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 £689 (return) on average. On the other hand, the most expensive months are December and April, when the average cost of return tickets is £1,298 and £1,095 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 12 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 £752 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 £908.

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 1413 reviews
8.3Boarding
7.8Food
8.0Entertainment
8.6Crew
8.0Comfort
Airline reviews

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

8.0 ExcellentAnonymous, Sept 2025
SIN - 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.

Good experience although the boarding gate is at the terminal extension hence need to leave lounge to head over earlier.

Thai Royal First is very good. Easy check in , Private room in the first class lounge and escort from ticketing to the plane. Once on board crew was very polite, food was outstanding, and the ride was smooth as silk. Restrooms were especially clean. Great Experience

I'm not interested in improving the airline. Therefore, I won't explain this in more detail. Next time I'll try a different one.

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.

Food and welcome services were good , however we experienced issues with the entertainment system and poor headsets

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.

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.

I was in a bulkhead seat and my tray table wasn't level. Eating was difficult.

Nice lounge but had a 5 hour layover which is a lot

Flight on time and priority boarding worked. I travelled economy although business was available as no flights are cheap these days and at least with BA loyalty card I get a baggage allowance for nothing. That made the flight comparable or even cheaper than the ‘budget’ alternative. As for catering and entertainment - not on a BA short haul economy ! At least we were offered biscuits and water! Catering for economy short haul has been reduced to the minimum - no tea or coffee or other drinks than water (from a large bottle with a paper cup on offer). They will say this is better for the environment, which it is, but proper waste management is still needed for empty packets etc. so actually it’s a money saver.

Audi visual not working for a whole group of seats in first class. How does a plane leave the main hub in such poor condition? How much that we can’t see so immediately is also compromised?

main meals are horrible but then you dont fly for the food

It was good. Couldn’t Check in online and select seats

It was great. Enough space and room for legs . Great service to.

⭐ British Airways Review — A Journey of Highs, Lows, and Lessons ⭐ I recently flew Business Class round-trip from Boston to Mumbai with British Airways, and my experience was a tale of two extremes — from disappointment to exceptional service, and then back to inconsistency. Boston → London: A Surprisingly Poor Start My journey began on a disappointing note. On a 6-hour Business Class flight, I was surprised to discover that there wasn’t a single proper vegetarian meal option available. I was offered a few bakery items only after repeatedly requesting something to eat. The flight attendant shrugged, offered no solution, and eventually — quite literally — threw some bread at me after much delay. This was not only disheartening, it was extremely surprising given my wonderful Business Class experience with BA last year. I stepped off that flight genuinely hungry and had to make a mad dash to the lounge just to get a proper meal. London → Mumbai: A Complete Turnaround The next sector restored my faith in British Airways. The entire crew was warm, welcoming, attentive, and genuinely caring. A special shoutout to Phiroze and the entire team serving the Business Class cabin — their professionalism, hospitality, and thoughtful service were extraordinary. They truly embodied what makes British Airways a global leader, and I am deeply grateful for the experience they provided. This is the BA I know and love. Mumbai → London: A Strange Meal Schedule This sector was generally fine, but the meal timing was puzzling. Lunch at 10:30 AM — for a Business cabin — felt unusual, and most passengers, including myself, barely touched it. The rest of the service was smooth, but the scheduling definitely needs a rethink. London → Boston: Mixed Experience Again The flight itself was decent, but the Business Lounge at Heathrow for this leg was a letdown. Arrived during lunch hours: no hot vegetarian options available Lounge area: dirty dishes everywhere Even after politely alerting the staff, the dishes were ignored and left uncleared For a premium cabin passenger — and at one of the world’s busiest international hubs — this was disappointing. Overall Impression My journey with British Airways felt inconsistent — two great sectors sandwiched between two that fell short of the BA standard. When BA is good, it is world-class. When it misses, the gap is noticeable. I genuinely hope the airline takes this feedback as constructive insight. I continue to believe in British Airways, and I commend the outstanding crew on the London → Mumbai sector — they were the highlight of my entire trip. With a little more focus on vegetarian meal availability, lounge service, and consistency across crews, BA can ensure every Business Class passenger experiences the premium journey they promise.

We were in business class and I had seat # 1. This was a night flight and after dinner was served, lights were dimmed and I went to sleep. The crew were loud and noisy so I didn’t get much sleep. I expect the crew to enjoy themselves but would Appreciate some decency in staying quiet while the passengers sleep

Have travelled business class with other airlines who profess to be the best in the world. They can however not beat the service and comfort that BA provide.

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.