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Sun, 22 Feb, arriving in Ontario International.Price includes taxes and charges.From 497 €, select.
London.533 € per passenger.Departing Mon, 8 Dec, returning Sat, 27 Dec.Return flight with Air France and KLM.Outbound indirect flight with Air France, departs from Ontario International on Mon, 8 Dec, arriving in London Heathrow.Inbound indirect flight with KLM, departs from London Heathrow on Sat, 27 Dec, arriving in Ontario International.Price includes taxes and charges.From 533 €, select.
London.535 € per passenger.Departing Sat, 8 Nov, returning Sun, 16 Nov.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Sat, 8 Nov, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Sun, 16 Nov, arriving in Ontario International.Price includes taxes and charges.From 535 €, select.
London.543 € per passenger.Departing Wed, 14 Jan, returning Wed, 28 Jan.Return flight with British Airways.Outbound indirect flight with British Airways, departs from Ontario International on Wed, 14 Jan, arriving in London Heathrow.Inbound indirect flight with British Airways, departs from London Heathrow on Wed, 28 Jan, arriving in Ontario International.Price includes taxes and charges.From 543 €, select.
London.546 € per passenger.Departing Fri, 2 Jan, returning Sat, 28 Mar.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Fri, 2 Jan, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Sat, 28 Mar, arriving in Ontario International.Price includes taxes and charges.From 546 €, select.
London.561 € per passenger.Departing Tue, 24 Feb, returning Tue, 3 Mar.Return flight with British Airways.Outbound indirect flight with British Airways, departs from Ontario International on Tue, 24 Feb, arriving in London Heathrow.Inbound indirect flight with British Airways, departs from London Heathrow on Tue, 3 Mar, arriving in Ontario International.Price includes taxes and charges.From 561 €, select.

Find the cheapest month to fly from Ontario International to London Heathrow

We’re always keeping an eye on fares, so you can find the best one in seconds. It looks like Ontario International to London Heathrow flights are currently cheapest in October.
Aug
Find prices
Sep
from 449 €
Oct
from 448 €
Nov
from 535 €
Dec
from 533 €
Jan
from 543 €
Feb
from 497 €
Mar
from 580 €
Apr
from 571 €
May
from 575 €
Jun
from 1.011 €
Jul
from 990 €

Ontario International to London Heathrow: Alternative routes

Compare routes from Ontario International to London below. You may find an airport to fly into that's cheaper, faster, or easier than London Heathrow.

Ontario to London: Flight information

The things to know before you go.
Cheapest flight found448 €
Cheapest month to flyOctober

Finding cheap flights from Ontario International to London Heathrow: Frequently asked questions

The best price we found for a return flight from Ontario International to London Heathrow is 448 €. This is an estimate based on information collected from different airlines and travel providers over the last 4 days and is subject to change and availability.
Currently, there are no airlines that fly direct from Ontario International to London Heathrow. But we found flights with one or more stops from 448 €.
As of August 2025, there are no flights flying from Ontario International to London Heathrow.
The cheapest month to fly from Ontario International to London Heathrow is usually October.
After crunching the numbers on our flight calendar, we found that it's currently cheapest to fly from Ontario International Airport to London Heathrow Airport on Sunday, 5 October 2025.
No airlines currently offer direct flights between Ontario International Airport and London Heathrow Airport. Most routes have one or more stops.
We show every price from over 1,200 airlines and travel agents, comparing them all so you don’t have to. If you know you want to fly to London Heathrow but you’re not ready to book, set up a Price Alert. We’ll track prices for you, and let you know when they rise or fall.
We crunched all the numbers in our flight calendar and it looks like the cheapest time to book a flight to London is around 40 days in advance, so don’t leave your flight to the last minute.
Currently, KLM offers the cheapest flight tickets to London Heathrow.

Travelling from Ontario International Airport (ONT) to London Heathrow Airport (LHR): what you need to know

  • London is seven hours ahead of Ontario and observes the UTC+0 timezone.

