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

A quick flight from London Heathrow Airport to Region of Siem Reap can take about 31h 30m. Etihad Airways provides one of the quickest options available for as low as £597. Airlines will cover a distance of 6106 mi. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.

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

£451 is the cheapest one-way deal found within the past few days, from Vietnam Airlines. You may also be able to find cheap deals on Singapore Airlines and Thai Airways, with prices starting from £514 and £557, respectively.

In terms of precipitation, rainfall in Region of 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 Region of Siem Reap when rainfall is around 0.0 mm.

If weather is an important factor for your trip to Region of 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 Region of Siem Reap?

The most popular airlines flying from London Heathrow Airport to Region of Siem Reap are Singapore Airlines, Vietnam Airlines and Thai Airways. Something to consider prior to booking your flight.

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

When flying from London Heathrow Airport to Region of 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.

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.

£376+ Cheap Flights from London Heathrow Airport to Siem Reap

Q: How much does it cost for a return flight from London Heathrow Airport to Region of Siem Reap?

Airfare is below average for this route at the moment. London Heathrow Airport to Region of Siem Reap flights typically cost between £838 and £735 in June. The cheapest return flight price found within the last 3 days was £597 on Etihad Airways (15 Jun-30 Jun).

Cheap flight deals from Heathrow to Siem Reap

Enter your travel dates to find the best prices.

Cheapest

Best

Last-minute

One-way

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 1 June 2026.

Mon 15/614:45

LHR

SAI

2 stops38h 30m

Etihad Airways

Tue 30/615:10

SAI

LHR

2 stops33h 35m

Etihad Airways

Deal found 27/5£597

Wed 24/621:45

LHR

SAI

2 stops31h 30m

Etihad Airways

Fri 26/619:20

SAI

LHR

2 stops29h 25m

Etihad Airways

Deal found 28/5£599

Tue 16/609:30

LHR

SAI

2 stops26h 20m

Etihad Airways

Tue 30/615:10

SAI

LHR

2 stops33h 35m

Etihad Airways

Deal found 27/5£612

Thu 18/614:45

LHR

SAI

2 stops38h 30m

Etihad Airways

Thu 2/715:10

SAI

LHR

2 stops21h 50m

Etihad Airways

Deal found 27/5£617

Mon 15/621:45

LHR

SAI

2 stops31h 30m

Etihad Airways

Sat 4/715:10

SAI

LHR

2 stops21h 50m

Etihad Airways

Deal found 27/5£628

Tue 16/609:30

LHR

SAI

2 stops19h 45m

Etihad Airways

Sat 4/715:10

SAI

LHR

2 stops33h 35m

Etihad Airways

Deal found 27/5£643

Mon 22/620:45

LHR

SAI

2 stops32h 30m

Etihad Airways

Thu 25/615:10

SAI

LHR

2 stops33h 35m

Etihad Airways

Deal found 28/5£644

Wed 29/714:45

LHR

SAI

2 stops38h 30m

Etihad Airways

Tue 18/815:10

SAI

LHR

2 stops33h 35m

Etihad Airways

Deal found 29/5£655

Wed 29/720:45

LHR

SAI

2 stops32h 30m

Etihad Airways

Sun 16/819:20

SAI

LHR

2 stops29h 25m

Etihad Airways

Deal found 30/5£657

Wed 29/720:45

LHR

SAI

2 stops38h 10m

Etihad Airways

Thu 20/815:10

SAI

LHR

2 stops29h 55m

Etihad Airways

Deal found 29/5£672

Tue 10/1121:00

LHR

SAI

2 stops41h 00m

China Eastern

Thu 3/1222:00

SAI

LHR

3 stops50h 30m

China Eastern

Deal found 29/5£695

Find flight deals from Heathrow to Siem Reap

Round-trip from	£597
One-way from	£376
Popular in	December
Cheapest in	September
Average price	£845

Etihad Airways
15/6-30/6
4 total stops
72h 05m total
London to Siem Reap

Search Deals

Etihad Airways
13/6
2 total stops
31h 30m total
London to Siem Reap

Search Deals

Highest demand for flights based on searches. 7% potential increase in price (£49 potential increase over avg. return price).

Search Deals

Cheapest flight prices on average. 3% potential price decrease (£24 potential savings vs. average return price).

