- Two boats list a dolphin program from Koh Samui: the Hilux motor yacht for ฿57,000 for 8 hours and the Lisa motor yacht for ฿145,000 for a full day.
- Both dolphin days are combined with Koh Tan, and the Hilux program also adds Koh Madsum (Pig Island) and fishing.
- Dolphin sightings are never guaranteed: the animals are wild and move freely, so the islands should be reason enough for the trip.
- A calm sea makes dolphins much easier to spot, which is one reason early starts and the drier months work best.
- Keep your distance, never chase or feed them and let the dolphins decide how close they come.
Someone at the hotel breakfast table mentions they saw dolphins off the south coast yesterday, and suddenly half the table wants to go. That is how most dolphin plans start on Koh Samui. A dolphin trip from Koh Samui is a real option, but it works best when you treat the dolphins as a lucky bonus on a good island day, not as a promise.
I have been out on enough of these days to give you the straight version: which boats actually run a dolphin program, what the day looks like, how your chances change with the sea and the time of day, and how to behave when the fins finally show up.
Can you see dolphins on a dolphin trip from Koh Samui?
Yes, dolphins are seen in the waters south of Koh Samui, around Koh Tan and the small islands off the south coast. No boat can guarantee a sighting, because these are wild animals that move with the fish and the tides, not on a schedule.
The south of the island is quieter than the busy north coast. The water between Samui and the mainland is usually shallower and calmer, and that is where crews go looking. On some days the dolphins appear within minutes; on others the boat spends an hour scanning the water and sees nothing.
That uncertainty is exactly why the dolphin programs are combined with island stops. If the dolphins do not show, you still have Koh Tan's beaches and reef, and on some programs Koh Madsum, the island known as Pig Island. If they do show, it becomes the moment everyone talks about at dinner.
So my honest advice: book a dolphin day because you want a full, relaxed day around the southern islands, and hope for the dolphins. Booked that way, nobody comes back disappointed.
Which boats run a dolphin program from Koh Samui?
Two boats list a dolphin program in their routes: the Hilux motor yacht and the Lisa motor yacht. Both are private charters with crew, and both combine the dolphin search with Koh Tan.
| Hilux Motor Yacht | Lisa Motor Yacht | |
|---|---|---|
| Dolphin program | Dolphin sightseeing, Koh Tan, Koh Madsum and fishing | Dolphin watching and Koh Tan |
| Time | 8 hours, 09:00-17:30 | 8 hours, 10:30-18:30 |
| Price per boat | ฿57,000 | ฿145,000 |
| Price covers | 1-10 people | 10 people |
| Extra guests | ฿1,500 per adult, ฿800 per child aged 11-14, children 0-10 free | ฿3,000 per person |
| Maximum guests | 20 | 13 |
| Size | 15 m (50 ft), two engines | Fairline, 43 ft (13 m), 2 double cabins |
| Food and drink | Soft drinks and water, fruits, BBQ grill | Soft drinks, fruits and snacks, lunch, 2 bottles of wine or 24 cans of beer |
The two boats sit at very different price points, and they suit different groups. Hilux is the practical choice for families and bigger groups, while Lisa is the premium version for a smaller group that wants a polished yacht day with lunch and wine included.
Other boats go to Koh Tan and Koh Madsum too, and dolphins do not check which program a boat is on. But only these two build time for looking into the day, and that makes a difference to your chances.
Hilux: the dolphin day for families and groups
Hilux runs an 8-hour dolphin program from 09:00 to 17:30 for ฿57,000, with dolphin sightseeing, Koh Tan, Koh Madsum and fishing in one day. The price covers 1 to 10 people, and the boat takes up to 20.
The location helps. Hilux is moored on the west side of Koh Samui, close to Koh Tan and Koh Madsum, so you spend less of the day getting there and more of it on the water where the dolphins are looked for.
The child pricing makes it especially good for families. Children up to 10 travel free of charge, children aged 11 to 14 cost ฿800, and each extra adult from the 11th guest costs ฿1,500. A family group with grandparents and kids fits comfortably on a 15 m boat.
