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Cheap Flights from Ontario (ONT) to London (LHR)

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      Travellers and cabin class, 1 Adult, Economy

      Compare Ontario International to London Heathrow flight deals

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

      Book the best London Heathrow fare with no extra fees

      Flight deals from Ontario International to London Heathrow

      Looking for a cheap last-minute deal or the best return flight from Ontario International Airport to London Heathrow Airport? If you want to travel next month, return fares start from $1,029. Find the lowest prices on one-way and return tickets right here.
      London.$1,027 per passenger.Departing Wed, 25 Nov, returning Thu, 3 Dec.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Wed, 25 Nov, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Thu, 3 Dec, arriving in Ontario International.Price includes taxes and charges.From $1,027, select.
      London.$1,027 per passenger.Departing Tue, 10 Nov, returning Tue, 17 Nov.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Tue, 10 Nov, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Tue, 17 Nov, arriving in Ontario International.Price includes taxes and charges.From $1,027, select.
      London.$1,028 per passenger.Departing Tue, 27 Oct, returning Tue, 3 Nov.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Tue, 27 Oct, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Tue, 3 Nov, arriving in Ontario International.Price includes taxes and charges.From $1,028, select.
      London.$1,029 per passenger.Departing Mon, 5 Oct, returning Wed, 14 Oct.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Mon, 5 Oct, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Wed, 14 Oct, arriving in Ontario International.Price includes taxes and charges.From $1,029, select.
      London.$1,030 per passenger.Departing Tue, 22 Sep, returning Tue, 29 Sep.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Tue, 22 Sep, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Tue, 29 Sep, arriving in Ontario International.Price includes taxes and charges.From $1,030, select.
      London.$1,030 per passenger.Departing Wed, 2 Dec, returning Wed, 9 Dec.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Wed, 2 Dec, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Wed, 9 Dec, arriving in Ontario International.Price includes taxes and charges.From $1,030, select.
      London.$1,033 per passenger.Departing Mon, 5 Apr, returning Wed, 14 Apr.Return flight with Air France and KLM.Outbound indirect flight with Air France, departs from Ontario International on Mon, 5 Apr, arriving in London Heathrow.Inbound indirect flight with KLM, departs from London Heathrow on Wed, 14 Apr, arriving in Ontario International.Price includes taxes and charges.From $1,033, select.
      London.$1,035 per passenger.Departing Wed, 28 Apr, returning Wed, 5 May.Return flight with Alaska Airlines.Outbound indirect flight with Alaska Airlines, departs from Ontario International on Wed, 28 Apr, arriving in London Heathrow.Inbound indirect flight with Alaska Airlines, departs from London Heathrow on Wed, 5 May, arriving in Ontario International.Price includes taxes and charges.From $1,035, select.
      London.$1,043 per passenger.Departing Tue, 12 Jan, returning Wed, 10 Feb.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Tue, 12 Jan, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Wed, 10 Feb, arriving in Ontario International.Price includes taxes and charges.From $1,043, select.
      London.$1,091 per passenger.Departing Sat, 1 May, returning Wed, 5 May.Return flight with Alaska Airlines.Outbound indirect flight with Alaska Airlines, departs from Ontario International on Sat, 1 May, arriving in London Heathrow.Inbound indirect flight with Alaska Airlines, departs from London Heathrow on Wed, 5 May, arriving in Ontario International.Price includes taxes and charges.From $1,091, select.
      London.$1,096 per passenger.Departing Sat, 6 Mar, returning Fri, 19 Mar.Return flight with Alaska Airlines.Outbound indirect flight with Alaska Airlines, departs from Ontario International on Sat, 6 Mar, arriving in London Heathrow.Inbound indirect flight with Alaska Airlines, departs from London Heathrow on Fri, 19 Mar, arriving in Ontario International.Price includes taxes and charges.From $1,096, select.
      London.$1,098 per passenger.Departing Thu, 15 Oct, returning Thu, 4 Feb.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Thu, 15 Oct, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Thu, 4 Feb, arriving in Ontario International.Price includes taxes and charges.From $1,098, select.
      London.$1,107 per passenger.Departing Sun, 17 Jan, returning Mon, 25 Jan.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Sun, 17 Jan, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Mon, 25 Jan, arriving in Ontario International.Price includes taxes and charges.From $1,107, select.
      London.$1,125 per passenger.Departing Wed, 3 Feb, returning Sun, 7 Feb.Return flight with Air France and KLM.Outbound indirect flight with Air France, departs from Ontario International on Wed, 3 Feb, arriving in London Heathrow.Inbound indirect flight with KLM, departs from London Heathrow on Sun, 7 Feb, arriving in Ontario International.Price includes taxes and charges.From $1,125, select.
      London.$1,165 per passenger.Departing Tue, 1 Dec, returning Sat, 9 Jan.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Tue, 1 Dec, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Sat, 9 Jan, arriving in Ontario International.Price includes taxes and charges.From $1,165, select.
      London.$1,167 per passenger.Departing Fri, 25 Sep, returning Sat, 3 Oct.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Fri, 25 Sep, arriving in London Heathrow.Inbound indirect flight with Delta, departs from London Heathrow on Sat, 3 Oct, arriving in Ontario International.Price includes taxes and charges.From $1,167, select.
      How did we find these deals? The deals you see here are the lowest prices for flight tickets from Ontario International to London Heathrow found in the last 4 days, and are subject to change and availability.

