Cheap Flights London to Siem Reap from £473

Flight FAQs

• Which airlines offer the cheapest flights from London to Siem Reap?

  Based on Trip.com data, Vietnam Airlines offers Cheapest nonstop one-way flights from £473 (for example, LHR–SAI on Sat, Sep 12). For a Cheapest nonstop return flight, British Airways offers fares from £753, departing on Sat, Nov 7 and returning on Sat, Nov 14.

• Which airlines offer direct flights from London to Siem Reap?

  At the moment, you can catch a direct flight from London to Siem Reap with the following airlines, including: Ryanair Selected airlines are based on historical data collected from flight bookings users made on Trip.com within the last 90 days.

• When is the best time to book flights from London to Siem Reap?

  By analyzing data from all airlines on the Trip.com flight calendar, it looks like the best time to book a flight from London to Siem Reap is around 40 days (6 weeks) in advance, and the best time to fly is usually on Tuesday, Wednesday, and Saturday. Tuesday typically offers the cheapest flights for departure, while Saturday offers the best return deals.

• How can I find the best deals on flights from London to Siem Reap?

  Here are some tips for finding the best flight deals from London to Siem Reap on Trip.com:
  · Be flexible with your travel dates. The cheapest flight is currently on Sat, Sep 12, with one-way fares from just £473.
  · Compare airlines. Vietnam Airlines currently offers the lowest fares on this route.
  · Set up a price alert to track fare changes without searching every day.
  · Check Trip.com regularly for flight deals and available promo codes.
  · Get exclusive promo codes on the Trip.com app.

• Which upcoming date is the cheapest for flights from London to Siem Reap?

  After crunching the numbers on our September flight calendar, it's currently cheapest to fly from London to Siem Reap on September 22, 2026 with Vietnam Airlines, with prices starting at £466.

• Which airports should you choose for flights from London to Siem Reap?

  Flights to Siem Reap can arrive at: Siem Reap Angkor International Airport (SAI). The most common route connects Heathrow Airport and Siem Reap Angkor International Airport (LHR–SAI).

• What is the time difference between London and Siem Reap?

  The time difference between Siem Reap and London is 7h.

• How can I change or cancel my flight ticket from London to Siem Reap?

  Tickets can only be changed or cancelled if permitted by airline policy. To submit a change or cancellation request, go to the flight bookings page, select the option to change or cancel your booking, choose the relevant passengers and segment, and submit a request. Please note that additional charges may apply according to the airline ticket policy. However, if the flight has been rescheduled and you would like to change or cancel your ticket, you can submit an involuntary cancellation request. For more details about change and cancellation policies, please check the customer support pages.

• What is the average price of a one-way flight from London to Siem Reap?

  Based on Trip.com data for flights departing in the next 30 days, the average one-way fare from London to Siem Reap is £729. Fares vary by travel date, airline and availability.

• How do I book flights from London to Siem Reap on Trip.com?

  Enter London and Siem Reap, choose your travel dates and passengers, then compare flights by price, duration and baggage. Select a fare, review the change and cancellation rules, enter traveller details and complete payment to receive your confirmation.

• Are there budget airlines on the London to Siem Reap route?

  Ryanairare the most popular budget airlines flying from London to Siem Reap. Check baggage, seat and payment fees before comparing the final price.