- A half day of about 4 hours comfortably covers Koh Tan and Koh Madsum (Pig Island) in the south or the small islands off the north-east coast, but not Ang Thong or Koh Tao.
- Half-day prices per boat start at ฿3,000 on the Long-tail Boat for 1-2 people and ฿21,000 on the Vickey catamaran for up to 6 guests.
- Ang Thong National Marine Park and Koh Tao are full-day trips only, for example ฿39,000 and ฿41,000 on the Pearl speedboat for up to 6 guests.
- Ang Thong is usually closed from 1 November to 15 December, so full days there are not possible in that window.
- Families with small children, first-timers and anyone worried about seasickness usually get more from a morning half day than from 8 hours at sea.
It is your third evening on Koh Samui, the sunburn from the beach is fading, and someone at dinner says, "Let's get a boat." The next question is always the same: a half day boat trip on Koh Samui, or the whole day out at sea? I have watched hundreds of groups make that choice, and the right answer depends less on budget than on where you want to go and who is coming with you.
This guide compares the two honestly, with real per-boat prices, the routes that fit each format and the situations where the long day is simply too much.
How far can a half day boat trip on Koh Samui actually go?
A half day of about 4 hours gets you to the islands closest to Samui and back, with real time in the water. In practice that means two areas: Koh Tan and Koh Madsum (the island known as Pig Island) off the south coast, or the small islands and bays off the north-east corner, such as Koh Som, Koh Mad Lang and Thongson Bay.
The southern pair is the classic short trip. Koh Tan has coral off its sandy beaches, which makes it a good snorkelling stop, and Koh Madsum has the beach with the pigs that most people have seen on social media. You can read more about both on the Koh Tan and Koh Madsum charter page. On a 4-hour trip you get these two islands, or a third small stop like Koh Rap, but nothing further.
The north-east option suits the catamarans that offer it, Vickey and Scarlet. These are short hops, so most of the half day is spent at anchor swimming, paddling and lying on the nets rather than motoring.
What does not fit into a half day: Ang Thong National Marine Park, Koh Tao and a proper exploration of Koh Phangan. There is no 4-hour Ang Thong or Koh Tao program on any boat in the list, and that is the right decision. Those crossings would eat the whole half day.
What does a half day cost compared with a full day?
Prices on Koh Samui are for the whole boat, not per person, and each boat has a base group size. A half day on the same boat usually costs a good deal less than its 8-hour version, but not half, because the boat, crew and fuel to reach the islands are needed either way.
Here is how the boats that offer both formats compare. Each price is for the boat and the base group shown on its page.
| Boat | Half day (about 4 hours) | Longer day | Price covers |
|---|---|---|---|
| Long-tail Boat | ฿3,000 (1-2 people), Koh Tan and Koh Madsum | 4 hours only, ฿5,000 (1-2 people) with Koh Rap | Price by group size, up to 10 |
| Luxury Long-tail Boat | ฿6,000 (1-2 people) | 4 hours only, ฿7,000 (1-2 people) with Koh Rap | Price by group size, up to 10 |
| Vickey catamaran | ฿21,000 morning, ฿22,000 afternoon with sunset | ฿35,000 Koh Phangan | Up to 6 guests |
| Victoria catamaran | ฿25,000 morning or afternoon | ฿35,000 (6 hours), ฿39,900 (8 hours) | Up to 10 guests |
| Nina catamaran | ฿29,000 morning, ฿31,000 afternoon | ฿38,000 (6 hours), ฿43,000 (8 hours) | Up to 8 guests |
| Scarlet catamaran | ฿32,900 morning, ฿34,900 afternoon | ฿47,900 (6 hours), ฿52,000 (8 hours) Koh Phangan | Up to 8 guests |
| Blue Coco catamaran | ฿36,000 morning, ฿41,000 afternoon | ฿52,000 Koh Tan and Koh Madsum, ฿72,000 Ang Thong | Up to 10 guests |
| Coco Paradise catamaran | ฿45,000 morning, ฿50,000 afternoon | ฿65,000 Koh Tan and Koh Madsum, ฿85,000 Ang Thong | Up to 10 guests |
| Serenity catamaran | ฿60,000 morning or afternoon | ฿100,000 Koh Tan or Koh Phangan, ฿130,000 Ang Thong | Up to 25 guests |
Two things in this table are worth noticing. First, the afternoon half day is often a little more expensive than the morning one, because it runs into the sunset hours. Second, several catamarans have a 6-hour option in between, which is a smart compromise that many people miss.