Search Deals

Average for round-trip flights in June 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 - SAI

LHRSAI

London Heathrow

Fri 19/6

21:45-17:50

2 stops38h 05m

Siem Reap–Angkor Intl

Tue 30/6

19:20-18:45

2 stops29h 25m

£597

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Wed 17/6

21:45-11:15

2 stops31h 30m

Siem Reap–Angkor Intl

Fri 3/7

19:20-07:00

2 stops41h 40m

£597

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Wed 29/7

20:45-11:15

2 stops32h 30m

Siem Reap–Angkor Intl

Tue 18/8

19:20-18:45

2 stops29h 25m

£657

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Tue 10/11

21:00-21:00

3 stops41h 00m

Siem Reap–Angkor Intl

Sat 5/12

22:00-17:30

2 stops50h 30m

£698

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Mon 29/6

20:45-11:15

2 stops32h 30m

Siem Reap–Angkor Intl

Mon 20/7

12:55-15:05

2 stops32h 10m

£724

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Sun 21/6

09:30-14:20

2 stops22h 50m

Siem Reap–Angkor Intl

Mon 29/6

09:40-07:00

2 stops27h 20m

£761

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Sat 20/6

21:45-11:15

2 stops31h 30m

Siem Reap–Angkor Intl

Mon 29/6

12:55-07:00

2 stops24h 05m

£761

Fastest return journey

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Tue 23/6

09:30-11:15

2 stops19h 45m

Siem Reap–Angkor Intl

Wed 24/6

19:35-18:45

2 stops29h 10m

£770

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Wed 19/8

16:50-21:30

2 stops22h 40m

Siem Reap–Angkor Intl

Wed 16/9

12:55-12:25

2 stops29h 30m

£796

Cheapest one-way

LondonSiem Reap

LHR - SAI

LHRSAI

London Heathrow

Sat 13/6

21:45-11:15

2 stops31h 30m

£376

Flights are sorted by cheapest return flights first.

Deals found on 29/5

Showing 1-10 of 16 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

LHR-KHSI

LHR-SAI

What is the cheapest month to book a flight from London Heathrow Airport to Region of Siem Reap?

Currently, March is the cheapest month in which you can book a flight from London Heathrow Airport to Region of Siem Reap (average of £538). Flying from London Heathrow Airport to Region of Siem Reap in August is currently the most expensive (average of £1,023). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

How much does it cost for a return flight from London Heathrow Airport to Region of Siem Reap?

Reviews of airlines servicing Siem Reap

Get a feel of what it's like to fly with Singapore Airlines,Thai Airways, andVietnam Airlines from London Heathrow Airport to Siem Reap by reading reviews from past customers. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.

Singapore Airlines

8.2

Very Good

1,527 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Wee Keng,May 2026

SIN - MNL

Was upgraded to Premium Economy seat as PPS member. SQ steward team prepared birthday cake for a colleague which I requested and didn’t follow up. Great service and a great way to fly.

Singapore Airlines

8.2

Very Good

1,527 reviews

Singapore Airlines

8.2

Very Good

1,527 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Wee Keng,May 2026

SIN - MNL

Was upgraded to Premium Economy seat as PPS member. SQ steward team prepared birthday cake for a colleague which I requested and didn’t follow up. Great service and a great way to fly.

Thai Airways

7.9

Good

404 reviews

Singapore Airlines

8.2

Very Good

1,527 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Wee Keng,May 2026

SIN - MNL

Was upgraded to Premium Economy seat as PPS member. SQ steward team prepared birthday cake for a colleague which I requested and didn’t follow up. Great service and a great way to fly.

Vietnam Airlines

7.7

Good

271 reviews

Singapore Airlines

8.2

Very Good

1,527 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Wee Keng,May 2026

SIN - MNL

Was upgraded to Premium Economy seat as PPS member. SQ steward team prepared birthday cake for a colleague which I requested and didn’t follow up. Great service and a great way to fly.

Austrian Airlines

7.6

Good

921 reviews

Singapore Airlines

8.2

Very Good

1,527 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Wee Keng,May 2026

SIN - MNL

Was upgraded to Premium Economy seat as PPS member. SQ steward team prepared birthday cake for a colleague which I requested and didn’t follow up. Great service and a great way to fly.

Lufthansa

6.8

Okay

8,031 reviews

Singapore Airlines

8.2

Very Good

1,527 reviews

Check prices

Reviews

1 / 20

10.0

Excellent

Wee Keng,May 2026

SIN - MNL

Was upgraded to Premium Economy seat as PPS member. SQ steward team prepared birthday cake for a colleague which I requested and didn’t follow up. Great service and a great way to fly.

