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Cheap flights from London to Siem Reap from £351

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 10/3. Fares are subject to change and may not be available on all flights or dates of travel.
LON — SAI
18 Mar — 25 Mar1
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 16 February 2026.

Mon 8/609:15
LGW
-
SAI
2 stops27h 30m
SWISS
Sun 14/616:00
SAI
-
LGW
2 stops22h 25m
SWISS
Deal found 13/2£551
Mon 8/608:40
LHR
-
SAI
2 stops28h 05m
SWISS
Sun 14/616:00
SAI
-
LHR
2 stops21h 55m
SWISS
Deal found 13/2£567
Tue 17/1119:25
LHR
-
SAI
2 stops16h 20m
Multiple Airlines
Tue 8/1209:55
SAI
-
LHR
2 stops18h 45m
Multiple Airlines
Deal found 15/2£583
Mon 16/1118:40
LHR
-
SAI
2 stops32h 10m
SWISS
Mon 7/1209:55
SAI
-
LHR
2 stops18h 45m
SWISS
Deal found 15/2£584
Tue 17/1119:25
LHR
-
SAI
2 stops16h 20m
Austrian Airlines
Mon 7/1209:55
SAI
-
LHR
2 stops18h 45m
Austrian Airlines
Deal found 15/2£600
Sun 15/1117:00
LGW
-
SAI
3 stops45h 00m
China Eastern
Thu 10/1222:00
SAI
-
LGW
3 stops47h 00m
China Eastern
Deal found 15/2£610
Thu 7/518:55
LHR
-
SAI
1 stop17h 15m
Vietnam Airlines
Sun 31/518:05
SAI
-
LHR
1 stop29h 00m
Vietnam Airlines
Deal found 15/2£652
Sun 15/1119:05
LCY
-
SAI
2 stops31h 45m
SWISS
Tue 8/1209:55
SAI
-
LCY
2 stops29h 45m
SWISS
Deal found 15/2£652
Fri 31/710:25
LGW
-
SAI
1 stop21h 45m
Multiple Airlines
Fri 14/814:55
SAI
-
LGW
1 stop22h 30m
Multiple Airlines
Deal found 12/2£655
Mon 8/619:15
LCY
-
SAI
2 stops41h 30m
Multiple Airlines
Sun 14/616:00
SAI
-
LCY
2 stops22h 40m
Multiple Airlines
Deal found 13/2£657
Sun 15/1117:00
LGW
-
SAI
3 stops45h 00m
China Eastern
Tue 8/1222:00
SAI
-
LGW
3 stops39h 30m
China Eastern
Deal found 15/2£660
Mon 16/1109:50
LCY
-
SAI
2 stops41h 00m
Multiple Airlines
Mon 7/1209:55
SAI
-
LCY
2 stops38h 10m
Multiple Airlines
Deal found 15/2£660

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 16 February 2026.

Round-trip from

£551

One-way from

£351

Popular in

December

Cheapest in

September

Average price

£805
SWISS
  • SWISS
  • 8/6-14/6
  • 4 total stops
  • 49h 55m total
  • London to Siem Reap
Search Deals
10/3
  • 10/3
  • 3 total stops
  • 36h 00m total
  • London to Siem Reap
Search Deals
Highest demand for flights based on searches. 7% potential increase in price (£51 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease (£23 potential savings vs. average return price).
Search Deals
Average for round-trip flights in February 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 16 February 2026.
Use the filters below to find and compare flights from London to Siem Reap that are best for you.

