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Cheap flights from the United Kingdom to Siem Reap, Cambodia from £319

LHR — SAI
10 Oct — 17 Oct1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from United Kingdom to Siem Reap

Enter your travel dates to find the best prices.

Cheapest flights from United Kingdom to Siem Reap

Wed 16/911:15 -
2 stops23h 55m
Wed 14/1018:05 -
2 stops42h 50m
Deal found 6/9£537
Thu 3/1206:00 -
2 stops29h 30m
Mon 14/1209:55 -
2 stops35h 10m
Deal found 8/9£608
Wed 16/921:20 -
3 stops40h 50m
Wed 14/1021:10 -
2 stops27h 30m
Deal found 10/9£615
Wed 9/921:20 -
3 stops40h 50m
Wed 7/1021:10 -
2 stops27h 30m
Deal found 5/9£636
Wed 30/906:00 -
2 stops30h 55m
Wed 28/1009:55 -
2 stops29h 10m
Deal found 7/9£644
Tue 10/1107:10 -
3 stops25h 55m
Wed 18/1119:05 -
3 stops31h 25m
Deal found 10/9£650
Tue 10/1108:30 -
2 stops42h 25m
Sat 5/1216:50 -
2 stops24h 55m
Deal found 6/9£657
Wed 9/922:00 -
3 stops40h 10m
Wed 7/1021:10 -
2 stops39h 30m
Deal found 6/9£658
Wed 21/1017:30 -
2 stops34h 10m
Wed 28/1019:25 -
2 stops19h 40m
Deal found 6/9£662
Sun 25/1007:00 -
3 stops26h 05m
Fri 30/1019:05 -
3 stops33h 50m
Deal found 6/9£667
Wed 7/1006:00 -
3 stops26h 50m
Sat 10/1007:20 -
3 stops29h 35m
Deal found 9/9£669
Sat 19/919:35 -
3 stops33h 35m
Fri 2/1016:55 -
3 stops31h 40m
Deal found 10/9£687

Find flight deals from United Kingdom to Siem Reap

Round-trip from

£607

One-way from

£319

Popular in

December

Cheapest in

July

Average price

£765
Austrian Airlines
  • Austrian Airlines
  • 3/12-14/12
  • 4 total stops
  • 49h 25m total
  • United Kingdom to Siem Reap
Search Deals
3/11-31/12
  • 3/11-31/12
  • 3 total stops
  • 43h 10m total
  • United Kingdom to Siem Reap
Search Deals
Highest demand for flights based on searches. 10% potential increase in price (£67 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease (£25 potential savings vs. average return price).
Search Deals
Average for round-trip flights in September 2026
Search Deals

Cheapflights Fare Finder

 
Use the filters below to find and compare flights from the United Kingdom to Siem Reap that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest return flight