On board there are soft drinks, water, fruits, a BBQ grill, snorkelling equipment and life jackets, with fishing equipment on request. A guide comes along too, which is useful when the crew is scanning the water and someone needs to explain what you are looking at.
Hilux has other programs in the same area if you want a shorter day: Koh Tan and Koh Madsum with fishing in 4 hours for ฿32,000, or with Koh Rap in 6 hours for ฿49,000. These do not list dolphins, though. If dolphins are the point, the 8-hour program is the one to book. You can see all the routes on the Hilux motor yacht page.
Lisa: the premium dolphin day
Lisa runs a full 8-hour day from 10:30 to 18:30 with dolphin watching and Koh Tan for ฿145,000, based on 10 people. It is the choice for a group that wants a proper yacht, lunch on board and drinks included.
Lisa is a 43-foot Fairline with two double cabins and room for 13 guests. Each extra person beyond 10 costs ฿3,000. Hotel transfer and lunch are included on the full-day trips, along with soft drinks, fruits, snacks and either 2 bottles of wine or 24 cans of beer.
On board you also get a paddle board, a dinghy, fishing rods, snorkelling equipment, a Bluetooth speaker and English-speaking staff. It is a much more polished day than Hilux, and the price reflects that.
Is it worth paying more for the dolphins? Not for the dolphins alone. The chance of a sighting is not higher on a more expensive boat. What you pay for is the yacht, the service and the comfort. If that is what your group wants anyway, the dolphin day is a lovely way to use it.
Note that Lisa's dolphin route is with Koh Tan. If you also want Pig Island, Lisa has other full days, such as Pig Island, Koh Tan and Koh Rap for ฿135,000, but that program does not list dolphins. The details are on the Lisa motor yacht page.
How likely are you to see dolphins, and when is the best time?
Your chances are reasonable on a calm day and drop a lot when the sea is choppy. Flat water is the single biggest factor, because a dorsal fin is easy to spot on a glassy sea and almost invisible among whitecaps.
Mornings usually bring the calmest water, before the afternoon breeze picks up. The light is softer too, with less glare on the surface. That is a big part of why I like the earlier start on Hilux, though any time of day can work when the sea is flat.
The season matters as well. From about November to January, the north-east monsoon can make the Gulf of Thailand rough, and trips may change route or be postponed. On those days dolphin spotting becomes much harder even if the boat goes out. The calmer months give you the best odds.
A few things improve your chances on the day:
- Keep everyone scanning in different directions, and watch for birds diving: they often mean fish, and fish can mean dolphins.
- Wear polarised sunglasses, which cut the glare and make fins easier to see.
- Stay patient and quiet when the crew slows down: dolphins surface, dive and surface again some distance away.
- Have the camera ready but do not spend the whole time behind the screen. The best sightings are often over in a minute.
- Trust the crew's judgement about where to look. They know which areas have been good recently.
And be ready for a blank. Some days the dolphins are simply somewhere else. If that happens, go for the swim, the beach and the BBQ, and enjoy the islands.
How should you behave around dolphins?
Let the dolphins set the distance. A good crew slows down, keeps a steady course and never drives straight at the animals, and guests should stay calm, quiet and in the boat.
Never chase, feed or try to touch wild dolphins. Chasing stresses them and can split up a group with young ones. Feeding changes how they behave and is bad for their health. Swimming towards them almost always makes them leave.
Here is the etiquette I ask every group to follow:
- Stay seated or still when the dolphins are close, and keep your voice down.
- Do not jump in the water to swim with them, even if they come near the boat.
- Do not throw food, ice or anything else into the water.
- Ask the crew not to circle or cut in front of the dolphins if you feel the boat is getting too close.
- Give them time and let them leave when they want to. A short, calm sighting is better than a long, stressful one.
On a private boat you have more control over this than on a crowded day tour, because you can tell the crew what you are comfortable with. Use that. A respectful sighting is the one you will remember with a good feeling.
