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Cheap flights from London to Siem Reap, Cambodia from £284

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 17/3. Fares are subject to change and may not be available on all flights or dates of travel.
LON — SAI
6 Apr — 13 Apr1
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 7 March 2026.

Tue 8/913:50
LHR
-
SAI
2 stops22h 55m
SWISS
Wed 16/909:40
SAI
-
LHR
2 stops28h 15m
SWISS
Deal found 4/3£539
Wed 16/912:20
LHR
-
SAI
2 stops24h 25m
Multiple Airlines
Wed 30/909:40
SAI
-
LHR
2 stops18h 05m
Multiple Airlines
Deal found 5/3£543
Sun 8/1109:00
LHR
-
SAI
2 stops41h 50m
SWISS
Wed 25/1109:55
SAI
-
LHR
2 stops18h 45m
SWISS
Deal found 3/3£555
Tue 8/909:25
LGW
-
SAI
2 stops27h 20m
SWISS
Wed 16/909:40
SAI
-
LGW
2 stops28h 45m
SWISS
Deal found 4/3£559
Mon 16/1118:40
LHR
-
SAI
2 stops32h 10m
SWISS
Mon 30/1116:45
SAI
-
LHR
2 stops22h 20m
SWISS
Deal found 4/3£560
Wed 16/910:25
LGW
-
SAI
2 stops22h 25m
Multiple Airlines
Wed 14/1010:00
SAI
-
LGW
2 stops27h 30m
Multiple Airlines
Deal found 5/3£564
Wed 16/909:15
LCY
-
SAI
2 stops27h 30m
SWISS
Wed 30/909:40
SAI
-
LCY
2 stops29h 00m
SWISS
Deal found 5/3£564
Fri 20/1118:40
LHR
-
SAI
2 stops32h 10m
SWISS
Mon 30/1116:45
SAI
-
LHR
2 stops22h 20m
SWISS
Deal found 2/3£565
Fri 6/1109:25
LGW
-
SAI
2 stops22h 35m
Multiple Airlines
Fri 20/1110:10
SAI
-
LGW
2 stops27h 15m
Multiple Airlines
Deal found 4/3£565
Wed 25/1118:40
LHR
-
SAI
2 stops32h 10m
SWISS
Wed 9/1209:55
SAI
-
LHR
2 stops18h 45m
SWISS
Deal found 4/3£568
Tue 20/1011:35
LGW
-
SAI
2 stops43h 40m
Multiple Airlines
Thu 19/1122:00
SAI
-
LGW
3 stops39h 30m
Multiple Airlines
Deal found 5/3£582
Tue 20/1018:40
LHR
-
SAI
2 stops33h 00m
SWISS
Thu 19/1116:45
SAI
-
LHR
2 stops22h 20m
SWISS
Deal found 5/3£590

Find flight deals from London to Siem Reap

Discover tips and strategies to find the most affordable flight options for your journey from London (LON) to Siem Reap (SAI). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated 7 March 2026.

Round-trip from

£610

One-way from

£284

Popular in

December

Cheapest in

September

Average price

£839
China Eastern
  • China Eastern
  • 5/4-1/5
  • 5 total stops
  • 116h 20m total
  • London to Siem Reap
Search Deals
17/3
  • 17/3
  • 3 total stops
  • 52h 30m total
  • London to Siem Reap
Search Deals
Highest demand for flights based on searches. 7% potential increase in price (£49 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease (£24 potential savings vs. average return price).
Search Deals
Average for round-trip flights in March 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 7 March 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 - SAI

