LHR - SAI

£364 Find Cheap Flights from London to Siem Reap – Compare and Save

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from London to Siem Reap departing on 8/7. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

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Everything you should know

Cheapest return fare
£599
Typical prices: £654-£917
SWISS
Sat 31/10Mon 9/11
LHR - SAI • 2 stops
Cheapest one-way flight
£364
Typical prices: £401-£840
Etihad Airways
Wed 8/7
LHR - SAI • 2 stops
Top airlines
Cheapest • from £599 (return)
Best reviews • 8.2 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
Direct flights
Not available
There are currently no direct flights between London and Siem Reap. You’ll need at least 1 connection.
Insights
Insights
Insights
Insights
Top stopover airports
Cheapest • Avg £746 (return)
Shortest trip • 13h 55m (one-way)
Insights
Insights
Insights
Insights
When to travel
Cheapest • 100% price drop
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
Start a new search
KAYAK searches hundreds of sites at once to find you the best travel deals.
We hope you love your trip to Siem Reap!
Flight Deals
Booking Insights
Flight Deals

Cheap Flights from London to Siem Reap (LHR-SAI)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for return flights from London to Siem Reap that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent return flight deals from London to Siem Reap

Sat, 31 Oct - Mon, 9 Nov
SWISS Logo
18:40 - 09:50
LHR
-
SAI
32h 10m
2 stops
SWISS Logo
09:55 - 21:40
SAI
-
LHR
18h 45m
2 stops
£599SWISS
Wed, 30 Sep - Mon, 5 Oct
SWISS Logo
18:40 - 09:40
LHR
-
SAI
33h 00m
2 stops
SWISS Logo
09:40 - 21:45
SAI
-
LHR
18h 05m
2 stops
£599SWISS
Sat, 31 Oct - Sat, 7 Nov
SWISS Logo
18:40 - 09:50
LHR
-
SAI
32h 10m
2 stops
SWISS Logo
16:45 - 11:15
SAI
-
LHR
25h 30m
2 stops
£606SWISS
Fri, 30 Oct - Sun, 8 Nov
SWISS Logo
18:40 - 09:50
LHR
-
SAI
32h 10m
2 stops
SWISS Logo
09:55 - 21:40
SAI
-
LHR
18h 45m
2 stops
£614SWISS
Thu, 29 Oct - Mon, 9 Nov
SWISS Logo
13:45 - 18:45
LHR
-
SAI
22h 00m
2 stops
SWISS Logo
09:55 - 11:15
SAI
-
LHR
32h 20m
2 stops
£631SWISS
Thu, 29 Oct - Sat, 7 Nov
SWISS Logo
06:00 - 18:45
LHR
-
SAI
29h 45m
2 stops
SWISS Logo
16:45 - 08:05
SAI
-
LHR
22h 20m
2 stops
£638SWISS
Thu, 29 Oct - Sun, 8 Nov
SWISS Logo
09:00 - 18:45
LHR
-
SAI
26h 45m
2 stops
SWISS Logo
09:55 - 21:40
SAI
-
LHR
18h 45m
2 stops
£646SWISS
Fri, 25 Sep - Fri, 9 Oct
Multiple Airlines Logo
15:20 - 09:00
LHR
-
SAI
35h 40m
3 stops
Multiple Airlines Logo
19:20 - 21:25
SAI
-
LHR
32h 05m
3 stops
£672Multiple Airlines
Wed, 19 Aug - Wed, 16 Sep
Multiple Airlines Logo
06:00 - 18:55
LHR
-
SAI
30h 55m
2 stops
Multiple Airlines Logo
09:40 - 21:45
SAI
-
LHR
18h 05m
2 stops
£677Multiple Airlines
Sat, 7 Nov - Sat, 21 Nov
SWISS Logo
18:40 - 09:50
LHR
-
SAI
32h 10m
2 stops
SWISS Logo
09:55 - 08:05
SAI
-
LHR
29h 10m
2 stops
£678SWISS
Booking Insights

KAYAK’s insights & trends for London to Siem Reap flights

Get data-powered insights and trends into flights from London to Siem Reap to help you find the cheapest flights, the best time to fly and much more.

What is the cheapest month to fly from London Heathrow Airport to Siem Reap?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from London Heathrow Airport to Siem Reap, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from London Heathrow Airport to Siem Reap is August, where tickets cost £0 (return) on average. On the other hand, the most expensive months are July and February, where the average cost of round-trip tickets is £918 and £916 respectively.

Good to know - Cheap tickets from London to Siem Reap

Low seasonMarch
Cheapest flight£364
Best time to beat the crowds (16% less expensive on average)
Most popular time to fly (1% more expensive on average)
Flight from London to Siem Reap

When to book flights from London to Siem Reap

Are your dates flexible? Find out the best times to travel from London to Siem Reap based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated return price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or returns with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking London to Siem Reap flights

  • What is the cheapest flight from London Heathrow Airport to Siem Reap?

