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Cheap flights from London to Siem Reap from £275

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 1/10. Fares are subject to change and may not be available on all flights or dates of travel.
LON — SAI
4 Sep — 11 Sep1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from London to Siem Reap

Enter your travel dates to find the best prices.

Cheapest flights from London to Siem Reap
Explore the most affordable flight options available from London to Siem Reap. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 5 August 2026.

Thu 19/1106:00 -
2 stops29h 45m
Thu 3/1209:55 -
2 stops18h 45m
Deal found 1/8£577
Thu 3/1206:00 -
2 stops29h 45m
Mon 14/1209:55 -
2 stops29h 25m
Deal found 3/8£578
Sun 8/1106:00 -
2 stops29h 45m
Sun 22/1109:55 -
2 stops18h 45m
Deal found 2/8£596
Thu 3/1206:00 -
2 stops29h 45m
Mon 14/1209:55 -
2 stops18h 45m
Deal found 1/8£606
Tue 1/911:35 -
2 stops24h 30m
Fri 11/919:05 -
2 stops54h 10m
Deal found 1/8£613
Wed 2/909:25 -
2 stops27h 30m
Thu 1/1009:40 -
2 stops28h 45m
Deal found 1/8£614
Wed 2/913:50 -
2 stops23h 05m
Thu 1/1009:40 -
2 stops18h 05m
Deal found 1/8£615
Fri 25/906:00 -
2 stops30h 55m
Tue 29/909:40 -
2 stops28h 15m
Deal found 1/8£615
Thu 10/909:25 -
2 stops27h 30m
Wed 23/909:40 -
2 stops28h 45m
Deal found 2/8£615
Sun 20/906:00 -
2 stops30h 55m
Sat 3/1009:40 -
2 stops18h 05m
Deal found 3/8£616
Mon 16/1106:00 -
2 stops29h 45m
Mon 7/1209:55 -
2 stops40h 20m
Deal found 2/8£621
Mon 31/818:00 -
2 stops44h 10m
Fri 2/1021:10 -
2 stops52h 05m
Deal found 1/8£621

Find flight deals from London to Siem Reap

Keep the following information in mind while searching for London to Siem Reap flight deals. Data was last updated 5 August 2026.

Round-trip from

£577

One-way from

£275

Popular in

December

Cheapest in

July

Average price

£928
Austrian Airlines
  • Austrian Airlines
  • 19/11-3/12
  • 4 total stops
  • 48h 30m total
  • London to Siem Reap
Search Deals
1/10
  • 1/10
  • 3 total stops
  • 51h 00m total
  • London to Siem Reap
Search Deals
Highest demand for flights based on searches. 11% potential increase in price (£74 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease (£27 potential savings vs. average return price).
Search Deals
Average for round-trip flights in August 2026
Search Deals

Cheapflights Fare Finder

 
Customise your flight search to find flights from London to Siem Reap that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 858,174 searches. Data last updated 5 August 2026.
Use the filters below to find and compare flights from London to Siem Reap that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest return flight

LondonSiem Reap

LHR London Heathrow - SAI Siem Reap–Angkor Intl

LHRSAI

London Heathrow

Wed 18/11

13:45-18:45

2 stops22h 00m

Siem Reap–Angkor Intl

Fri 4/12

09:55-21:40

2 stops18h 45m

£641

LondonSiem Reap

LGW London Gatwick - SAI Siem Reap–Angkor Intl

LGWSAI

London Gatwick

Thu 3/9

09:25-18:55

2 stops27h 30m

Siem Reap–Angkor Intl

Fri 25/9

09:40-08:25

2 stops28h 45m

£655

LondonSiem Reap

LGW London Gatwick - SAI Siem Reap–Angkor Intl

LGWSAI

London Gatwick

Fri 20/11

10:30-21:00

3 stops27h 30m

Siem Reap–Angkor Intl

Tue 1/12

22:00-06:30

3 stops39h 30m

£671

LondonSiem Reap

LTN London Luton - SAI Siem Reap–Angkor Intl

LTNSAI

London Luton

Mon 31/8

05:40-18:05

3 stops30h 25m

Siem Reap–Angkor Intl

Thu 10/9

17:55-00:50

3 stops36h 55m

£671

LondonSiem Reap

LGW London Gatwick - SAI Siem Reap–Angkor Intl

LGWSAI

London Gatwick

Fri 20/11

10:30-21:00

3 stops27h 30m

Siem Reap–Angkor Intl

Sat 5/12

22:00-14:00

3 stops47h 00m

£671

LondonSiem Reap

LGW London Gatwick - SAI Siem Reap–Angkor Intl

LGWSAI

London Gatwick

Thu 19/11

10:30-21:00

2 stops51h 30m

Siem Reap–Angkor Intl

Tue 1/12

22:00-06:30

2 stops39h 30m

£671

LondonSiem Reap

LHR London Heathrow - SAI Siem Reap–Angkor Intl

LHRSAI

London Heathrow

Fri 20/11

19:25-18:45

2 stops16h 20m

Siem Reap–Angkor Intl

Wed 2/12

09:55-21:40

2 stops18h 45m

£677

LondonSiem Reap

LTN London Luton - SAI Siem Reap–Angkor Intl

LTNSAI

London Luton

Thu 8/10

21:40-11:15

3 stops31h 35m

Siem Reap–Angkor Intl

Fri 23/10

19:20-23:50

3 stops34h 30m

£692

LondonSiem Reap

LGW London Gatwick - SAI Siem Reap–Angkor Intl

LGWSAI

London Gatwick

Wed 2/9

18:00-20:10

2 stops44h 10m

Siem Reap–Angkor Intl

Wed 30/9

21:10-15:00

2 stops47h 50m

£721

LondonSiem Reap

LGW London Gatwick - SAI Siem Reap–Angkor Intl

LGWSAI

London Gatwick

Sun 1/11

17:00-21:00

2 stops45h 00m

Siem Reap–Angkor Intl

Sat 14/11

22:00-06:30

3 stops39h 30m

£722

Flights are sorted by cheapest return flights first.