LHRSAI

London Heathrow

Mon 20/4

18:55-17:10

1 stop16h 15m

Siem Reap–Angkor Intl

Mon 4/5

19:10-17:50

1 stop28h 40m

£782

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Fri 1/5

11:20-09:40

1 stop16h 20m

Siem Reap–Angkor Intl

Wed 27/5

10:30-08:00

1 stop27h 30m

£803

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Sun 5/4

21:45-10:50

2 stops31h 05m

Siem Reap–Angkor Intl

Sun 3/5

13:00-07:00

2 stops48h 00m

£803

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Thu 19/3

08:50-15:15

2 stops23h 25m

Siem Reap–Angkor Intl

Sun 5/4

19:30-12:45

2 stops23h 15m

£824

LondonSiem Reap

LGW - SAI

LGWSAI

London Gatwick

Sat 16/5

09:00-18:45

2 stops27h 45m

Siem Reap–Angkor Intl

Sat 30/5

19:30-13:25

2 stops23h 55m

£912

LondonSiem Reap

STN - SAI

STNSAI

London Stansted

Sat 4/4

21:05-12:15

2 stops33h 10m

Siem Reap–Angkor Intl

Thu 30/4

23:50-18:45

2 stops24h 55m

£998

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Sun 5/4

19:50-18:10

2 stops40h 20m

Siem Reap–Angkor Intl

Sun 3/5

18:05-17:05

1 stop29h 00m

£999

LondonSiem Reap

LGW - SAI

LGWSAI

London Gatwick

Mon 10/8

10:15-09:40

1 stop17h 25m

Siem Reap–Angkor Intl

Mon 24/8

10:30-06:55

1 stop26h 25m

£1,070

LondonSiem Reap

LGW - SAI

LGWSAI

London Gatwick

Sun 5/4

14:55-18:45

2 stops21h 50m

Siem Reap–Angkor Intl

Sun 3/5

19:30-13:25

2 stops23h 55m

£1,088

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Tue 11/8

19:50-18:20

1 stop16h 30m

Siem Reap–Angkor Intl

Sun 23/8

19:10-17:05

2 stops27h 55m

£1,089

Flights are sorted by cheapest return flights first.

Deals found on 4/3

Showing 1-10 of 56 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 Siem Reap?

Currently, March is the cheapest month in which you can book a flight from London to Siem Reap (average of £586). Flying from London to Siem Reap in August is currently the most expensive (average of £1,046). 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 Siem Reap?

What’s the top stopover airport for flights from London to Siem Reap?

Share of one-stop return flights from London to Siem Reap chosen by Cheapflights users in the past 12 months, using the same stopover each way.

Singapore (SIN) – chosen by Cheapflights users on 71% of one-stop itineraries from London to Siem Reap on Cheapflights.

What’s the cheapest stopover airport for flights from London to Siem Reap?

Average return fare for one-stop flights from London to Siem Reap, chosen by Cheapflights users in the past 12 months, with the same stopover each way.

Hanoi (HAN) is the most affordable one-stop option, with an average return flight price of £709.

What’s the fastest stopover option from London to Siem Reap?

Shortest average travel time for one-stop one-way flights from London to Siem Reap, based on itineraries clicked by Cheapflights users over the past 12 months, grouped by stopover airport.

Flights via Bangkok (BKK) have the shortest average one-way travel time for one-stop routes: 14h 01m.

Which airport typically offers the quickest stopover for flights from London to Siem Reap?

Average stopover duration for one-stop one-way flights from London to Siem Reap, chosen by Cheapflights users in the last 12 months, grouped by stopover airport.

Flights via Bangkok (BKK) offer the fastest connection on this route, with an average stopover time of 1h 55m.

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 7 March 2026.
Read through reviews of airlines operating flights from London to Siem Reap, such as Singapore Airlines, Thai Airways, andVietnam Airlines. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Singapore Airlines
8.2
Very Good
1,470 reviews
Check prices

Boarding

8.3

Overall

8.2

Crew

8.6

Food

7.8

Entertainment

8.0

Comfort

8.0

Reviews

1 / 20
6.0
Good

Anonymous,Feb 2026

SAI - SIN

The only issue we had was seat selection. Was not easy to change, after they assigned seats. Also, the premium economy seats, are nothing special.. All and all safe flight with minor back issues.
Singapore Airlines
8.2
Very Good
1,470 reviews
Singapore Airlines
8.2
Very Good
1,470 reviews
Check prices

Boarding

8.3

Overall

8.2

Crew

8.6

Food

7.8

Entertainment

8.0

Comfort

8.0

Reviews

1 / 20
6.0
Good

Anonymous,Feb 2026

SAI - SIN

The only issue we had was seat selection. Was not easy to change, after they assigned seats. Also, the premium economy seats, are nothing special.. All and all safe flight with minor back issues.
Thai Airways
7.8
Good
391 reviews
Singapore Airlines
8.2
Very Good
1,470 reviews
Check prices