    In the last 3 days, the lowest price for a flight from London Heathrow Airport to Siem Reap was £364 for a one-way ticket and £599 for a return.

  • Which airports will I be using when flying from London to Siem Reap?

    London and Siem Reap are both served by 1 main airport. You will leave London from London Heathrow and will be arriving at Siem Reap–Angkor Intl.

  • Which aircraft models fly most regularly from London to Siem Reap?

    We unfortunately don’t have that data for this specific route.

  • Which airline alliances offer flights from London to Siem Reap?

    SkyTeam, and Star Alliance are the airline alliances operating flights between London and Siem Reap, with SkyTeam being the most commonly used for this route.

  • Which is the best airline for flights from London to Siem Reap, Singapore Airlines or Thai Airways?

    The two airlines most popular with KAYAK users for flights from London to Siem Reap are Singapore Airlines and Thai Airways. With an average price for the route of £785 and an overall rating of 8.2, Singapore Airlines is the most popular choice. Thai Airways is also a great choice for the route, with an average price of £964 and an overall rating of 7.9.

  • How does KAYAK find such low prices on flights from London to Siem Reap?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from London to Siem Reap.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from London to Siem Reap?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Siem Reap from London is likely to change within 7 days, so travellers know whether to wait or book now.

  • What is the Hacker Fare option on flights from London to Siem Reap?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional return ticket. You could then fly to Siem Reap with an airline and back to London with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from London to Siem Reap?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Siem Reap from London up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Reviews of the top 4 airlines flying from London to Siem Reap

 
See real verified KAYAK customer reviews for airlines flying from London to Siem Reap. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from London to Siem Reap? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.2
Singapore AirlinesOverall score based on 1557 reviews
8.0Comfort
7.8Food
8.3Boarding
8.6Crew
8.1Entertainment
Airline reviews

Food was terrible , uncomfortable seats, WiFi did not work, will never fly Singapore again.

2.0 MediocreAnonymous, May 2026
LAX - NRT
Read more Singapore Airlines reviews

Food was terrible , uncomfortable seats, WiFi did not work, will never fly Singapore again.

Really great service throughout and the food was really nice. I can highly recommend thank you very much.

Everything was great keep up the good work 😁, can't ask for more.

Service excellent would chose Singapore airlines as my first choice

I was traveling with my 3 minor children, one leg I was seated two aisles behind them. On the longest leg I would have preferred sitting across the aisle from them, not behind. My youngest is 4yos. I understand airplane seating configurations are not the airlines problem but seating the one adult with a reservation apart from the minors was very difficult.

Crews are not allowed to perform any service whenever the captain deems there’s a chance of turbulence. Even if it is perfectly smooth air.

Perfect experience from boarding through to leaving the flight, comfortable and personalised service from all staff, highly recommended

The male traveller seated in the row in front diagonally opposite my husbands seat across the aisle as soon as the seatbelt sign went off moved across the aisle into the seat in front of my husband for the entire journey from London to Singapore he had his seat reclined and pushed back and the seat touching my husbands knees for the entire journey from London to Singapore. very uncomfortable for my husband.

Crew is phenomenal. Helpful with anything you may need. Lots of entertainment options. Food was good. On time, no complaints.

More Baggage limit Alternative of virtual check in at airport , prefer personal touch with “real person”check in counter for baggage drop

The flight (boarding) was delayed by 40-50 minutes and there was very crowed. They need to improve on the timeliness & boarding process. (They asked passenger to board in groups, but the 2nd group was standing there waiting for 20 minutes!). However, services from the crew was very good, also the food was good as well. I also found the legroom was quite comfortable.

Seats were uncomfortable and the vegetarian meal was awful. Some of the entertainment didn't work.

The flight was mostly fine, but I really wished that seats had an outlet to charge devices considering the length of the flight (15 hours there and 14 hours back).

Entertainment is limited with a relatively old catalogue. Wi-Fi never works and the cabin and lavatory had evidence of a lot of scuff marks and temporary repairs. Nothing unsafe, but a bit tatty in places.

USB charging port was not working at my seat 48K.

I enjoy flying with Thai Airways, however their B788 business class configuration is quite dated. Additionally , while the service is always friendly and efficient, I’m getting tired of the same “usual suspects” when it comes to food choices. Since it was a lunchtime flight, what about some gourmet sandwiches or some type of salad dish for the main course? The entertainment options are also quite limited and this is not unique to TG, so much so that given the short duration of the flight I ended up not bothering with any entertainment. Finally, despite signs around the cabin advising wifi available, I was unable to con-net and in fact I’ve never been able to connect on any TG flight over the last year or so - what’s the go here??

