Find cheap flights from London to Siem Reap

1 adult
1 adult, Economy

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
Travellers love KAYAK
41,299,237 searches in the past 7 days on KAYAK

Save 27% or moreCompare multiple travel sites with one search.

Track pricesNot ready to book? Create a price alert for when prices drop.

Bundle and saveSave money when you bundle your flight + hotel.

Filter your dealsChoose cabin class, free Wi-Fi and more.

Flights Deals
Useful Info
Flights Deals
Useful Info

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 £679 (return) on average. On the other hand, the most expensive months are December and August, when the average cost of return tickets is £1,346 and £1,244 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 5 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 seasonAugust
High seasonJanuary
Best time to beat the crowds but there is an average 39% increase in price.
Most popular time to fly and prices are also 20% 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 £1,006 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 £1,214.

Top 4 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 1302 reviews
7.7Food
7.9Comfort
8.0Entertainment
8.2Boarding
8.6Crew
Airline reviews

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.

10.0 ExcellentPierre, Mar 2025PDX - SFO
Read more Singapore Airlines reviews

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.

Timing very good from sfo to Singapore and service was awesome and economy class seats are great overall very good experience thanks

The crew and their service was top notch, but the plane itself seemed to be on the older side and worn out. Also, the food could’ve been better. 9 out of 10.

Service excellent would chose Singapore airlines as my first choice

The staff were amazing and very kind. The seats recline a little too far back and are up close when sitting behind.

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.

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.

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.

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.

I didn’t have food and they don’t include entertainment. Not much leg room at all. Staff were great.

Better synchronizing the boarding processes. The audio announcements, the personnel and the digital signage were not saying the same thing. All confusion.

Business class was nothing more than Economy with middle seat empty. Uncomfortable seat and leg room. A mom behind me had a 18 month/2 yr old on her lap, who had his feet on my back all the time- while middle seat remained empty. Pretty much not worth the fare. Very disappointed.

The first class seats were unusable, mine at the end of the flight, my husband's in the middle of the flight, and the one next to me was unusable either, they had to move the person to another seat.

charging port did not work, no entertainment system. Other than that the flight was good and safe.

Last minute gate change. Didn’t put our TSA global on our trip even though we asked multiple times to confirm. Did not help with food when could not eat what was served.

When Stephen arrived with our wheel chairs - we were in excellent hands! He was such great help with getting our rental car and then reporting our missing luggage. When you are exhausted from traveling for too many hours, he was just what we needed to navigate everything! Give that guy a raise!

The cabin was bit colder than I like but the crew members looked after us very well. They did even offer hot water bottle and hot chocolate. I cannot rate the crew enough excellent is not good enough. They really were wonderful.

Boarding is always a challenge as folks in al groups crowd around for no reason, but crew handled it well. I once again applaud the LHR ground baggage staff as they got our bags from a flight at Terminal 5A to a flight in Terminal 5C within 40 minutes...amazing!

Gate information deliberately delayed to only one hour B4 flight, lack of info finding gate.

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.

Not what you’re looking for? Find thousands of other hotels, flights, car hires and package deals with KAYAK.