Boarding

8.3

Overall

8.2

Crew

8.6

Food

7.8

Entertainment

8.0

Comfort

8.0

Reviews

1 / 20
6.0
Good

Anonymous,Feb 2026

SAI - SIN

The only issue we had was seat selection. Was not easy to change, after they assigned seats. Also, the premium economy seats, are nothing special.. All and all safe flight with minor back issues.
Vietnam Airlines
7.7
Good
237 reviews
Singapore Airlines
8.2
Very Good
1,470 reviews
Check prices

Boarding

8.3

Overall

8.2

Crew

8.6

Food

7.8

Entertainment

8.0

Comfort

8.0

Reviews

1 / 20
6.0
Good

Anonymous,Feb 2026

SAI - SIN

The only issue we had was seat selection. Was not easy to change, after they assigned seats. Also, the premium economy seats, are nothing special.. All and all safe flight with minor back issues.
British Airways
6.7
Okay
7,779 reviews
Singapore Airlines
8.2
Very Good
1,470 reviews
Check prices

Boarding

8.3

Overall

8.2

Crew

8.6

Food

7.8

Entertainment

8.0

Comfort

8.0

Reviews

1 / 20
6.0
Good

Anonymous,Feb 2026

SAI - SIN

The only issue we had was seat selection. Was not easy to change, after they assigned seats. Also, the premium economy seats, are nothing special.. All and all safe flight with minor back issues.

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.

  • What airport do you fly into for flights to Siem Reap from London?

    Located just 24.7 mi from the city center, Siem Reap–Angkor Intl is the airport most travelers will use when flying to Siem Reap from London. Booking flights from London to Siem Reap–Angkor Intl (SAI) should be relatively easy as there are 0 daily inbound flights from London from 5 different airlines.

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

    A quick flight from London to Siem Reap can take about 16h 15m. Vietnam Airlines provides one of the quickest options available for as low as £782. London and Siem Reap are separated by a distance of 6106 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 flying from London to Siem Reap round-trip?

    Our cheapest airline available from London to Siem Reap is Austrian Airlines. Our recent data shows that you can find tickets from as low as £542 on this airline. Additional options worth looking into are Lufthansa and Vietnam Airlines, starting at £601 and £620 round-trip. Austrian Airlines is priced at 36% lower than the current average price of a flight leaving 3 months from now.

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

    When deciding which route to take from London to Siem Reap consider London Heathrow - Siem Reap–Angkor Intl, London Gatwick - Siem Reap–Angkor Intl or London City - Siem Reap–Angkor Intl as they are the most popular.

  • 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 Siem Reap?

    Currently, March is the cheapest month in which you can book a flight from London to Siem Reap (average of £586). Flying from London to Siem Reap in August is currently the most expensive (average of £1,046). 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 London to Siem Reap

Discover the top 5 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 7 March 2026.
AirlineCheapestAverageFlexibilityOn-time
Austrian AirlinesCheapest£542Average£693FlexibilityNo cancel feeOn-time78%
Search Austrian Airlines flights
LufthansaCheapest£601Average£772FlexibilityNo cancel feeOn-time76%
Search Lufthansa flights
Vietnam AirlinesCheapest£620Average£739FlexibilityNo cancel feeOn-time81%
Search Vietnam Airlines flights
Singapore AirlinesCheapest£667Average£907FlexibilityNo cancel feeOn-time81%
Search Singapore Airlines flights
Thai AirwaysCheapest£863Average£918FlexibilityNo 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?

When you search for this flight from London to Siem Reap, Cheapflights searches on 900+ travel sites to save you time finding great flight deals online. Additionally, we offer filter features so you can choose a preferred cabin class or airline, see different price ranges, and much more so you can book the flight for you.

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

Cheapflights helps you find that perfect flight to Siem Reap from London 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 London to Siem Reap with no change fees?

Need flexible booking options for your flight to Siem Reap from London? Don’t worry, Cheapflights have you covered. Use our search filter to only show flights with no change fees.

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

Of course! You can now track prices for flights from London to Siem Reap and get an alert from Cheapflights when they change. Have a valid email address ready and click the bell icon next to the flight deals above to set up your price alerts.

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