How long is the flight from London Heathrow Airport to Siem Reap?

A quick flight from London Heathrow Airport to Siem Reap can take about 16h 15m. Vietnam Airlines provides one of the quickest options available for as low as £761. Airlines will cover a distance of 6106 mi.

What are the cheapest airlines flying from London Heathrow Airport to Siem Reap round-trip?

Cheapflights users have booked flights from London Heathrow Airport to Siem Reap round-trip from £532. Other airlines that can offer you cheap pricing are Vietnam Airlines, from £608, and Singapore Airlines, from £655. These flights start at 33% lower than the current average price 3 months from now.

What are the cheapest airlines to fly from London Heathrow Airport to Siem Reap one-way?

The cheapet airlines for a one-way flight from London Heathrow Airport to Siem Reap are Austrian Airlines (£374), Vietnam Airlines (£446), and Singapore Airlines (£497).

In terms of precipitation, rainfall in Siem Reap ranges from 0.0 - 260.0 inches per month. September is typically the wettest month, when rainfall can reach 260.0 mm. January is typically the driest time to visit Siem Reap when rainfall is around 0.0 mm.

If weather is an important factor for your trip to Siem Reap, use this chart to help with planning. For those seeking warmer temperatures, April is the ideal time of year to visit, when temperatures reach an average of 29.0 C. Travellers hoping to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 24.0 C).

What are the most popular airlines that fly from London Heathrow Airport to Siem Reap?

Vietnam Airlines, Singapore Airlines and Thai Airways are the most popular airlines when flying from London Heathrow Airport to Siem Reap.

What is the cheapest time of day to fly from LHR to SAI?

When flying from London Heathrow Airport to Siem Reap, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

What airport do you fly into for flights to Siem Reap from London Heathrow?

For a flight from London Heathrow to Siem Reap, you will be flying into Siem Reap–Angkor Intl. Siem Reap–Angkor Intl (SAI) is just 24.7 mi from the center of the city. Siem Reap–Angkor Intl is the only Siem Reap airport and it handles 0 inbound flights from London Heathrow per day. 4 airlines have flights to Siem Reap–Angkor Intl from London Heathrow on a regular basis.

Can I find deals for flights from Heathrow to Siem Reap that include hotel bookings?

Yes. In addition to deals on Heathrow to Siem Reap flights, Cheapflights offers holiday packages that include both flights and hotel.

How can I find direct flights from Heathrow to Siem Reap?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Heathrow to Siem Reap.

Can I find deals for business class flights from Heathrow to Siem Reap?

Yes. Cheapflights offers flight deals from Heathrow to Siem Reap by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

£345+ Cheap Flights from London Heathrow Airport to Siem Reap, Cambodia

Cheap flight deals from Heathrow to Siem Reap

Enter your travel dates to find the best prices.

Cheapest

Best

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Cheapest flights from Heathrow to Siem Reap
Explore the most affordable flight options available from Heathrow to Siem Reap. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 27 August 2026.