LondonSiem Reap

STN London Stansted - SAI Siem Reap–Angkor Intl

STNSAI

London Stansted

Thu 5/11

06:05-09:15

3 stops44h 10m

Siem Reap–Angkor Intl

Wed 31/12

00:00-18:00

Nonstop0h 00m

£321

LondonSiem Reap

STN London Stansted - SAI Siem Reap–Angkor Intl

STNSAI

London Stansted

Wed 4/11

17:10-09:20

3 stops33h 10m

Siem Reap–Angkor Intl

Wed 31/12

00:00-18:00

Nonstop0h 00m

£325

LondonSiem Reap

LHR London Heathrow - SAI Siem Reap–Angkor Intl

LHRSAI

London Heathrow

Mon 21/9

22:10-18:05

2 stops37h 55m

Siem Reap–Angkor Intl

Wed 31/12

00:00-18:00

Nonstop0h 00m

£327

LondonSiem Reap

LGW London Gatwick - SAI Siem Reap–Angkor Intl

LGWSAI

London Gatwick

Tue 3/11

12:15-15:00

2 stops43h 45m

Siem Reap–Angkor Intl

Wed 31/12

00:00-18:00

Nonstop0h 00m

£332

LondonSiem Reap

LTN London Luton - SAI Siem Reap–Angkor Intl

LTNSAI

London Luton

Tue 3/11

18:55-15:00

3 stops37h 05m

Siem Reap–Angkor Intl

Wed 31/12

00:00-18:00

Nonstop0h 00m

£340

LondonSiem Reap

LTN London Luton - SAI Siem Reap–Angkor Intl

LTNSAI

London Luton

Wed 4/11

05:00-15:00

3 stops27h 00m

Siem Reap–Angkor Intl

Wed 31/12

00:00-18:00

Nonstop0h 00m

£343

LondonSiem Reap

STN London Stansted - SAI Siem Reap–Angkor Intl

STNSAI

London Stansted

Fri 26/2

09:50-16:05

2 stops23h 15m

Siem Reap–Angkor Intl

Wed 31/12

00:00-18:00

Nonstop0h 00m

£343

LondonSiem Reap

LTN London Luton - SAI Siem Reap–Angkor Intl

LTNSAI

London Luton

Mon 2/11

19:05-16:05

3 stops38h 00m

Siem Reap–Angkor Intl

Wed 31/12

00:00-18:00

Nonstop0h 00m

£355

LondonSiem Reap

LHR London Heathrow - SAI Siem Reap–Angkor Intl

LHRSAI

London Heathrow

Tue 1/12

10:45-18:05

3 stops48h 20m

Siem Reap–Angkor Intl

Wed 31/12

00:00-18:00

Nonstop0h 00m

£359

LondonSiem Reap

LTN London Luton - SAI Siem Reap–Angkor Intl

LTNSAI

London Luton

Wed 9/12

06:50-19:40

3 stops29h 50m

Siem Reap–Angkor Intl

Wed 31/12

00:00-18:00

Nonstop0h 00m

£359

Flights are sorted by cheapest return flights first.

Deals found on 6/9

Showing 1-10 of 60 resultsSorted by cheapest first
1
2
3
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6

Best time to book a flight from United Kingdom to Siem Reap

Have a flexible travel schedule? Discover the best time to fly to Siem Reap from United Kingdom with our price prediction graph.
Estimated return price

Cheapflights Insights

Everything you need to know about your flight from the United Kingdom to Siem Reap

What is the cheapest month to book a flight from United Kingdom to Siem Reap?

Currently, June is the cheapest month in which you can book a flight from United Kingdom to Siem Reap (average of £651). Flying from United Kingdom to Siem Reap in December is currently the most expensive (average of £976). 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

Read through reviews of airlines operating flights from the United Kingdom 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
1,599 reviews
Check prices

Crew

8.6

Boarding

8.3

Overall

8.2

Food

7.8

Entertainment

8.1

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Walter,Aug 2026

DPS - SIN

My experience with Cathay Pacific started badly and only became more frustrating as the trip continued. It began when my original flight, which I had booked in Business Class, was canceled. Because of the cancellation, I was involuntarily downgraded. I understood that disruptions happen and was willing to accept the downgrade, but the way Cathay Pacific handled the situation afterward was extremely disappointing. The biggest issue was the lack of communication between airports. When I arrived at the next airport, the staff apparently had no record or confirmation that Cathay Pacific had downgraded me. As a result, I was forced to wait approximately an hour and a half while they tried to verify what had happened and determine how to handle my reservation. This happened at around 2:00 a.m., after an exhausting travel day that had already stretched to roughly 22 hours because of delays. At that point, I was completely exhausted and simply wanted to get to my destination and rest. Having to spend another 90 minutes resolving an issue that should have already been documented and communicated internally made an already difficult travel experience considerably worse. What was even more disappointing was the refund process. Because I had paid for Business Class but was involuntarily downgraded, I expected the fare difference to be refunded automatically. Instead, I discovered that I had to contact Cathay Pacific myself to request reimbursement. When I called, I was initially told that my situation did not qualify for a refund and that I would only be offered a travel voucher. I found that response unacceptable. I had paid for Business Class transportation that Cathay Pacific ultimately did not provide. A voucher requiring me to spend money with the airline again is not the same as refunding money for a service that was never delivered. After several heated minutes of discussion, Cathay Pacific finally agreed to refund both tickets. The cancellation itself was understandable. Even the involuntary downgrade was something I was prepared to accept given the circumstances. What made this experience unacceptable was the poor communication between airports, the lengthy middle-of-the-night delay caused by Cathay Pacific’s internal handling of the downgrade, and then having to argue simply to receive a refund for the Business Class service I had paid for but did not receive. For an airline that markets itself as a premium international carrier, I expected significantly better communication, customer service, and handling of an involuntary downgrade. Unfortunately, after this experience, Cathay Pacific has lost my confidence as a customer. This will be the last time I choose to fly with them.
Singapore Airlines
8.2
Very Good
1,599 reviews
Singapore Airlines
8.2
Very Good
1,599 reviews
Check prices

