Than Sadet Waterfall, Koh Phangan - the Royal Waterfall in the national park

Than Sadet Waterfall is one of the most interesting natural and historical sites on Koh Phangan. Deep in the tropical forest on the east of the island, a stream flows between huge granite boulders, forming a series of small cascades, natural pools and rock steps. Unlike waterfalls where the water drops from a great height at a single point, here the experience is of a mountain stream winding its way between the rocks and the greenery.

The waterfall also has an unusual story: kings of Thailand visited it over the years, and the royal initials carved into the rocks have made it a site of historical and cultural importance.

Than Sadet lies within Than Sadet-Ko Pha-ngan National Park, not far from the beaches of Thong Nai Pan. You can combine it with a day out in east Koh Phangan, alongside the beaches and bays of the area.

What does Than Sadet Waterfall look like?

The scenery at Than Sadet is a little different from the familiar picture of a big tropical waterfall, where a column of water drops from a cliff into a deep pool.

Here the water flows between large, rounded granite boulders in shades of grey and brown. At some points it drops down short rock steps, churning up white foam, and at others it collects in natural pools between the stones.

The rocks themselves are a central part of the scenery. Some are enormous, and their rounded shapes form natural steps and ledges beside the stream.

All around grows dense tropical forest, with trees, shrubs and greenery enclosing the watercourse.

What do you see at the viewing point?

When we visited on 20 February 2025, the stream was flowing between the granite boulders and forming several small cascades. The water broke over the rocks, creating white foam, and between the natural steps there were pools and narrow channels of water.

Even in February, a time considered part of the dry season in the area, there was a good flow at this point.

This is an important detail, because waterfalls in Thailand can look very different from season to season, and even from week to week depending on how much rain has fallen.

Is it a big waterfall?

Not in the sense of a tall, dramatic vertical waterfall.

Than Sadet is a system of small cascades and pools along a stream bed, and its beauty lies in the combination of rock formations, flowing water and the forest around it.

If you are expecting one big waterfall, the scene may surprise you. On the other hand, if you love streams, rocks and natural scenery, you may find this a particularly interesting site.

Why is Than Sadet called the "Royal Waterfall"?

The meaning of the name Than Sadet is linked to the royal status of the place and to the visits of the King of Siam, as Thailand was formerly known.

In 1888 King Chulalongkorn, Rama V, came to the area and gave the waterfall its name.

The king was known for his journeys around the kingdom, and between 1888 and 1909 he visited Koh Phangan 14 times, according to local historical records.

The waterfall became one of the places associated with his visits to the island.

The royal initials carved in the rock

One of the most interesting historical details at Than Sadet is the royal inscriptions carved into the rocks along the stream and in the area where it flows into the sea.

Rama V left his royal initials here, known in Thai as the monogram จปร.

Later, other members of the royal family also came to the area, including Rama VI, Rama VII and his consort Queen Rambai Barni, as well as Rama IX.

The inscriptions in the rocks are tangible evidence of the historical link between the Thai royal family and the place.

Why is the stream considered special in Thai culture?

The stream is attributed ceremonial and traditional significance, connected with the royal visits and with the use of its water.

This connection has made Than Sadet more than a nature site: it is a place that combines scenery, history and royal heritage.

It is important to treat the historical inscriptions with respect, not to carve anything into the rocks and not to damage the natural surroundings.

Than Sadet-Ko Pha-ngan National Park

The waterfall lies within Than Sadet-Ko Pha-ngan National Park, which was declared a national park in 2018.

The park covers forested, hilly areas of Koh Phangan and includes stream systems, waterfalls, viewpoints and stretches of tropical forest.

Than Sadet is one of its best-known sites, but the park is not limited to this stream valley alone.

Phaeng Waterfall, in another part of Koh Phangan, also belongs to the park's network of natural sites.

A stream that winds down to the sea

The Than Sadet stream runs for about 2.5-3 kilometres between the forested hills of the east of the island, down to the bay of Ao Than Sadet.

Along the stream there are stretches where the water tumbles between the rocks, alongside natural pools and points where the channel widens.

There is no need to treat the length of the stream as a trail you have to complete. You can visit one accessible point and enjoy it, or spend more time in the surroundings depending on the terrain and the access allowed.

Can you swim at the waterfall?

Natural pools form between the rocks in various parts of the Than Sadet stream, but not every pool is suitable for swimming.

The depth of the water, the strength of the flow and access to the pools vary depending on the spot and the state of the stream.

Wet granite can be very slippery, especially where the water flows over sloping surfaces.

We do not recommend jumping in without knowing how deep the pool is and what lies beneath the surface.

After heavy rain, take particular care with strong currents and sudden changes in water level.

If swimming is your main interest, choose a spot where entry is permitted and safe according to the park's guidance on the day.

When is the best time to visit Than Sadet Waterfall?

The flow of water at Than Sadet changes through the year depending on how much rain falls in the area.

In the rainy season

After rainy periods the flow can be stronger and the cascades more impressive.