  • Your ONT to LHR flight won't wait if you're late, so show up at the airport on time. Arrive up to one hour in advance for domestic flights and two hours ahead when you're flying internationally.

  • During popular months like August, it's a good idea to get to the airport earlier than usual. Arrive two hours before domestic departures and four hours ahead for an international flight whenever you're flying during peak periods in general.

  • If you want to add a stop to your trip, just uncheck 'Direct flights only' when searching for your ticket from Ontario International Airport to London Heathrow Airport. These are the top stopovers between ONT and LHR:

    • Harry Reid Airport (formerly McCarran Airport)

    • Denver International Airport

    • Phoenix Sky Harbour International Airport

How to find the cheapest flights from Ontario International Airport (ONT) to London Heathrow Airport (LHR)

  • The cheapest price we've seen for a one-way Ontario International Airport to London Heathrow Airport flight is 236 €. A round-trip plane ticket right now is 448 €. Depending on the availability and when you book, these fares can change.

  • It's usually smart to book ahead of time if you're hoping to get cheap tickets from ONT to LHR. That's because airlines change prices based on demand, which tends to increase closer to departure.

  • If you're flexible with your trip dates, try using the 'Whole month' search function. It'll show you the cheapest price across the month when looking for a flight from Ontario International Airport to London Heathrow Airport.

  • Picking up cheap flights from ONT to LHR is a breeze with Price Alerts. All you need to do is create one of these automatic alerts and we'll let you know as soon as a new deal comes up.

  • Secure the ideal flight for you with the help of the filters. To see the 'Cheapest,' 'Fastest' or 'Best' flights from Ontario International Airport to London Heathrow Airport, use the 'Sort by' tool. You can also filter by arrival and departure times, airline, and number of stops.

Handy information about Ontario International Airport (ONT)

  • You'll find ONT at 2900 E. Airport Drive.

  • Ontario International Airport has a strong on-time performance, so flight disruptions are less likely. Departures from ONT make it to their destination as scheduled 83.6% of the time.

  • Central Ontario to Ontario International Airport is approximately 6 kilometres. Depending on traffic, it'll take you about 10 minutes to get there if you're driving, catching a cab or ride-sharing.

  • Catching public transport? Expect a journey time of around 1 hour 30 minutes.

  • Get your travels off to a hassle-free start by staying near ONT. Whether you're taking an early flight from Ontario International Airport to London Heathrow Airport or just don't like being rushed, these hotels are the answer:

Arriving at London Heathrow Airport (LHR)

Getting from London Heathrow Airport (LHR) to central London

  • London Heathrow Airport is roughly 31 kilometres from central London. Driving there takes about 55 minutes.

  • Getting to the centre by public transport will take you roughly 1 hour.

When to fly to London Heathrow Airport (LHR)

  • It's time to work out your dates for your flight from Ontario International Airport to London Heathrow Airport. July is the most popular month to head to London. If you'd like a more laid-back vibe, go in February.

  • Lock in your flight from Ontario International Airport to London Heathrow Airport for July if you'd like to visit London during its warmest month. You can expect temperatures of between 11ºC (52ºF) and 26ºC (79ºF).

  • Look for cheap tickets from ONT to LHR in January if you'd rather travel during cooler conditions. Temperatures are at their lowest then, ranging between 0ºC (32ºF) and 9ºC (48ºF) on average.

Explore more of United Kingdom

  • London has plenty going for it, but there are so many other parts of United Kingdom just waiting to be discovered. About 161 kilometres north-west of London, a visit to Birmingham will fill your itinerary to the brim. Start with leading attractions like Cadbury World, The Library of Birmingham and National Sea Life Centre.

  • If you're ready to explore another well-known destination in United Kingdom, head for Bristol, roughly 177 kilometres west of London. Clifton Suspension Bridge, Cabot Tower and Brandon Hill Nature Park are highlights.

Plan the rest of your trip from Ontario to London

Prices shown on this page are estimated lowest prices only. Found in the last 45 days.