Crew

8.6

Boarding

8.3

Overall

8.2

Food

7.8

Entertainment

8.1

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Walter,Aug 2026

DPS - SIN

My experience with Cathay Pacific started badly and only became more frustrating as the trip continued. It began when my original flight, which I had booked in Business Class, was canceled. Because of the cancellation, I was involuntarily downgraded. I understood that disruptions happen and was willing to accept the downgrade, but the way Cathay Pacific handled the situation afterward was extremely disappointing. The biggest issue was the lack of communication between airports. When I arrived at the next airport, the staff apparently had no record or confirmation that Cathay Pacific had downgraded me. As a result, I was forced to wait approximately an hour and a half while they tried to verify what had happened and determine how to handle my reservation. This happened at around 2:00 a.m., after an exhausting travel day that had already stretched to roughly 22 hours because of delays. At that point, I was completely exhausted and simply wanted to get to my destination and rest. Having to spend another 90 minutes resolving an issue that should have already been documented and communicated internally made an already difficult travel experience considerably worse. What was even more disappointing was the refund process. Because I had paid for Business Class but was involuntarily downgraded, I expected the fare difference to be refunded automatically. Instead, I discovered that I had to contact Cathay Pacific myself to request reimbursement. When I called, I was initially told that my situation did not qualify for a refund and that I would only be offered a travel voucher. I found that response unacceptable. I had paid for Business Class transportation that Cathay Pacific ultimately did not provide. A voucher requiring me to spend money with the airline again is not the same as refunding money for a service that was never delivered. After several heated minutes of discussion, Cathay Pacific finally agreed to refund both tickets. The cancellation itself was understandable. Even the involuntary downgrade was something I was prepared to accept given the circumstances. What made this experience unacceptable was the poor communication between airports, the lengthy middle-of-the-night delay caused by Cathay Pacific’s internal handling of the downgrade, and then having to argue simply to receive a refund for the Business Class service I had paid for but did not receive. For an airline that markets itself as a premium international carrier, I expected significantly better communication, customer service, and handling of an involuntary downgrade. Unfortunately, after this experience, Cathay Pacific has lost my confidence as a customer. This will be the last time I choose to fly with them.
Thai Airways
7.9
Good
418 reviews
Singapore Airlines
8.2
Very Good
1,599 reviews
Check prices

Crew

8.6

Boarding

8.3

Overall

8.2

Food

7.8

Entertainment

8.1

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Walter,Aug 2026

DPS - SIN

My experience with Cathay Pacific started badly and only became more frustrating as the trip continued. It began when my original flight, which I had booked in Business Class, was canceled. Because of the cancellation, I was involuntarily downgraded. I understood that disruptions happen and was willing to accept the downgrade, but the way Cathay Pacific handled the situation afterward was extremely disappointing. The biggest issue was the lack of communication between airports. When I arrived at the next airport, the staff apparently had no record or confirmation that Cathay Pacific had downgraded me. As a result, I was forced to wait approximately an hour and a half while they tried to verify what had happened and determine how to handle my reservation. This happened at around 2:00 a.m., after an exhausting travel day that had already stretched to roughly 22 hours because of delays. At that point, I was completely exhausted and simply wanted to get to my destination and rest. Having to spend another 90 minutes resolving an issue that should have already been documented and communicated internally made an already difficult travel experience considerably worse. What was even more disappointing was the refund process. Because I had paid for Business Class but was involuntarily downgraded, I expected the fare difference to be refunded automatically. Instead, I discovered that I had to contact Cathay Pacific myself to request reimbursement. When I called, I was initially told that my situation did not qualify for a refund and that I would only be offered a travel voucher. I found that response unacceptable. I had paid for Business Class transportation that Cathay Pacific ultimately did not provide. A voucher requiring me to spend money with the airline again is not the same as refunding money for a service that was never delivered. After several heated minutes of discussion, Cathay Pacific finally agreed to refund both tickets. The cancellation itself was understandable. Even the involuntary downgrade was something I was prepared to accept given the circumstances. What made this experience unacceptable was the poor communication between airports, the lengthy middle-of-the-night delay caused by Cathay Pacific’s internal handling of the downgrade, and then having to argue simply to receive a refund for the Business Class service I had paid for but did not receive. For an airline that markets itself as a premium international carrier, I expected significantly better communication, customer service, and handling of an involuntary downgrade. Unfortunately, after this experience, Cathay Pacific has lost my confidence as a customer. This will be the last time I choose to fly with them.
Vietnam Airlines
7.7
Good
286 reviews
Singapore Airlines
8.2
Very Good
1,599 reviews
Check prices