Mon 21/921:20 -

3 stops40h 50m

Tue 15/1222:00 -

3 stops50h 30m

Deal found 26/8£617

Thu 10/908:45 -

2 stops28h 10m

Wed 7/1009:40 -

2 stops28h 15m

Deal found 25/8£654

Wed 9/922:40 -

2 stops37h 25m

Wed 7/1019:10 -

1 stop27h 45m

Deal found 26/8£655

Mon 21/922:10 -

2 stops37h 55m

Tue 15/1220:30 -

1 stop17h 45m

Deal found 26/8£687

Thu 3/1206:00 -

2 stops29h 45m

Mon 14/1209:55 -

2 stops18h 45m

Deal found 27/8£689

Thu 1/1009:35 -

2 stops23h 15m

Sun 11/1019:05 -

2 stops30h 15m

Deal found 24/8£693

Wed 9/913:50 -

2 stops23h 05m

Wed 7/1009:40 -

2 stops18h 05m

Deal found 25/8£694

Tue 1/1207:40 -

2 stops19h 15m

Thu 10/1209:55 -

2 stops18h 45m

Deal found 23/8£695

Tue 17/1112:05 -

2 stops23h 40m

Mon 30/1116:50 -

2 stops22h 15m

Deal found 26/8£701

Fri 11/912:35 -

2 stops26h 35m

Tue 6/1018:05 -

1 stop28h 50m

Deal found 25/8£701

Mon 31/806:00 -

2 stops30h 55m

Fri 11/909:40 -

2 stops38h 10m

Deal found 22/8£706

Sun 25/1021:10 -

2 stops38h 35m

Wed 4/1118:40 -

1 stop19h 35m

Deal found 23/8£707

Find flight deals from Heathrow to Siem Reap

Round-trip from	£617
One-way from	£345
Popular in	July
Cheapest in	March
Average price	£916

China Eastern
21/9-15/12
6 total stops
91h 20m total
London to Siem Reap

Search Deals

6/9
2 total stops
39h 40m total
London to Siem Reap

Search Deals

Highest demand for flights based on searches. 6% potential increase in price (£43 potential increase over avg. return price).

Search Deals

Cheapest flight prices on average. 1% potential price decrease (£7 potential savings vs. average return price).

Search Deals

Average for round-trip flights in August 2026

Search Deals

Cheapflights Fare Finder

Use the filters below to find and compare flights from London Heathrow Airport to Siem Reap that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest return flight

LondonSiem Reap

LHR London Heathrow - SAI Siem Reap–Angkor Intl

LHRSAI

London Heathrow

Mon 7/9

18:55-17:10

1 stop16h 15m

Siem Reap–Angkor Intl

Sun 4/10

18:05-17:05

1 stop29h 00m

£761

LondonSiem Reap

LHR London Heathrow - SAI Siem Reap–Angkor Intl

LHRSAI

London Heathrow

Sun 6/9

19:50-17:10

1 stop15h 20m

Siem Reap–Angkor Intl

Mon 5/10

15:00-17:50

1 stop32h 50m

£765

LondonSiem Reap

LHR London Heathrow - SAI Siem Reap–Angkor Intl

LHRSAI

London Heathrow

Thu 12/11

11:00-20:30

1 stop26h 30m

Siem Reap–Angkor Intl

Thu 19/11

17:55-07:15

1 stop20h 20m

£767

Fastest return journey

LondonSiem Reap

LHR London Heathrow - SAI Siem Reap–Angkor Intl

LHRSAI

London Heathrow

Thu 1/10

18:55-18:20

1 stop17h 25m

Siem Reap–Angkor Intl

Wed 14/10

22:35-16:55

1 stop24h 20m

£768

LondonSiem Reap

LHR London Heathrow - SAI Siem Reap–Angkor Intl

LHRSAI

London Heathrow

Thu 3/12

11:00-20:30

1 stop26h 30m

Siem Reap–Angkor Intl

Mon 14/12

18:40-07:15

1 stop19h 35m

£780

LondonSiem Reap

LHR London Heathrow - SAI Siem Reap–Angkor Intl

LHRSAI

London Heathrow

Tue 10/11

11:00-20:30

1 stop26h 30m

Siem Reap–Angkor Intl

Thu 3/12

17:05-07:15

2 stops21h 10m

£784

LondonSiem Reap

LHR London Heathrow - SAI Siem Reap–Angkor Intl

LHRSAI

London Heathrow

Mon 5/10

14:25-21:30

2 stops25h 05m

Siem Reap–Angkor Intl

Thu 15/10

23:50-20:15

2 stops26h 25m

£792

LondonSiem Reap

LHR London Heathrow - SAI Siem Reap–Angkor Intl

LHRSAI

London Heathrow

Sun 27/9

22:15-21:30

2 stops41h 15m

Siem Reap–Angkor Intl

Mon 25/1

13:20-07:10

2 stops24h 50m

£799

LondonSiem Reap

LHR London Heathrow - SAI Siem Reap–Angkor Intl

LHRSAI

London Heathrow

Tue 10/11

11:00-20:30

1 stop26h 30m

Siem Reap–Angkor Intl

Sat 5/12

21:30-07:15

2 stops40h 45m

£828

Cheapest one-way

LondonSiem Reap

LHR London Heathrow - SAI Siem Reap–Angkor Intl

LHRSAI

London Heathrow

Mon 22/2

19:50-19:30

2 stops40h 40m

£355

Flights are sorted by cheapest return flights first.