Deals found on 5/8

Showing 1-10 of 60 resultsSorted by cheapest first
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Best time to book a flight from London to Siem Reap

Have a flexible travel schedule? Discover the best time to fly to Siem Reap from London with our price prediction graph.
Estimated return price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

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

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

Currently, March is the cheapest month in which you can book a flight from London to Region of Siem Reap (average of £689). Flying from London to Region of Siem Reap in December is currently the most expensive (average of £972). 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.

How much does it cost for a return flight from London to Region of Siem Reap?

Airfare is below average for this route at the moment.
London to Region of Siem Reap flights typically cost between £905 and £1,083 in November.
The cheapest return price found within the last 5 days was £577 on Austrian Airlines (19 Nov–3 Dec).

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 5 August 2026.
Check out reviews from past customers who have flown with Singapore Airlines,Thai Airways, andVietnam Airlines from London to Siem Reap to help guide your decision. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Singapore Airlines
8.2
Very Good
1,584 reviews
Check prices

Boarding

8.3

Comfort

8.0

Overall

8.2

Crew

8.6

Food

7.8

Entertainment

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

DAD - SIN

Person in front laid back his seat. I’m quite tall found it difficult to sit straight lucky seat next to me was empty was able to stretch my legs. Eating my meal was difficult also as seat remained lowered
Singapore Airlines
8.2
Very Good
1,584 reviews
Singapore Airlines
8.2
Very Good
1,584 reviews
Check prices

Boarding

8.3

Comfort

8.0

Overall

8.2

Crew

8.6

Food

7.8

Entertainment

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

DAD - SIN

Person in front laid back his seat. I’m quite tall found it difficult to sit straight lucky seat next to me was empty was able to stretch my legs. Eating my meal was difficult also as seat remained lowered
Thai Airways
7.9
Good
413 reviews
Singapore Airlines
8.2
Very Good
1,584 reviews
Check prices

Boarding

8.3

Comfort

8.0

Overall

8.2

Crew

8.6

Food

7.8

Entertainment

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

DAD - SIN

Person in front laid back his seat. I’m quite tall found it difficult to sit straight lucky seat next to me was empty was able to stretch my legs. Eating my meal was difficult also as seat remained lowered
Vietnam Airlines
7.7
Good
283 reviews
Singapore Airlines
8.2
Very Good
1,584 reviews
Check prices

Boarding

8.3

Comfort

8.0

Overall

8.2

Crew

8.6

Food

7.8

Entertainment

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

DAD - SIN

Person in front laid back his seat. I’m quite tall found it difficult to sit straight lucky seat next to me was empty was able to stretch my legs. Eating my meal was difficult also as seat remained lowered
British Airways
6.7
Okay
8,147 reviews
Singapore Airlines
8.2
Very Good
1,584 reviews
Check prices

Boarding

8.3

Comfort

8.0

Overall

8.2

Crew

8.6

Food

7.8

Entertainment

8.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

DAD - SIN

Person in front laid back his seat. I’m quite tall found it difficult to sit straight lucky seat next to me was empty was able to stretch my legs. Eating my meal was difficult also as seat remained lowered

Related info for your journey

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

  • How long is the flight from London to Region of Siem Reap?

    A quick flight from London to Region of Siem Reap can take about 24h 35m. SWISS provides one of the quickest options available for as low as £802. London and Region of Siem Reap are separated by a distance of 6068 mi. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.

  • What are the cheapest airlines to fly from London to Region of Siem Reap one-way?

    For one-way options, check prices for Vietnam Airlines. According to our data, you can fly for as low as £452. Users have also found prices from £556 and £558 on Singapore Airlines and Thai Airways, respectively.

  • What are the most popular routes from London to Region of Siem Reap?

    Most travelers choose London Heathrow - Siem Reap–Angkor Intl, London Gatwick - Siem Reap–Angkor Intl or London City - Siem Reap–Angkor Intl when deciding on the best route from London to Region of Siem Reap.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from London 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 to Region of Siem Reap?

    Currently, March is the cheapest month in which you can book a flight from London to Region of Siem Reap (average of £689). Flying from London to Region of Siem Reap in December is currently the most expensive (average of £972). 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 4 airlines flying from London to Siem Reap

Discover the top 4 airlines that operate flights from London 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 5 August 2026.
AirlineCheapestAverageFlexibilityOn-time
Austrian AirlinesCheapest£554Average£687FlexibilityNo cancel feeOn-time78%
Search Austrian Airlines flights
Vietnam AirlinesCheapest£616Average£815FlexibilityNo cancel feeOn-time81%
Search Vietnam Airlines flights
Singapore AirlinesCheapest£664Average£921FlexibilityNo cancel feeOn-time81%
Search Singapore Airlines flights
Thai AirwaysCheapest£889Average£1,022FlexibilityNo 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 London to Siem Reap?

Cheapflights goes through 900+ travel sites to look for the best flight deals for flights from London 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 London to Siem Reap?

Cheapflights taps into our reliable network of hundreds of airlines and travel agencies to find the best deals for flights from London to Siem Reap for you. Better yet — we are completely free to use.

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

Users can book flights with no change fees policies with our dedicated filters. Book flights from London to Siem Reap flexibly with Cheapflights today.

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

Yes, Cheapflights has a feature called Price Alert, which notifies users when flight prices change. Track prices for your flight to Siem Reap from London today and book when prices fit your budget.

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