On the other hand, wet rocks, slippery paths and strong currents can make the visit more difficult.

In the dry season

In the dry season the flow can weaken in parts of the stream.

That does not mean the waterfall always dries up completely, though.

On 20 February 2025, for example, there was a lovely flow between the rocks, despite it being a relatively dry time of year.

This shows that the season alone does not tell you exactly how the waterfall will look on the day you visit.

What time of day should you go?

We recommend planning your visit in daylight, especially if you intend to walk along the stream or between different points.

It is important to leave enough time to get back to your vehicle comfortably before dark.

How to get to Than Sadet Waterfall

Than Sadet Waterfall is in east Koh Phangan, along the road leading towards Than Sadet Beach and the bays of Thong Nai Pan.

You can reach the area by car or local transport, and continue from the appropriate access point towards the stream.

One thing that is important to understand is that the stream has more than one visiting point. So when navigating, it is worth distinguishing between the park entrance, the access points to the waterfall and Than Sadet Beach.

Getting there by hire car

A hire car lets you combine your visit to the waterfall with beaches and other attractions in the east of the island.

Some of the roads in the area are hilly, so drive carefully and use up-to-date navigation.

Getting there by scooter

Experienced riders can reach some parts of the park by scooter, depending on the state of the road.

Bear in mind that steep roads and wet surfaces can be dangerous, especially if you are not an experienced rider.

Do you need to walk far?

Not necessarily.

Because the waterfall is a series of cascades along the stream, how far you walk depends on the access point and the section you want to visit.

If you want a short stop, you can choose one of the accessible visiting points, depending on which trails are open and conditions in the park.

If you want to see more of the stream, allow for rocky ground, natural steps and sections that can be slippery.

How long should you spend at the waterfall?

For a short visit to one of the access points, allow around half an hour to an hour, depending on how you get there and how long you want to spend by the water.

If you want to walk along more of the stream, you can spend longer.

That said, Than Sadet is not necessarily an attraction that needs half a day on its own.

If you are planning to see several places in east Koh Phangan, you can fit it in as a stop during a day trip.

Than Sadet Beach - from the stream to the sea

The stream ends at the bay of Ao Than Sadet, home to Than Sadet Beach.

The bay is surrounded by forested hills and combines a tropical beach with the hilly scenery of east Koh Phangan.

The link between the waterfall and the beach is both geographical and historical: the stream flows towards the sea, and some of the evidence of the royal visits is in the area where it meets the sea.

If you have enough time in the area, you could consider combining the waterfall with a visit to the beach.

It is important to tell the two apart: the waterfall is a natural site along the stream, while the beach is a separate destination for time by the sea.

How to fit Than Sadet into a day out on Koh Phangan

One of the advantages of the waterfall's location is that you can combine it with other places in the east of the island, rather than making a special trip just for a short stop.

One possible route takes in Than Sadet Waterfall and the Thong Nai Pan area, home to two bays: Thong Nai Pan Noi and Thong Nai Pan Yai.

On 20 February 2025 we combined our visit to the waterfall with stops in the Thong Nai Pan area.

A stop at Dreamland Resort

On Thong Nai Pan Yai beach is Dreamland Resort, a resort with a large pool facing the sea and a bar beside the pool area.

You can take a look at the resort as part of a visit to the beach, depending on the property's entry policy and services.

Our Dreamland Resort review ›

Food in Thong Nai Pan

In the Thong Nai Pan Noi area there is also a local food court offering a range of dishes, an interesting option for a meal away from the hotel restaurants.

That way you can combine nature, beaches and local food on the same day, without turning the waterfall visit into a trip of its own.

Our Thong Nai Pan food guide ›

Our Thong Nai Pan guide ›

What to know before you go

• Type of waterfall: it is a series of small cascades and natural pools, not one big vertical waterfall.
• Length of visit: you can make do with a short stop at one point, or spend more time walking along parts of the stream.
• Shoes: we recommend shoes with good grip. The rocks are slippery when wet.
• Water and kit: bring drinking water, especially on a hot day.
• Seasons: the amount of water changes with the rainfall. A good flow was recorded here even in February 2025.
• Entrance fees: entry to parts of the park may involve a fee. According to travellers' reports, foreign visitors paid around 100 to 200 baht (about $3-6 / €3-5) per person. There is no official published price, so check on the spot and bring cash.
• Looking after the site: do not damage the rocks, the plants or the historical royal inscriptions.

Is Than Sadet Waterfall worth visiting?

Than Sadet is an interesting natural site, mainly because of the combination of the stream, the big granite boulders, the forest and its unusual history.

It is not the waterfall for anyone expecting a huge cascade dropping from a high cliff, but for those who appreciate a tropical stream flowing between natural rock steps.

The link with the Thai royal family adds a dimension not every nature site has, and also makes it a point of historical interest.

If you are planning a day out in east Koh Phangan, especially around Thong Nai Pan, Than Sadet is an interesting stop to fit in along the way.

For more destinations, beaches and attractions around the island: our complete Koh Phangan guide.