Fly from

London

Fly to

Siem Reap

Route

Depart

Return

Price

LondonSiem Reap

LGW - SAI

LGWSAI

London Gatwick

Mon 8/6

09:15-18:45

2 stops27h 30m

Siem Reap–Angkor Intl

Sun 14/6

16:00-08:25

2 stops22h 25m

£551

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Mon 8/6

08:40-18:45

2 stops28h 05m

Siem Reap–Angkor Intl

Sun 14/6

16:00-07:55

2 stops21h 55m

£567

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Thu 7/5

18:55-18:10

1 stop17h 15m

Siem Reap–Angkor Intl

Sun 31/5

18:05-17:05

1 stop29h 00m

£652

LondonSiem Reap

LGW - SAI

LGWSAI

London Gatwick

Fri 31/7

10:25-14:10

1 stop21h 45m

Siem Reap–Angkor Intl

Fri 14/8

14:55-07:25

1 stop22h 30m

£655

LondonSiem Reap

LCY - SAI

LCYSAI

London City

Mon 8/6

19:15-18:45

2 stops41h 30m

Siem Reap–Angkor Intl

Sun 14/6

16:00-08:40

2 stops22h 40m

£657

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Mon 8/6

18:55-17:10

1 stop16h 15m

Siem Reap–Angkor Intl

Sun 14/6

18:05-17:05

1 stop29h 00m

£661

LondonSiem Reap

LGW - SAI

LGWSAI

London Gatwick

Mon 8/6

10:15-09:40

1 stop17h 25m

Siem Reap–Angkor Intl

Sun 14/6

10:30-06:55

1 stop26h 25m

£671

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Wed 18/3

21:00-21:00

3 stops65h 00m

Siem Reap–Angkor Intl

Mon 30/3

21:10-18:40

2 stops51h 30m

£674

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Thu 26/2

10:40-09:50

1 stop16h 10m

Siem Reap–Angkor Intl

Fri 3/4

16:00-05:55

1 stop19h 55m

£679

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Thu 7/5

19:30-18:45

2 stops17h 15m

Siem Reap–Angkor Intl

Sun 31/5

19:30-08:20

2 stops18h 50m

£680

Flights are sorted by cheapest return flights first.

Deals found on 15/2

Showing 1-10 of 60 results
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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 £572). Flying from London to Region of Siem Reap in August is currently the most expensive (average of £879). 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?

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 16 February 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
1,456 reviews
Check prices

Comfort

8.0

Overall

8.2

Food

7.8

Crew

8.6

Entertainment

8.0

Boarding

8.3

Reviews

1 / 20
10.0
Excellent

Wee Keng,Dec 2025

HKG - SIN

Quick 3 hour flight with excellent service from the crew despite it being Christmas Day holiday. Ground crew passed out Xmas cookies as well. Great experience.
Singapore Airlines
8.2
Very Good
1,456 reviews
Singapore Airlines
8.2
Very Good
1,456 reviews
Check prices

Comfort

8.0

Overall

8.2

Food

7.8

Crew

8.6

Entertainment

8.0

Boarding

8.3

Reviews

1 / 20
10.0
Excellent

Wee Keng,Dec 2025

HKG - SIN

Quick 3 hour flight with excellent service from the crew despite it being Christmas Day holiday. Ground crew passed out Xmas cookies as well. Great experience.
Thai Airways
7.8
Good
382 reviews
Singapore Airlines
8.2
Very Good
1,456 reviews
Check prices

Comfort

8.0

Overall

8.2

Food

7.8

Crew

8.6

Entertainment

8.0

Boarding

8.3

Reviews

1 / 20
10.0
Excellent

Wee Keng,Dec 2025

HKG - SIN

Quick 3 hour flight with excellent service from the crew despite it being Christmas Day holiday. Ground crew passed out Xmas cookies as well. Great experience.
Vietnam Airlines
7.6
Good
230 reviews
Singapore Airlines
8.2
Very Good
1,456 reviews
Check prices

Comfort

8.0

Overall

8.2

Food

7.8

Crew

8.6

Entertainment

8.0

Boarding

8.3

Reviews

1 / 20
10.0
Excellent

Wee Keng,Dec 2025

HKG - SIN

Quick 3 hour flight with excellent service from the crew despite it being Christmas Day holiday. Ground crew passed out Xmas cookies as well. Great experience.
British Airways
6.7
Okay
7,752 reviews
Singapore Airlines
8.2
Very Good
1,456 reviews
Check prices

Comfort

8.0

Overall

8.2

Food

7.8

Crew

8.6

Entertainment

8.0

Boarding

8.3

Reviews

1 / 20
10.0
Excellent

Wee Keng,Dec 2025

HKG - SIN

Quick 3 hour flight with excellent service from the crew despite it being Christmas Day holiday. Ground crew passed out Xmas cookies as well. Great experience.

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 17h 15m. SWISS provides one of the quickest options available for as low as £652. London and Region of 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 most popular routes from London to Region of Siem Reap?

    Most travelers choose London Heathrow - Siem Reap–Angkor Intl, London City - Siem Reap–Angkor Intl or London Gatwick - 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 £572). Flying from London to Region of Siem Reap in August is currently the most expensive (average of £879). 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

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

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 16 February 2026.
AirlineCheapestAverageFlexibilityOn-time
Austrian AirlinesCheapest£530Average£678FlexibilityNo cancel feeOn-time78%
Search Austrian Airlines flights
LufthansaCheapest£588Average£755FlexibilityNo cancel feeOn-time76%
Search Lufthansa flights
Vietnam AirlinesCheapest£607Average£717FlexibilityNo cancel feeOn-time81%
Search Vietnam Airlines flights
Singapore AirlinesCheapest£653Average£888FlexibilityNo cancel feeOn-time81%
Search Singapore Airlines flights
Thai AirwaysCheapest£845Average£899FlexibilityNo 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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