€434 Cheap Flights London to Ontario Intl. Airport (LHR-ONT)

Start packing your bags, because round-trip flights between London Heathrow and ONT start from €584. That's based on fares listed within the last 7 days on Expedia for flights departing within the next year. Prices can rise quickly, so book now to nab the best deal. Prices and availability are subject to change. Additional terms apply.

The majority of flights can be cancelled online, but whether you are charged a fee depends on your airline. If you do need to cancel your getaway, follow the instructions in the Customer Service Portal.

Many airlines offer the option to reschedule your flight without a change fee. All you pay is the difference between the original flight and the new flight. When you're searching for Heathrow Airport (LHR) to Ontario Airport flights, you'll see a "no change fees" filter for you to select.

Hounslow to Ontario is around 8,700 kilometres, so get ready to spend quite a while in the air. Make sure you pack all the essentials, from your hoodie to your headphones. Take some snacks to nibble on throughout your trip too.

At the moment, no airlines offer flights directly from Heathrow Airport to ONT. You'll have to book a flight with one or more stops. To score the best price and connections, lock in your airfare well ahead of time.

Last-minute bookings from Heathrow Airport (LHR) to Ontario Airport can be hit-or-miss. You may be able to find a bargain, but then again, you could miss out altogether! If you'd prefer to start planning your trip ahead of time, Expedia compares flight deals up to a year in advance. Just keep in mind that not all airlines issue their prices that far in advance. Our top tip? Check back often as prices are updated frequently.