Crew

8.6

Boarding

8.3

Overall

8.2

Food

7.8

Entertainment

8.1

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Walter,Aug 2026

DPS - SIN

My experience with Cathay Pacific started badly and only became more frustrating as the trip continued. It began when my original flight, which I had booked in Business Class, was canceled. Because of the cancellation, I was involuntarily downgraded. I understood that disruptions happen and was willing to accept the downgrade, but the way Cathay Pacific handled the situation afterward was extremely disappointing. The biggest issue was the lack of communication between airports. When I arrived at the next airport, the staff apparently had no record or confirmation that Cathay Pacific had downgraded me. As a result, I was forced to wait approximately an hour and a half while they tried to verify what had happened and determine how to handle my reservation. This happened at around 2:00 a.m., after an exhausting travel day that had already stretched to roughly 22 hours because of delays. At that point, I was completely exhausted and simply wanted to get to my destination and rest. Having to spend another 90 minutes resolving an issue that should have already been documented and communicated internally made an already difficult travel experience considerably worse. What was even more disappointing was the refund process. Because I had paid for Business Class but was involuntarily downgraded, I expected the fare difference to be refunded automatically. Instead, I discovered that I had to contact Cathay Pacific myself to request reimbursement. When I called, I was initially told that my situation did not qualify for a refund and that I would only be offered a travel voucher. I found that response unacceptable. I had paid for Business Class transportation that Cathay Pacific ultimately did not provide. A voucher requiring me to spend money with the airline again is not the same as refunding money for a service that was never delivered. After several heated minutes of discussion, Cathay Pacific finally agreed to refund both tickets. The cancellation itself was understandable. Even the involuntary downgrade was something I was prepared to accept given the circumstances. What made this experience unacceptable was the poor communication between airports, the lengthy middle-of-the-night delay caused by Cathay Pacific’s internal handling of the downgrade, and then having to argue simply to receive a refund for the Business Class service I had paid for but did not receive. For an airline that markets itself as a premium international carrier, I expected significantly better communication, customer service, and handling of an involuntary downgrade. Unfortunately, after this experience, Cathay Pacific has lost my confidence as a customer. This will be the last time I choose to fly with them.
Austrian Airlines
7.6
Good
958 reviews
Singapore Airlines
8.2
Very Good
1,599 reviews
Check prices

Crew

8.6

Boarding

8.3

Overall

8.2

Food

7.8

Entertainment

8.1

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Walter,Aug 2026

DPS - SIN

My experience with Cathay Pacific started badly and only became more frustrating as the trip continued. It began when my original flight, which I had booked in Business Class, was canceled. Because of the cancellation, I was involuntarily downgraded. I understood that disruptions happen and was willing to accept the downgrade, but the way Cathay Pacific handled the situation afterward was extremely disappointing. The biggest issue was the lack of communication between airports. When I arrived at the next airport, the staff apparently had no record or confirmation that Cathay Pacific had downgraded me. As a result, I was forced to wait approximately an hour and a half while they tried to verify what had happened and determine how to handle my reservation. This happened at around 2:00 a.m., after an exhausting travel day that had already stretched to roughly 22 hours because of delays. At that point, I was completely exhausted and simply wanted to get to my destination and rest. Having to spend another 90 minutes resolving an issue that should have already been documented and communicated internally made an already difficult travel experience considerably worse. What was even more disappointing was the refund process. Because I had paid for Business Class but was involuntarily downgraded, I expected the fare difference to be refunded automatically. Instead, I discovered that I had to contact Cathay Pacific myself to request reimbursement. When I called, I was initially told that my situation did not qualify for a refund and that I would only be offered a travel voucher. I found that response unacceptable. I had paid for Business Class transportation that Cathay Pacific ultimately did not provide. A voucher requiring me to spend money with the airline again is not the same as refunding money for a service that was never delivered. After several heated minutes of discussion, Cathay Pacific finally agreed to refund both tickets. The cancellation itself was understandable. Even the involuntary downgrade was something I was prepared to accept given the circumstances. What made this experience unacceptable was the poor communication between airports, the lengthy middle-of-the-night delay caused by Cathay Pacific’s internal handling of the downgrade, and then having to argue simply to receive a refund for the Business Class service I had paid for but did not receive. For an airline that markets itself as a premium international carrier, I expected significantly better communication, customer service, and handling of an involuntary downgrade. Unfortunately, after this experience, Cathay Pacific has lost my confidence as a customer. This will be the last time I choose to fly with them.
British Airways
6.7
Okay
8,210 reviews
Singapore Airlines
8.2
Very Good
1,599 reviews
Check prices