Keep the extras in mind too. Island entrance fees are paid separately: ฿50 per person for Koh Madsum and the same for Koh Rap. The long-tails leave from Thong Krut Pier on the south coast, and the transfer there is not included; a round trip can be added for ฿1,500.
Morning or afternoon: which half day is better?
The morning half day is the better choice for snorkelling and calm water; the afternoon is the better choice for light, photos and a sunset on the way home. Both are good, they just give you different days.
In the morning the sea in the Gulf is often at its flattest, the water is clearer before the wind picks up and you reach the beaches before the day-trip crowd. You are back on land by lunchtime, which frees the afternoon for the pool, a massage or a nap. On the long-tails the morning slot runs from 9 am to 1 pm; on Vickey and Scarlet it is 09:00-13:00, and Blue Coco starts at 08:30.
The afternoon has a softer, warmer light, and the colours of the water and the islands look better in photos. The long-tail afternoon slot runs 2 pm to 6 pm, and in good weather you watch the sunset from the sea on the way back. Vickey sells its afternoon program as a half day with sunset, from 14:00 to 18:30.
The downsides are honest ones. Afternoon wind can add some chop, the midday sun is at its hardest when you board, and on a hazy day there may be no dramatic sunset at all. If snorkelling is the main goal, book the morning; if the evening view matters more, book the afternoon.
Is a half day better with kids?
For most families with young children, yes. Four hours is long enough for swimming, the pigs on Koh Madsum and a snack on deck, and short enough that nobody melts down before the boat is back at the pier.
Heat is the real issue on a long day. Even with shade on deck, eight hours of tropical sun, salt water and engine noise is tiring for small children and for many adults. The morning half day avoids the hottest hours and gets everyone home in time for a proper lunch and a sleep.
Catamarans are the easiest family choice for a short day because the two hulls keep the boat steady at anchor and there is plenty of room to move around. Nina and Victoria both run 4-hour trips to Pig Island and Koh Tan, and Nina adds a water slide on programs of 4 hours or more, depending on the program. Life jackets are included on these boats.
A full day can still work with older kids who swim well and love the water, especially on a spacious catamaran. Just be realistic: the long trips to Ang Thong and Koh Tao include longer crossings, and that is where children get bored or seasick. Families with small children will get a separate, detailed guide soon.
When is a full day worth it?
A full day is worth it when the place you want to see is far away, and Ang Thong National Marine Park and Koh Tao are the two clear cases. They are only sold as full days, and they are the places people remember years later.
Ang Thong is a protected archipelago of 42 islands with limestone cliffs, viewpoints, lagoons and snorkelling. You need the whole day to reach it, explore a few islands and come back without rushing. The park entrance fee is extra: ฿300 per adult and ฿150 per child. The details are on the Ang Thong charter page.
Koh Tao and Koh Nang Yuan are known for clear water and some of the best snorkelling in the Gulf of Thailand. A fast speedboat makes this a realistic day trip. Koh Nang Yuan charges ฿250 per adult and ฿125 per child, paid separately. See the Koh Tao and Koh Nang Yuan page for what the day includes.
For these two routes I usually point people to the Pearl speedboat, which is the most booked boat on the list for good reason. Pearl runs Ang Thong for ฿39,000 and Koh Tao with Koh Nang Yuan for ฿41,000 for up to 6 guests, with hotel transfer included. Ruby 38 is a comfortable alternative for up to 8 guests, and for bigger groups who prefer more deck space, Blue Coco does a full Ang Thong day for ฿72,000.
Here are good matches for a full day, depending on your group:
A full day also makes sense for Koh Phangan, if you want to anchor in its quieter bays rather than just pass by. Vickey goes there for ฿35,000 and Scarlet for ฿52,000 for 8 hours, with a Thai lunch served on the 6 and 8-hour Scarlet trips.
When is a full day not worth it?
A full day is not worth it when you are only going to Koh Tan and Koh Madsum and nobody in the group is a serious swimmer or snorkeller. Those islands are close, and a long day there often turns into several hours of waiting at anchor.
I see this every season. A group books 8 hours to Pig Island because it feels like better value, then by mid-afternoon everyone is sunburnt, the snacks are gone and people start asking the crew how long until the pier. The same trip in 4 hours would have felt better.
A few other situations where I would book the half day instead:
- Someone in the group gets seasick easily. Less time at sea is the simplest fix.