Deals found on 27/8

Showing 1-10 of 15 resultsSorted by cheapest first

Best time to book a flight from Heathrow to Siem Reap

Have a flexible travel schedule? Discover the best time to fly to Siem Reap from Heathrow with our price prediction graph.

LHR-SAI

Estimated return price

Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from London Heathrow Airport to Siem Reap

What’s the top stopover airport for flights from London Heathrow Airport to Siem Reap?

Singapore (SIN) – chosen by Cheapflights users on 65% of one-stop itineraries from London Heathrow Airport to Siem Reap on Cheapflights.

What’s the cheapest stopover airport for flights from London Heathrow Airport to Siem Reap?

Singapore (SIN) is the most affordable one-stop option, with an average return flight price of £789.

What’s the fastest stopover option from London Heathrow Airport to Siem Reap?

Flights via Bangkok (BKK) have the shortest average one-way travel time for one-stop routes: 13h 55m.

Which airport typically offers the quickest stopover for flights from London Heathrow Airport to Siem Reap?

Flights via Ho Chi Minh City (SGN) offer the fastest connection on this route, with an average stopover time of 1h 53m.

Reviews of airlines servicing Siem Reap

Read reviews from past customers who have flown with Singapore Airlines,Thai Airways, andVietnam Airlines from London Heathrow Airport to Siem Reap. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.

Singapore Airlines

8.2

Very Good

1,588 reviews

Check prices

Reviews

1 / 20

8.0

Excellent

Matt,Jun 2026

SIN - CMB

Crew were flat or busy but so awesome and polite. There was one guy, prob the senior crew member, looked and acted way too serious and too important to smile and say hello

Singapore Airlines

8.2

Very Good

1,588 reviews

Singapore Airlines

8.2

Very Good

1,588 reviews

Check prices

Reviews

1 / 20

8.0

Excellent

Matt,Jun 2026

SIN - CMB

Crew were flat or busy but so awesome and polite. There was one guy, prob the senior crew member, looked and acted way too serious and too important to smile and say hello

Thai Airways

7.9

Good

417 reviews

Singapore Airlines

8.2

Very Good

1,588 reviews

Check prices

Reviews

1 / 20

8.0

Excellent

Matt,Jun 2026

SIN - CMB

Crew were flat or busy but so awesome and polite. There was one guy, prob the senior crew member, looked and acted way too serious and too important to smile and say hello

Vietnam Airlines

7.7

Good

286 reviews

Singapore Airlines

8.2

Very Good

1,588 reviews

Check prices

Reviews

1 / 20

8.0

Excellent

Matt,Jun 2026

SIN - CMB

Crew were flat or busy but so awesome and polite. There was one guy, prob the senior crew member, looked and acted way too serious and too important to smile and say hello

Austrian Airlines

7.6

Good

951 reviews

Singapore Airlines

8.2

Very Good

1,588 reviews

Check prices

Reviews

1 / 20

8.0

Excellent

Matt,Jun 2026

SIN - CMB

Crew were flat or busy but so awesome and polite. There was one guy, prob the senior crew member, looked and acted way too serious and too important to smile and say hello