Related info for your journey

How long is the flight from London Heathrow Airport to Region of Siem Reap?
A quick flight from London Heathrow Airport to Region of Siem Reap can take about 31h 30m. Etihad Airways provides one of the quickest options available for as low as £597. Airlines will cover a distance of 6106 mi. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.
What are the cheapest airlines to fly from London Heathrow Airport to Region of Siem Reap one-way?
£451 is the cheapest one-way deal found within the past few days, from Vietnam Airlines. You may also be able to find cheap deals on Singapore Airlines and Thai Airways, with prices starting from £514 and £557, respectively.
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.
What is the cheapest month to book a flight from London Heathrow Airport to Region of Siem Reap?
Currently, March is the cheapest month in which you can book a flight from London Heathrow Airport to Region of Siem Reap (average of £538). Flying from London Heathrow Airport to Region of Siem Reap in August is currently the most expensive (average of £1,023). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

Alternative routes

Complete your trip

Direct flights to

Flights by cabin class

Other flight options

Popular flights

Alternative routes for Heathrow to Siem Reap

Heathrow to Siem Reap flights

Gatwick to Siem Reap flights

Stansted to Siem Reap flights

Gatwick to Phnom Penh flights

London City to Phnom Penh flights

London City to Siem Reap flights

Gatwick to Krong Preah Sihanouk flights

Heathrow to Krong Preah Sihanouk flights

Heathrow to Phnom Penh flights

Luton to Phnom Penh flights

Stansted to Phnom Penh flights

Luton to Siem Reap flights

Top 5 airlines flying from Heathrow to Siem Reap

Airline	Cheapest	Average	Flexibility	On-time
Austrian Airlines	Cheapest£538	Average£683	FlexibilityNo cancel fee	On-time78%	Search Austrian Airlines flights
Lufthansa	Cheapest£597	Average£767	FlexibilityNo cancel fee	On-time76%	Search Lufthansa flights
Vietnam Airlines	Cheapest£618	Average£813	FlexibilityNo cancel fee	On-time81%	Search Vietnam Airlines flights
Singapore Airlines	Cheapest£663	Average£759	FlexibilityNo cancel fee	On-time81%	Search Singapore Airlines flights
Thai Airways	Cheapest£868	Average£954	FlexibilityNo cancel fee	On-time77%	Search Thai Airways flights

Fly with Cheapflights

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

Cheapflights goes through 900+ travel sites to look for the best flight deals for flights from Heathrow to Siem Reap. Too many options? Cheapflights also provides filters for things like airlines, price ranges, and number of stops to help you make a decision easily.

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

Cheapflights helps you find that perfect flight to Siem Reap from Heathrow by searching from hundreds of airlines and agencies you know and love. We are also free to use, in case you were wondering!

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

Certainly. Search results for flights to Siem Reap from Heathrow shown to you on Cheapflights can be narrowed down with different useful search filters, which includes flexible booking options.

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

Yes, Cheapflights offers price alerts on Heathrow to Siem Reap flights so you can book your travel at the perfect time. Price Alerts can be enabled by clicking the bell icon next to the flight deals above and providing your email address where you want to receive the alerts.

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.

Cheap flights from London Heathrow Airport to Siem Reap from £376

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 13/6. 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 1 June 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 1 June 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 1 June 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 1 June 2026.

Last-minute flights from Heathrow to Siem ReapDiscover last-minute flight deals from Heathrow to Siem Reap. Data last updated 1 June 2026 and is based on user searches.

Discover last-minute flight deals from Heathrow to Siem Reap. Data last updated 1 June 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 1 June 2026.

Search for one-way flight options from Heathrow to Siem Reap. Find affordable one-way fares based on user searches. Data last updated 1 June 2026.

Find flight deals from Heathrow to Siem Reap

Keep the following information in mind while searching for Heathrow to Siem Reap flight deals. Data was last updated 1 June 2026.

Round-trip from

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

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

What is the cheapest month to book a flight from London Heathrow Airport to Region of Siem Reap?

How much does it cost for a return flight from London Heathrow Airport to Region of Siem Reap?

Reviews of airlines servicing Siem Reap

Related info for your journey

Find useful and relevant information for your journey from Heathrow to Siem Reap. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

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

What are the cheapest airlines to fly from London Heathrow Airport to Region of 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?

What is the cheapest month to book a flight from London Heathrow Airport to Region of 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.

Direct flights to

Book a non-stop flight to one of these other cities located in .

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 1 June 2026.

Popular flight searches

Check out other popular destinations found by fellow travellers in 2026

Top 5 airlines flying from Heathrow to Siem Reap

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travellers can enjoy low prices and a wide availability of flights to their desired destinations.

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?

100% Free

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 1 June 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 1 June 2026.

Last-minute flights from Heathrow to Siem Reap
Discover last-minute flight deals from Heathrow to Siem Reap. Data last updated 1 June 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 1 June 2026.