The flight attendants ignored us several times which was annoying. The sandwich thing wasn't very good but it's only an hour flight, it would have been better to have entertainment over bad food.

Check in was a disaster. 90 minutes and only 2 economy check in desks open. Had to rush to catch the flight.

I couldnt go on this flight and lost all my money over 1,000 UK Pounds as my visa to Myanmar was not accepted :(

After going back and forth with the airline, they never reimbursed the airline tickets. Went around asking multiple people how to get reimbursed and kept getting put back, not satisfied with their customer service.

The aircraft was little tired but the food and service was outstanding

This was our fourth domestic flight with Vietnam Airlines, and once again we found the experience very suitable. Check-in was easy and efficient. They did take our carry-on luggage, but that was fine. I’m actually happy not to deal with it on such a short flight. The flight was just over an hour, departed on time, and we climbed above the clouds into a beautiful sunset. Even on such a short flight, they served water, which we appreciated. Luggage came out into carousel in Nha Trang in good time and off we went to meet our GRAB. Also, Vietnam Airlines have easy to locate ground level offices in cities and towns where you can get assistance with staff. I liked this service as we did go visit one in Nha Trang. We would definitely recommend Vietnam Airlines and wouldn’t hesitate to fly with them again.

Really good 👍 This was our first time flying with Vietnam Airlines. It was a short domestic flight, so no meal service, but boarding was organized and the flight departed and arrived on schedule. The flight attendants were professional and neatly presented. All in all, a very good first experience. We would recommend Vietnam Airlines.

Very good flight and very kind crew Only thing is I wish there would be a vegetarian option for the meals

Lovely staff, comfortable seats. Transit time was short but they had great processes in place to get us on the plane.

2 hours delay, time changes started already 2 days before the flight

I had sometimes my trips with Vietnam Airlines and I like it 😊

Ensure there is a choice of food for all customers and also enough food

An excellent airline; polite and courteous cabin crew, excellent meal and drink service. Highly recommended.

Technical problems checking in. Had to wait a long time while they got things ready.

OK, would prefer some meat for dinner, not just pasta although was tasty. There was only one dish, no choices

Short flight. Bare bones and kinda seeming like an older plane. But got me there on time and that's what counts. Perfectly fine flight all the way from start to finish.

My layover in Vienna was supposed to be 35 minutes but because my flight was canceled I had to wait in the airport for an additional 8 hours.

We had a wonderful experience overall. The only issue was check-in our luggage at the Split Airport counter. It was very confusing because we needed to pay for baggage.

We have travelled on 13 December with Austrian Airlines from Yangon through Bangkok and Vienna to Varna. The first flight operated by Thai Airlines was nice and comfortable. I wouldn’t say the same thing about the next two flights which were operated directly by the Austrian Airlines. During our flight from Bangkok to Vienna:  > The service was very poor – serving of food and drinks was disorganized, late and not combined, the stewards were walking back and forth without doing anything substantial for the passengers. Even the morning breakfast was very late with a cup of coffee almost while landing (after a reminding).  > The food itself was OK-ish but for a 12-hour flight, there were no snacks/bites in between dinner and breakfast as it is with the other airlines.  > The cutlery was wooden, most probably recycling, but very unpleasant to eat with.  > The stewards were not rude but not friendly and/or helpful  > And also, half of the passengers had travel sets, others did not. The flight from Vienna to Varna was another surprise: firstly, the flight was late and secondly, they were serving only water free, even the coffee was paid, so were the snacks, but we had to pay to reserve seats. The whole experience is as if it was a low-cost airline. All in all, I wouldn’t recommend using the services of Austrian Airlines: the ticket prizes are quite the same as of the other carriers flying to this destination and you would have much pleasant time.

It was very good, ,especially the working people in the plane, they are so polite.,thank you

From all the segments I flew it was the only one I did not get the option to choose ni seat, I did not get the quality of seat I had paid for. Crew was nice, airplane was clean, but no food, only water and a small courtesy chocolate. Everything else you had to pay for.

Premium Economy is good value in comparison to Business Class. Not all the perks of Business but a lot of leg room and wider seat and elbow room. Food was very good. I even asked for a Gruner Veltliner wine which was not on the trolley and the attendant went into Business/First to get me a glass. Nice little touch. I would like to have a wider selection of music -- more 70's-80's (guess how old I am).

There were a number of passengers scheduled to transfer to the flight from Vienna to Warsaw. None of them made it because the crew failed to assist them in getting to the gate for the Warsaw bound flight in time. It could have been done very easily with proper assistance.

I flew business class. But nothing compare to business class. Lounge closed in Vienna. Not exist at all in Tel Aviv. Priority boarding not exist in Tel Aviv despite available business counter. Nobody in front of me was checked in to Business or with Senator status. No welcome drinks. All overall awful experience.

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

Information on your arrival and departure airports