Is a dolphin trip worth it, or should you just do Koh Tan and Pig Island?
If you are happy with a full day around Koh Tan and want a real chance of dolphins, the Hilux dolphin program is worth it. If you mainly want beaches, snorkelling and Pig Island, a simpler boat to Koh Tan and Koh Madsum is cheaper and just as enjoyable.
For a straight island day, Pearl runs 8 hours to Koh Tan and Koh Madsum for ฿38,000 for up to 6 guests, with hotel transfer included. The long-tail from Thong Krut Pier is the budget option, from ฿3,000 for 1 to 2 people for a half day at Koh Madsum and Koh Tan. These boats do not list a dolphin program, so do not book them expecting one.
For a fuller picture of the islands themselves, read the guide to Koh Tan and Koh Madsum and the earlier article on the Pig Island boat trip. Remember the entrance fee of ฿50 per person for each of Koh Madsum and Koh Rap, which is not part of any boat price.
One more note on timing. Hilux also runs Ang Thong National Marine Park, but the park is usually closed every year from 1 November to 15 December, so no Ang Thong trips run then. In those weeks, the southern islands and the dolphin program are a good alternative, sea permitting.
How to book a dolphin trip from Koh Samui
Choose Hilux or Lisa, pick your date and send a free, non-binding request from the boat page or on WhatsApp. A manager checks that the boat is free and confirms the final price for your group before anything is paid.
In the request, give the date, the number of adults and the ages of any children, since the Hilux child prices depend on age. Say that dolphins are the priority, so the crew can plan the day around the calmest water.
If neither boat is free on your date, or the group is a different size, it is worth comparing the other motor yachts on Koh Samui for a Koh Tan day. Just remember that only Hilux and Lisa list a dolphin program, so on any other boat a sighting is pure luck.
A sensible plan for most groups looks like this: choose the 8-hour Hilux dolphin day if you are a family or a group of friends on a normal budget, choose Lisa if you want lunch, wine and a premium yacht, and choose Pearl or a long-tail if the islands are all you need. Whatever you pick, go with the idea that the sea decides what you see.
Bring swimwear, reef-safe sunscreen, a hat, polarised sunglasses, a dry bag for your phone and cash for the island fees. And keep a spare day in your plans if you travel between November and January, when the sea sometimes makes the decision for you.
Questions and answers
Are dolphin sightings guaranteed on these trips?
No. The dolphins are wild and move freely, so no boat can promise them. The programs combine the search with Koh Tan and other island stops, so the day is still full even if the dolphins do not appear.
Can we swim with the dolphins?
It is better not to. Swimming towards dolphins usually makes them leave and can stress them, especially groups with young ones. Watch from the boat and swim at the island stops instead.
Is the dolphin trip good for children?
Yes, especially on Hilux, where children up to 10 travel free and children aged 11 to 14 cost ฿800. Life jackets and snorkelling equipment are on board. Bring hats and plenty of sun protection, since spotting dolphins means a lot of time on an open deck.
Do we get a refund if we see no dolphins?
The boat price is for the charter and the program, not for a sighting, because nobody can control wild animals. If the sea is too rough to go out, the manager will discuss changing the date. Ask about the conditions when you book.
Which side of Koh Samui do the dolphin trips leave from?
Hilux is moored on the west side of Koh Samui, close to Koh Tan and Koh Madsum. Lisa includes hotel transfer, so the crew arranges how you get to the boat.
Can we fish on the dolphin trip?
On Hilux, the dolphin program includes fishing, with fishing equipment on request. Lisa has fishing rods on board, so ask the crew if you want to try when the boat is at anchor.
Is lunch included on the dolphin trip?
Lisa includes lunch on its full-day trips. Hilux includes soft drinks, water, fruits and a BBQ grill, but lunch is not in its list, so ask the manager what to arrange or bring.
Ready to choose your boat?
Every boat page shows the routes, prices and what is included. The booking request is free: a manager checks the boat is free on your date and confirms the price.
Updated 6 November 2026. Prices can change: the boat page always shows the current price.