- You are travelling in the north-east monsoon season, roughly November to January, when the sea can be rough and routes may change or be postponed. A short trip close to shore is easier to reschedule.
- It is your first time on a private boat and you are not sure you will enjoy a whole day on the water.
- You have a dinner booking, a spa appointment or a flight the same day.
- You are with grandparents or small children who need shade, toilets and rest more than a long itinerary.
The 6-hour catamaran trips are the underrated middle ground. Victoria at ฿35,000 and Nina at ฿38,000 give you a relaxed day at Pig Island and Koh Tan without the late-afternoon fatigue of 8 hours.
Can you combine a half day boat trip with a beach afternoon?
Yes, and for many people this is the best day of the holiday: a morning at sea, lunch near the beach, and an afternoon on the sand or by the pool. It gives you the island-hopping highlight without spending the whole day on the boat.
The long-tails are the easiest way to do it. They leave Thong Krut Pier in the south at 9 am and are back by 1 pm, and the south coast has quiet beaches and simple seafood restaurants close by. If you are staying in the north, book the transfer so you do not have to arrange a taxi there and back yourself. More about this style of trip is on the long-tail boat page.
The difference between the two long-tails is simple. The standard Long-tail Boat comes with the captain, life jackets, snorkelling equipment and insurance. The Luxury Long-tail Boat adds cold drinks and fresh fruit, and costs ฿6,000 for 1-2 people instead of ฿3,000.
On the catamarans, the morning half day on Vickey (09:00-13:00) or Scarlet (09:00-13:00) works the same way. You can bring your own snacks, food and drinks on these boats free of charge, so a light picnic on board and a late lunch on land is a nice rhythm.
For a short morning out, these boats are a good fit:
How do you decide and book?
Start with the destination, then the group, then the hours. If the answer to "where" is Ang Thong or Koh Tao, it is a full day and a fast boat. If it is Pig Island and Koh Tan, a half day or a 6-hour trip is usually enough.
A quick checklist before you send a request:
- Choose the route first: Koh Tan and Koh Madsum, the north-east islands, Koh Phangan, Ang Thong or Koh Tao.
- Count your group, including children, and check the base number the boat price covers.
- Pick morning or afternoon on a half day: morning for snorkelling, afternoon for light and sunset.
- Check what is not included: island entrance fees, lunch, and the pier transfer on the long-tails.
- Keep a spare day in your plans in case the weather moves the trip.
Book the boat, not just the route: a stable catamaran for a slow family day, a speedboat for distance. You can compare all the catamarans on the catamaran charter page, then send a free request from the boat page or on WhatsApp, and a manager confirms the date and the final price for your group.
Questions and answers
How long is a half day boat trip from Koh Samui?
Most half days last about 4 hours. Typical slots are 09:00-13:00 in the morning and 14:00-18:30 or 14:30-18:30 in the afternoon, depending on the boat. Long-tails from Thong Krut Pier run 9 am to 1 pm or 2 pm to 6 pm.
Can I visit Ang Thong Marine Park on a half day?
No. Ang Thong is only offered as a full day, because the crossing and the time inside the park need the whole day. Remember that the park is usually closed from 1 November to 15 December.
Is the boat price per person?
No, prices are for the whole boat with captain and crew for your group. Each boat has a base group size, for example up to 6 guests on Vickey or up to 10 on Blue Coco, and extra guests cost a fixed amount each.
Are island entrance fees included in a half day trip?
Usually not. Koh Madsum and Koh Rap each charge ฿50 per person, Koh Nang Yuan ฿250 per adult and Ang Thong ฿300 per adult. Bring cash for these on the day.
What happens if the weather is bad on my booking date?
The crew may change the route or the trip may be postponed when the sea is rough, which is more likely from about November to January. On the long-tails there is no cancellation fee when extreme weather such as heavy rain or strong wind stops the trip.
Is a sunset cruise a good alternative to a half day?
It is shorter and more relaxed. Nina and Victoria both run 2.5-hour sunset cruises to Koh Tan, for ฿22,000 and ฿21,000. It is a good choice for couples, but you get less swimming and snorkelling time than on a half day.
Can we bring food and drinks on board?
On many catamarans, including Vickey, Nina, Victoria, Scarlet and Blue Coco, you can bring your own snacks, food and drinks free of charge, and glasses and dishes are on board. Check the boat page for the boat you choose.
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 4 November 2026. Prices can change: the boat page always shows the current price.