Crew

8.6

Boarding

8.3

Overall

8.2

Food

7.8

Entertainment

8.1

Comfort

8.0

Reviews

1 / 20
2.0
Mediocre

Walter,Aug 2026

DPS - SIN

My experience with Cathay Pacific started badly and only became more frustrating as the trip continued. It began when my original flight, which I had booked in Business Class, was canceled. Because of the cancellation, I was involuntarily downgraded. I understood that disruptions happen and was willing to accept the downgrade, but the way Cathay Pacific handled the situation afterward was extremely disappointing. The biggest issue was the lack of communication between airports. When I arrived at the next airport, the staff apparently had no record or confirmation that Cathay Pacific had downgraded me. As a result, I was forced to wait approximately an hour and a half while they tried to verify what had happened and determine how to handle my reservation. This happened at around 2:00 a.m., after an exhausting travel day that had already stretched to roughly 22 hours because of delays. At that point, I was completely exhausted and simply wanted to get to my destination and rest. Having to spend another 90 minutes resolving an issue that should have already been documented and communicated internally made an already difficult travel experience considerably worse. What was even more disappointing was the refund process. Because I had paid for Business Class but was involuntarily downgraded, I expected the fare difference to be refunded automatically. Instead, I discovered that I had to contact Cathay Pacific myself to request reimbursement. When I called, I was initially told that my situation did not qualify for a refund and that I would only be offered a travel voucher. I found that response unacceptable. I had paid for Business Class transportation that Cathay Pacific ultimately did not provide. A voucher requiring me to spend money with the airline again is not the same as refunding money for a service that was never delivered. After several heated minutes of discussion, Cathay Pacific finally agreed to refund both tickets. The cancellation itself was understandable. Even the involuntary downgrade was something I was prepared to accept given the circumstances. What made this experience unacceptable was the poor communication between airports, the lengthy middle-of-the-night delay caused by Cathay Pacific’s internal handling of the downgrade, and then having to argue simply to receive a refund for the Business Class service I had paid for but did not receive. For an airline that markets itself as a premium international carrier, I expected significantly better communication, customer service, and handling of an involuntary downgrade. Unfortunately, after this experience, Cathay Pacific has lost my confidence as a customer. This will be the last time I choose to fly with them.

Related info for your journey

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

    Siem Reap–Angkor Intl (SAI) is the airport you will fly into if you book a flight from United Kingdom to Siem Reap. It is only a 24.7 mi journey from Siem Reap–Angkor Intl (SAI) to Siem Reap’s city center.

  • How long is the flight from United Kingdom to Siem Reap?

    A quick flight from United Kingdom to Siem Reap can take about 19h. China Eastern provides one of the quickest options available for as low as £714. United Kingdom and Siem Reap are separated by a distance of 6132 mi. Both multi-stop and direct flights can be found to your destination and back.

  • What are the cheapest airlines to fly from United Kingdom to Siem Reap one-way?

    One-way options have recently been found by users for as low as £165 on Singapore Airlines. Other airlines that offer cheap prices include Austrian Airlines from £375 and Vietnam Airlines from £417 one-way.

  • What are the most popular routes from United Kingdom to 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 United Kingdom to Siem Reap.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from United Kingdom 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 United Kingdom to Siem Reap?

    Currently, June is the cheapest month in which you can book a flight from United Kingdom to Siem Reap (average of £651). Flying from United Kingdom to Siem Reap in December is currently the most expensive (average of £976). 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

Top 5 airlines flying from United Kingdom to Siem Reap

AirlineCheapestAverageFlexibilityOn-time
Austrian AirlinesCheapest£535Average£682FlexibilityNo cancel feeOn-time78%
Search Austrian Airlines flights
Etihad AirwaysCheapest£542Average£661FlexibilityNo cancel feeOn-time75%
Search Etihad Airways flights
Vietnam AirlinesCheapest£611Average£808FlexibilityNo cancel feeOn-time81%
Search Vietnam Airlines flights
Singapore AirlinesCheapest£658Average£934FlexibilityNo cancel feeOn-time81%
Search Singapore Airlines flights
Thai AirwaysCheapest£882Average£1,013FlexibilityNo cancel feeOn-time77%
Search Thai Airways flights

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