Find Cheap Flights from London to Siem Reap

1 adult
1 adult, Economy, 0 bags

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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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 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 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 to Siem Reap is September, when tickets cost £700 (return) on average. On the other hand, the most expensive months are December and April, when the average cost of return tickets is £1,287 and £1,112 respectively.

How far in advance should I book a flight from London 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 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 to Siem Reap, you should book around 1 week before departure. For the absolute cheapest price, our data suggests you should book 9 weeks before departure.

Good to know - Cheap tickets from London to Siem Reap

Low seasonJuly
Best time to beat the crowds but there is an average 23% increase in price.
Most popular time to fly and prices are also 18% lower on average.

FAQs - booking Siem Reap flights

  • 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 from London to Siem Reap 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 from London to Siem Reap with an airline and back 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 from London to Siem Reap up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

  • What is the cheapest time of day to fly to Siem Reap?

    The cheapest time of day to fly to Siem Reap is generally at night, when retur flights cost £763 on average. Morning departures are around 9% cheaper than evening flights, on average. The most expensive time of day to fly to Siem Reap is generally in the evening, which is peak travel time and where the average cost of a ticket is £921.

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.
8.1
Singapore AirlinesOverall score based on 1389 reviews
8.0Comfort
8.0Entertainment
8.3Boarding
8.6Crew
7.7Food
Airline reviews

I was in a middle seat where I felt a bit too cramped otherwise the trip was good

8.0 ExcellentAnonymous, Sept 2025SIN - BLR
Read more Singapore Airlines reviews

I was in a middle seat where I felt a bit too cramped otherwise the trip was good

Crew and service excellent. 2 hour delay for takeoff. SQ app showed flight on time.

Food from Surabaya was below average but from Singapore is much better

The usual excellent experience with Singapore Airlines. The airplane was on time and actually early to Haneda Airport. The onboarding experience was pleasant with no delays, perhaps owing to the fact that the flight was not full. Nevertheless, the air crew were their usual outstanding standards in serving the passengers.

Construction at PDX resulting in very lung walk from the rental car to the gate. SFO, extremely long walk between terminals to get to connecting Singapore airlines flight. My smart watch recorded a total of 3 miles.

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!

I very much liked and appreciated the service on board. The seating arrangement in Business feels uncomfortable. It's not made for tall people, in any case.

Great airline. Excellent service, good food & lots of TV movies/shows to choose from.

Crews were very caring and polite. Washroom was surprisingly clean. Overall experience was good , only food choices was very limited. Thanks

On time boarding I would like to see ground hostess to help transit customers to direct them to the right terminal and boarding gate. Last night, all the transit customers on SQ484 arriving Singapore had to merry go round to look for terminal and boarding gate to board SQ128 transit to KL Malaysia. We went to Terminal 3 taking the Skytrain to T3 and back to T3 to get out to look for different Skytrain to T2. On arrival t2, we had to go round to ask which boarding gate to KL. We only had 5 minutes to make to the boarding time at 6:55pm but we already spent more than 30 minutes running around to find the boarding gate. We were late at the boarding gate.

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.

Need to improve on punctuality. My flight was delayed by 1 hour.

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

Except that our flight was cancelled, by mail, and later moved to 12 hours prior, then the experience was good. In Bangkok we were offered a hotel, it was fine, but would have been nice to know in advance😉

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).

Although booked meal of fruit only The crew had not received this special meal The same happened on my flight Bangkok / CAN The films are so old that best is to use own computer to watch downloads . Serve nuts but they do not warm up . Service is attentive , WC clean

Terrible. It’s like they are stuck in the dark ages. I brought a standard carry on suitcase and a back pack - I was told I could only carry on 7kg per bag - in business class, I was forced to remove articles from the suitcase and put them into my backpack! That’s the most ridiculous thing I’ve ever encountered in all my years of flying. The two bags weighed the same amount but one could not be more than 7kg. Holy cow.

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.

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

For a domestic flight, seats are ok, but fir us as tall dutchies, the legroom is too small. However, for a short and affordable flight, is not a big problem. Staff is still very nice and a complementary water very welcome.

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

Average, not more then that. Cannot compete with Singapore Airlines

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.

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 😊

We always use BA due to the direct flight options, we have always had a pleasant flight with BA.

There might be more food options for people who can't eat so much starch/sugar/bread/rice. Meat, cheese, walnuts/pecans for snack, maybe jerky or other kinds of meat-based snacks would be better than bread and rice and sweets. I had an extra chardonnay, which was fine. The entertainment was great.

Unfortunately, my flight was cancelled because of some sort of emergency over the Atlantic and had to return to London. While I think British Airways made every effort to mitigate the situation, I must say it was still pretty unpleasant. I do appreciate the fact, however, that British Airways put my safety first…and I think the effort to correct a bad situation was very sincere. But I think the process might be handled better in future.

Horrible leg room - coach seating with empty seat in middle on a 3 across seating. You buy business class for comfort which includes leg room. Absolutely no entertainment options either. Awful experience

Flight was 3h50 and was only provided with a packet of oat cookies and offered a cold drink. Thankfully i'd had breakfast but for a morning flight of that length some sort of breakfast should be included. There were 2 toilets for economy but due to turbulence we couldn't use them until the last 1hr which meant the queue was then huge. Would've been nice to open up the business one for those closest to the front to use.

Crew service was poor and very little difference between premium economy and economy. Disappointed.

My bags never made it on the flight and I now have to wait for them to arrive hopefully tomorrow. You can’t even track your bags in the app to see where they are since they didn’t arrive. You have to file a claim and then wait for them to inform you when you will receive your bag. We were already delayed for an hour due to baggage so I don’t understand how my bag didn’t make the flight.

One of the worst experience given the middle seat even asked for the change no one honored,boarded at the end and overall one of the worst experience

No WiFi in either flight. No leg room, the seat in front of me left dents on my knees and the tray was so low my knees propped it up if I tried to use it.

It was good although our flight to the UK was cancelled and rescheduled for two days later. This was after we were already seated on the plane. We missed the first leg of our trip. BA did put us up at a hotel and paid for our meals but we lost our hotel costs in Glasgow.

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

Cabin class types available on flights to Siem Reap

Cabin classes available on flights to Siem Reap. Prices are the lowest found on KAYAK over the last 7 days. Price and availability is not guaranteed.

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