Related info for your journey

What airport do you fly into for flights to Siem Reap from London Heathrow?
For a flight from London Heathrow to Siem Reap, you will be flying into Siem Reap–Angkor Intl. Siem Reap–Angkor Intl (SAI) is just 24.7 mi from the center of the city. Siem Reap–Angkor Intl is the only Siem Reap airport and it handles 0 inbound flights from London Heathrow per day. 4 airlines have flights to Siem Reap–Angkor Intl from London Heathrow on a regular basis.
How long is the flight from London Heathrow Airport to Siem Reap?
A quick flight from London Heathrow Airport to Siem Reap can take about 16h 15m. Vietnam Airlines provides one of the quickest options available for as low as £761. Airlines will cover a distance of 6106 mi.
What are the cheapest airlines flying from London Heathrow Airport to Siem Reap round-trip?
Cheapflights users have booked flights from London Heathrow Airport to Siem Reap round-trip from £532. Other airlines that can offer you cheap pricing are Vietnam Airlines, from £608, and Singapore Airlines, from £655. These flights start at 33% lower than the current average price 3 months from now.
What are the cheapest airlines to fly from London Heathrow Airport to Siem Reap one-way?
The cheapet airlines for a one-way flight from London Heathrow Airport to Siem Reap are Austrian Airlines (£374), Vietnam Airlines (£446), and Singapore Airlines (£497).
Can I find deals for flights from Heathrow to Siem Reap that include hotel bookings?
Yes. In addition to deals on Heathrow to Siem Reap flights, Cheapflights offers holiday packages that include both flights and hotel.
How can I find direct flights from Heathrow to Siem Reap?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Heathrow to Siem Reap.
Can I find deals for business class flights from Heathrow to Siem Reap?
Yes. Cheapflights offers flight deals from Heathrow to Siem Reap by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

Alternative routes

Complete your trip

Flights by cabin class

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Popular flights

Alternative routes for Heathrow to Siem Reap

Gatwick to Siem Reap flights

Stansted to Siem Reap flights

London City to Siem Reap flights

Luton to Siem Reap flights

Top 4 airlines flying from Heathrow to Siem Reap

Airline	Cheapest	Average	Flexibility	On-time
Austrian Airlines	Cheapest£532	Average£679	FlexibilityNo cancel fee	On-time78%	Search Austrian Airlines flights
Vietnam Airlines	Cheapest£608	Average£804	FlexibilityNo cancel fee	On-time81%	Search Vietnam Airlines flights
Singapore Airlines	Cheapest£655	Average£773	FlexibilityNo cancel fee	On-time81%	Search Singapore Airlines flights
Thai Airways	Cheapest£878	Average£1,008	FlexibilityNo cancel fee	On-time77%	Search Thai Airways flights

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How does Cheapflights help users find flights from Heathrow to Siem Reap?

When you search for this flight from Heathrow to Siem Reap, Cheapflights searches on 900+ travel sites to save you time finding great flight deals online. Additionally, we offer filter features so you can choose a preferred cabin class or airline, see different price ranges, and much more so you can book the flight for you.

Why should you use Cheapflights to find cheap flight tickets from Heathrow to Siem Reap?

It’s simple! Cheapflights, which is free to use for everyone, saves millions of users time and money every year by helping them find the cheapest and most suitable flights from Heathrow to Siem Reap.

Can Cheapflights find flights from Heathrow to Siem Reap with no change fees?

Need flexible booking options for your flight to Siem Reap from Heathrow? Don’t worry, Cheapflights have you covered. Use our search filter to only show flights with no change fees.

Can Cheapflights notify me if prices for flights from Heathrow to Siem Reap become cheaper?

Not ready to book yet? You can track prices for flights from Heathrow to Siem Reap on Cheapflights with our Price Alert feature and get notified when better prices are available.

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Cheap flights from London Heathrow Airport to Siem Reap, Cambodia from £345

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 6/9. Fares are subject to change and may not be available on all flights or dates of travel.

Cheap flight deals from Heathrow to Siem Reap

Cheapest flights from Heathrow to Siem ReapExplore the most affordable flight options available from Heathrow to Siem Reap. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 27 August 2026.

Explore the most affordable flight options available from Heathrow to Siem Reap. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 27 August 2026.

Best flights from Heathrow to Siem ReapDiscover carefully curated flight deals from Heathrow to Siem Reap that have cost, travel time, and stopovers in mind to ensure you get the best travel experience. Data last updated 27 August 2026.

Discover carefully curated flight deals from Heathrow to Siem Reap that have cost, travel time, and stopovers in mind to ensure you get the best travel experience. Data last updated 27 August 2026.

Last-minute flights from Heathrow to Siem ReapDiscover last-minute flight deals from Heathrow to Siem Reap. Data last updated 27 August 2026 and is based on user searches.

