LHR - SAI

Find cheap flights from London to Siem Reap

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KAYAK searches hundreds of travel sites at once for deals on flights to Siem Reap

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from London to Siem Reap, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from London to Siem Reap, as well as popular online travel agencies
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Cheap Flight Deals 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.

Recent return flight deals from London to Siem Reap

KAYAK's recommended return flight deals from the most popular airlines that fly from London to Siem Reap.
Discover the best prices for you by selecting your travel dates on KAYAK.
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Multiple Airlines Logo
LHR-SAI
6106 mimulti-stop
Multiple Airlines Logo
SAI-LHR
6106 mimulti-stop
Multiple Airlines
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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 May, where tickets cost £668 (return) on average. On the other hand, the most expensive months are August and December, where the average cost of round-trip tickets is £1,361 and £1,333 respectively.

How far in advance should I book a flight from London Heathrow Airport to Siem Reap?

To calculate weekly average prices, KAYAK takes all prices for each week before departure 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 average of all the values for each week.
To get a below average price on the flight from London Heathrow Airport to Siem Reap, you should book around 2 weeks before departure. For the absolute cheapest price, our data suggests you should book 5 weeks before departure.

Good to know - Cheap tickets from London to Siem Reap

Low season

September

High season

January
Best time to beat the crowds (22% less expensive on average)
Most popular time to fly and prices are also 6% lower on average.

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

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

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

  • 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.

See more FAQs

Top 3 airlines serving 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.
8.1
Singapore AirlinesOverall score based on 1290 reviews
7.9Comfort
7.7Food
8.2Boarding
8.6Crew
8.0Entertainment
Airline reviews

Very good flight from Boarding to landing -efficient and comfortable with decent entertainment options

10.0 ExcellentAnonymous, Mar 2025LAX - NRT
Read more Singapore Airlines reviews

Very good flight from Boarding to landing -efficient and comfortable with decent entertainment options

Excelent service and plenty of food and drinks during the flight. Flight crew very attentive to our needs. Leg room between rows are very disappointing.

The seat in economy class and legroom in Singapore airline are narrower than Korean airlines! I don’t have that comforting feeling flying with Singapore air as in the past!

Loved the airline with the exception of their carry on limitations. They enforce a strict 7 kilo limit for carry on baggage which is ridiculous. We traveled from SFO to SIN with carry on with no difficulty yet when we checked in Delhi they forced us to check the carry on bags. The weight of our carry on bags were 11 and 12 kilos and while they exceeded the limitations set by Singapore Airlines they were well under weight limitations set by may other carriers. Interestingly my wife and I were each allowed two 22 KG bags to check in addition to the 7 kg carry on for a total weight of 102 KG's. Our total weight with the one bag we planned to check and our two carry ons was 46 kgs.

Crew and service was excellent, but passengers should be offered a welcome drink before take off which did not happen. Food was very good. Unfortunately the lie-flat bed in business class was one of the most uncomfortable I have experienced. The configuration forces you to sleep with your legs at an angle instead of in a straight line, plus there is very little padding on the bed so it wasn't possible to sleep for more than 2-3 hours on an 18 hour flight. For what the airlines charges for a business class ticket their hard product leaves a lot to be desired.

So happy I flew with Singapore Airlines. The customer service is top notch. I am terrified of flying and the staff made me feel so at ease. Will only fly Singapore internationally moving forward.

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

It was an average flight. I would have expected more from this airline. Food, seats, service, etc was just average. I just give them some extra points for offering free WiFi on board with just a Krisflyer account.

Check in was easy through self-check-in kiosks just like domestic flights. Staff onboard were fantastic. Some "book the cook" good options weren't great, others really good. Entertainment options a bit limited to what I've experienced on Qantas. Overall a good flight though, especially for the price.

The food options and quality could use some more excitement and variety.

They used Thai Smile plane, which is a smaller model and used to service only domestic flights; hence, the plane is small and quite compact. No entertainment on the flight. While boarding was delayed, it was done in a quick manner.

I give EVA 5 stars in every category. I enjoy this airline and it's great team of employees. I always highly recommend EVA to friends and family and everyone.

The flight was delayed going out of the gate at BKK that made it a difficult challenge to get through immigration transfer at tapei and make it to my departure on time. This appears to be a recurring issue. The flight crew and cabin crew were excellent. The food was very nice.

The boarding efficiency was good. A couple of the flight attendants did not seem in the best of moods. Overall it was a good experience.

The setting configuration of the aircraft stinks. Nobody should pay business class fares and be so uncomfortable. The design of facing fellow passengers is a brilliant nincompoop.

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.

Delayed flight in Singapore caused the transfer at Bangkok to be very stressful. Fortunately, no elderly were in this trip, else it will not be possible to catch the connecting flight. There were also several occasions throughout the flight journey where some of the passengers were not wearing their seat belts despite several remainders from the stewardess.

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??

Always liked Thai Airways but in the past they have been very expensive, not being a millionaire just yet, I will use cheaper airlines. Bangkok to London £370 11 hours 45 mins. Old plane but ok. Lovely ladies on board, very polite. Food was ok. Will always use them if the price is right.

I bought the front row seat and made and early online check in but they changed my seat to the back row without prior notice. The inflight meal was too poor, only a piece of small finger food. The boarding is a disaster, everyone is stuffed in a bus in chaos. Doesnt worth the money at all.

Poor. Flight was delay without prior notice. Poor boarding. Poor meal service. Plane was dirty and smelly. Does not worth the money.

Overall very nice airline. The seats were cloth unlike leather seats I am accustom to on planes. The food was adequate. I had to use a paper boarding pass as they do not like electronic boarding passes. I scanned my electronic pass, but the gate agent requested the paper pass. Luckily I had a paper pass, although my electronic pass worked and when the paper pass was scanned it stated I was already on board.

Overall very nice airline. The seats were cloth unlike leather seats I am accustom to on planes. The food was adequate.

I am a bit upset with the check in counter, I signed up a wheelchair for my mom so they wouldn’t grant us her boarding pass. We got to the airport a couple of hours earlier and they had us wait and no one ever gave us her boarding pass or the wheelchair, I had to go back and complain when it was already time for our flight to board. Since we got their earlier, I could have easily pushed my mom myself and we could have relaxed and went to the lounge while waiting… when I finally got someone to help us he couldn’t explain how and why they dismissed us in the first place.

Was on holiday with my partner and we booked with Vietnam airlines as it not meant to be a budget airline. They separated us and made us sit at either end of the plane. Not the way I planned to spend my time on my holiday separate from my loved one. How can they separate people on the same booking. They know we are together and spending quality time together.

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

The check-in process was great, and I cannot remember the name of the supervisor, but he was good and told us about the transit process very correctly and efficiently and kindly. We were given down access and the overall process was very efficient.

The plane had a technical problem it would delayed 10 hours but they just gave limited information and put all passengers into the Miracle lounge. Ther were not enough chairs and so on.

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

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

Information on your arrival and departure airports

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