      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 November.
      Sep
      from $1,030
      Oct
      from $1,029
      Nov
      from $1,027
      Dec
      from $1,030
      Jan
      from $1,107
      Feb
      from $1,125
      Mar
      from $1,096
      Apr
      from $1,033
      May
      from $1,091
      Jun
      from $1,714
      Jul
      from $2,285
      Aug
      Find prices

      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.

      London City

      12km from central London
      Closest
      from $1,191
      Search flights

      London Heathrow

      23km from central London
      Cheapest
      from $1,027
      Search flights

      London Gatwick

      40km from central London
      from $1,054
      Search flights

      London Luton

      45km from central London
      Search flights

      London Stansted

      49km from central London
      from $1,765
      Search flights

      London Southend

      57km from central London
      Search flights

      Ontario to London: Flight information

      The things to know before you go.
      Cheapest flight found$1,027
      Cheapest month to flyNovember

      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 $1,027. 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 $1,027.
      As of September 2026, there are no flights flying from Ontario International to London Heathrow.
      The cheapest month to fly from Ontario International to London Heathrow is usually November.
      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 Tuesday, 10 November 2026.
      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, Delta 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's timezone is UTC+0, making London eight hours ahead of Ontario.

      • Get to the airport on time so you don't miss your ONT to LHR flight. Be there at least two hours ahead for international flights and an hour early for domestic departures to avoid sprinting to your gate.

      • You can expect bigger queues during popular months such as July. Arriving up to four hours ahead of an international flight and two hours for domestic departures is a wise move.

      • Consider adding a stopover when booking your ticket from Ontario International Airport to London Heathrow Airport. Simply deselect 'Direct flights only' to break up your trip, or perhaps explore a new destination along the way. Here's where you can stop between ONT and LHR:

        • Denver International Airport

        • Phoenix Sky Harbour Airport

        • Harry Reid International Airport

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

      • The cheapest price we've found for a one-way Ontario International Airport to London Heathrow Airport flight is $432. A return plane ticket right now is $1,027. Depending on the availability and when you book, these fares may change.

      • To get your hands on cheap tickets from ONT to LHR, book in advance. Airlines usually offer their best fares when flights are first released.

      • The 'Whole month' search function shows you the cheapest flights from Ontario International Airport to London Heathrow Airport across the month. It's a good way to find a bargain if your plans aren't set in stone.

      • Landing cheap flights from ONT to LHR is easy with Price Alerts. Simply create one of these automatic alerts and we'll let you know when a lower fare pops up.

      • Tailor your trip with filters. Select your ideal departure and arrival times, airlines and total journey duration. You can also sort results by 'Cheapest,' 'Best' or 'Fastest' flights from Ontario International Airport to London Heathrow Airport.

      Handy information about Ontario International Airport (ONT)

      • ONT is located at 2900 E. Airport Drive.

      • Ontario International Airport has an excellent on-time performance, so flight disruptions are less likely. Departures from ONT make it to their destination as scheduled 83% of the time.

      • To reach Ontario International Airport from central Ontario, it takes about 15 minutes if you're travelling by car. Of course, this depends on traffic. It's approximately 10 kilometres from the airport to the city centre.

      • Expect a trip time of around 45 minutes on public transport.

      • Catching an early flight from Ontario International Airport to London Heathrow Airport? Avoid rushing to the airport (and catch some extra z's) by choosing one of these stays near ONT:

      Arriving at London Heathrow Airport (LHR)

      When to fly to London Heathrow Airport (LHR)

      • It's time to plan your dates for your flight from Ontario International Airport to London Heathrow Airport. July is the most popular month to visit London. If you want a more relaxed vibe, go in March.

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

      • For cooler conditions, look for a cheap ticket from ONT to LHR in January. Average temperatures are between 0ºC (32ºF) and 9ºC (48ºF) then.

      Explore more of the United Kingdom

      • London has plenty going for it, but there are so many other corners of the United Kingdom waiting to be explored. About 257 kilometres north-west of London, a visit to Manchester will keep you on the go. Don't miss top attractions like Manchester United Museum & Stadium Tour, The Homes of Football and Museum of Science and Industry.

      • Around 161 kilometres north-west of London, Birmingham is another essential stop in the United Kingdom. Experience major highlights starting with Birmingham Museum & Art Gallery, Birmingham Hippodrome Theatre and Bournville Experience.

      Plan smart, explore more

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      Plan the rest of your trip from Ontario to London

      Prices shown on this page are estimated lowest prices only. Found in the last 12 days.