Discover last-minute flight deals from Heathrow to Siem Reap. Data last updated 27 August 2026 and is based on user searches.

One-way flights from Heathrow to Siem ReapSearch for one-way flight options from Heathrow to Siem Reap. Find affordable one-way fares based on user searches. Data last updated 27 August 2026.

Search for one-way flight options from Heathrow to Siem Reap. Find affordable one-way fares based on user searches. Data last updated 27 August 2026.

Find flight deals from Heathrow to Siem Reap

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One-way from

Popular in

Cheapest in

Average price

Cheapflights Fare Finder

Use the filters below to find and compare flights from London Heathrow Airport to Siem Reap that are best for you.

Best time to book a flight from Heathrow to Siem Reap

Have a flexible travel schedule? Discover the best time to fly to Siem Reap from Heathrow with our price prediction graph.

Cheapflights Insights

What’s the top stopover airport for flights from London Heathrow Airport to Siem Reap?

Singapore (SIN) – chosen by Cheapflights users on 65% of one-stop itineraries from London Heathrow Airport to Siem Reap on Cheapflights.

What’s the cheapest stopover airport for flights from London Heathrow Airport to Siem Reap?

Singapore (SIN) is the most affordable one-stop option, with an average return flight price of £789.

What’s the fastest stopover option from London Heathrow Airport to Siem Reap?

Flights via Bangkok (BKK) have the shortest average one-way travel time for one-stop routes: 13h 55m.

Which airport typically offers the quickest stopover for flights from London Heathrow Airport to Siem Reap?

Flights via Ho Chi Minh City (SGN) offer the fastest connection on this route, with an average stopover time of 1h 53m.

Reviews of airlines servicing Siem Reap

Related info for your journey

What airport do you fly into for flights to Siem Reap from London Heathrow?

How long is the flight from London Heathrow Airport to Siem Reap?

What are the cheapest airlines flying from London Heathrow Airport to Siem Reap round-trip?

What are the cheapest airlines to fly from London Heathrow Airport to Siem Reap one-way?

Can I find deals for flights from Heathrow to Siem Reap that include hotel bookings?

How can I find direct flights from Heathrow to Siem Reap?

Can I find deals for business class flights from Heathrow to Siem Reap?

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Heathrow to Siem Reap

See prices for flight routes from nearby airports that may be better suited for you.

Complete your trip

Complete your trip to Siem Reap by adding a car hire and/or hotel booking to your travel itinerary.

Search flights from Heathrow to Siem Reap by cabin class

Find flights from Heathrow to Siem Reap, based on your preferred cabin class, be it economy, premium economy, business, or first class.

Heathrow and Siem Reap flights

Browse other Heathrow and Siem Reap flight options. Last updated on 27 August 2026.

Other flights from Heathrow

Browse through other flights departing from Heathrow. Flights are based on user searches made on Cheapflights and were last updated on 27 August 2026.

Popular flight searches

Check out other popular destinations found by fellow travellers in 2026

Top 4 airlines flying from Heathrow to Siem Reap

Fly with Cheapflights

How does Cheapflights help users find flights from Heathrow to Siem Reap?

Why should you use Cheapflights to find cheap flight tickets from Heathrow to Siem Reap?

Can Cheapflights find flights from Heathrow to Siem Reap with no change fees?

Can Cheapflights notify me if prices for flights from Heathrow to Siem Reap become cheaper?

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Book with Flexibility

Travel Smart

Cheapest flights from Heathrow to Siem Reap
Explore the most affordable flight options available from Heathrow to Siem Reap. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 27 August 2026.

Best flights from Heathrow to Siem Reap
Discover carefully curated flight deals from Heathrow to Siem Reap that have cost, travel time, and stopovers in mind to ensure you get the best travel experience. Data last updated 27 August 2026.

Last-minute flights from Heathrow to Siem Reap
Discover last-minute flight deals from Heathrow to Siem Reap. Data last updated 27 August 2026 and is based on user searches.

One-way flights from Heathrow to Siem Reap
Search for one-way flight options from Heathrow to Siem Reap. Find affordable one-way fares based on user searches. Data last updated 27 August 2026.