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Cheap flights from London Heathrow Airport to Siem Reap

LHR — SAI
23 Nov — 30 Nov1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Heathrow to Siem Reap

Keep the following information in mind while searching for Heathrow to Siem Reap flight deals. Data was last updated 24 October 2025.

Popular in

December

Cheapest in

September

Average price

£778
Highest demand for flights based on searches. 5% potential increase in price (£41 potential increase over avg. return price).
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Cheapest flight prices on average. 4% potential price decrease (£28 potential savings vs. average return price).
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Average for round-trip flights in October 2025
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Cheapflights Insights

Everything you need to know about your flight from London Heathrow Airport to Siem Reap

What is the cheapest month to book a flight from London Heathrow Airport to Region of Siem Reap?

Currently, September is the cheapest month in which you can book a flight from London Heathrow Airport to Region of Siem Reap (average of £613). Flying from London Heathrow Airport to Region of Siem Reap in August is currently the most expensive (average of £901). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

Reviews of airlines servicing Siem Reap

Get insights into the airlines that provide service to Siem Reap. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Siem Reap. Reviews last updated 24 October 2025.
Get a feel of what it's like to fly with Singapore Airlines, Thai Airways, andAustrian Airlines from London Heathrow Airport to Siem Reap by reading reviews from past customers. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Singapore Airlines
8.1
Very Good
1,387 reviews
Check prices

Entertainment

8.0

Crew

8.6

Food

7.7

Boarding

8.3

Comfort

8.0

Overall

8.1

Reviews

1 / 20
10.0
Excellent

Juliet,Oct 2025

PUS - SIN

Very kind staff to arrange my luggage and really appreciate all help.
Singapore Airlines
8.1
Very Good
1,387 reviews
Singapore Airlines
8.1
Very Good
1,387 reviews
Check prices

Entertainment

8.0

Crew

8.6

Food

7.7

Boarding

8.3

Comfort

8.0

Overall

8.1

Reviews

1 / 20
10.0
Excellent

Juliet,Oct 2025

PUS - SIN

Very kind staff to arrange my luggage and really appreciate all help.
Thai Airways
7.8
Good
360 reviews
Singapore Airlines
8.1
Very Good
1,387 reviews
Check prices

Entertainment

8.0

Crew

8.6

Food

7.7

Boarding

8.3

Comfort

8.0

Overall

8.1

Reviews

1 / 20
10.0
Excellent

Juliet,Oct 2025

PUS - SIN

Very kind staff to arrange my luggage and really appreciate all help.
Austrian Airlines
7.6
Good
863 reviews
Singapore Airlines
8.1
Very Good
1,387 reviews
Check prices

Entertainment

8.0

Crew

8.6

Food

7.7

Boarding

8.3

Comfort

8.0

Overall

8.1

Reviews

1 / 20
10.0
Excellent

Juliet,Oct 2025

PUS - SIN

Very kind staff to arrange my luggage and really appreciate all help.
Vietnam Airlines
7.5
Good
207 reviews
Singapore Airlines
8.1
Very Good
1,387 reviews
Check prices

Entertainment

8.0

Crew

8.6

Food

7.7

Boarding

8.3

Comfort

8.0

Overall

8.1

Reviews

1 / 20
10.0
Excellent

Juliet,Oct 2025

PUS - SIN

Very kind staff to arrange my luggage and really appreciate all help.
Lufthansa
6.8
Okay
7,518 reviews
Singapore Airlines
8.1
Very Good
1,387 reviews
Check prices

Entertainment

8.0

Crew

8.6

Food

7.7

Boarding

8.3

Comfort

8.0

Overall

8.1

Reviews

1 / 20
10.0
Excellent

Juliet,Oct 2025

PUS - SIN

Very kind staff to arrange my luggage and really appreciate all help.

Related info for your journey

Find useful and relevant information for your journey from Heathrow to Siem Reap. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • Can I find deals for flights from Heathrow to Siem Reap that include hotel bookings?

    Yes. In addition to deals on Heathrow to Siem Reap flights, Cheapflights offers holiday packages that include both flights and hotel.

  • How can I find direct flights from Heathrow to Siem Reap?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Heathrow to Siem Reap.

  • Can I find deals for business class flights from Heathrow to Siem Reap?

    Yes. Cheapflights offers flight deals from Heathrow to Siem Reap by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from London Heathrow Airport to Region of Siem Reap?

    Currently, September is the cheapest month in which you can book a flight from London Heathrow Airport to Region of Siem Reap (average of £613). Flying from London Heathrow Airport to Region of Siem Reap in August is currently the most expensive (average of £901). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

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Top 5 airlines flying from Heathrow to Siem Reap

Discover the top 5 airlines that operate flights from Heathrow to Siem Reap. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 858,174 searches. Data last updated 24 October 2025.
AirlineCheapestAverageFlexibilityOn-time
Austrian AirlinesCheapest£586Average£695FlexibilityNo cancel feeOn-time78%
Search Austrian Airlines flights
Vietnam AirlinesCheapest£620Average£724FlexibilityNo cancel feeOn-time81%
Search Vietnam Airlines flights
Singapore AirlinesCheapest£641Average£742FlexibilityNo cancel feeOn-time81%
Search Singapore Airlines flights
LufthansaCheapest£738Average£774FlexibilityNo cancel feeOn-time76%
Search Lufthansa flights
Thai AirwaysCheapest£865Average£954FlexibilityNo cancel feeOn-time77%
Search Thai Airways flights

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travellers can enjoy low prices and a wide availability of flights to their desired destinations.

How does Cheapflights help users find flights from Heathrow to Siem Reap?

Cheapflights goes through 900+ travel sites to look for the best flight deals for flights from Heathrow to Siem Reap. Too many options? Cheapflights also provides filters for things like airlines, price ranges, and number of stops to help you make a decision easily.

Why should you use Cheapflights to find cheap flight tickets from Heathrow to Siem Reap?

Cheapflights helps you find that perfect flight to Siem Reap from Heathrow by searching from hundreds of airlines and agencies you know and love. We are also free to use, in case you were wondering!

Can Cheapflights find flights from Heathrow to Siem Reap with no change fees?

Certainly. Search results for flights to Siem Reap from Heathrow shown to you on Cheapflights can be narrowed down with different useful search filters, which includes flexible booking options.

Can Cheapflights notify me if prices for flights from Heathrow to Siem Reap become cheaper?

Yes, Cheapflights offers price alerts on Heathrow to Siem Reap flights so you can book your travel at the perfect time. Price Alerts can be enabled by clicking the bell icon next to the flight deals above and providing your email address where you want to receive the alerts.

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