It is almost impossible to overpay for the sea trip itself on Samui: the group prices here are narrow and close together. It is very easy, though, to come up short on everything that sits outside the price — park fees, island entries and the surcharge for a third person on a private boat.
Below is one week costed for two people from the operators' own prices, plus a walk through the places where the budget usually parts company with expectation. Every number comes from an operator card and is converted at a single rate.
- Three sea days for two — ฿16,100 ≈ $446, park fees already inside.
- The same week with a jet ski and a sunset yacht — ฿44,600 ≈ $1,235.
- The main surprise — park fees, which are almost never in the price.
In short
a week on the water for two runs from ฿16,100 ≈ $446 without a private boat and around ฿44,600 ≈ $1,235 with one. Park fees — ฿300 ≈ $8 at Ang Thong and ฿250 ≈ $7 at Koh Nang Yuan — are collected on the day.
What a week on the water costs for two
The full version of the week looks like this: the Ang Thong day at ฿5,200 ≈ $144 for two with the park fee, the Koh Tao day at ฿5,100 ≈ $141 with the Nang Yuan entry, and snorkelling from the dive boat at ฿5,800 ≈ $161.
On top come four hours on a jet ski — ฿6,500 ≈ $180 for the machine both of you ride — and a sunset sail at ฿22,000 ≈ $609 for the whole yacht. That is ฿44,600 ≈ $1,235 for five active days, and more than half of it is one private boat.
The cheap version: three sea days
Take out the private yacht and the jet ski and you are left with three full days at sea for ฿16,100 ≈ $446 for two. That is Ang Thong, Koh Tao and the dive-boat snorkelling day, with lunches, transfers and equipment inside the price.
Tip
leave at least one empty day between the three. They all start between 08:00 and 08:30 and finish in the evening, and most people take three in a row worse than they expect to.
Where the money leaks: park fees
Important
the national park fee is almost never included in the tour price. At Ang Thong it is ฿300 ≈ $8 per person, at Koh Nang Yuan ฿250 ≈ $7 per adult and ฿120 ≈ $3 per child, and they are collected on site on top of the booking you already paid.
There is one exception: on the Bluestars kayak day the marine park fee is already inside the ฿2,800 ≈ $78. So the straight comparison "฿2,800 against ฿2,300" is wrong: with the fee the speedboat day is ฿2,600 ≈ $72, and the gap shrinks two and a half times.
Transfers: what is already included
The hotel transfer is included on the speedboat days, on the kayak day and on the try dive off Koh Tao — there is no separate line to pay. That matters: the piers are spread across three different coasts of the island.
On the dive boat the free pickup covers Bophut, Chaweng, Bangrak and Choeng Mon; other areas the operator takes on request, and we confirm that when you book. Hence a simple rule: the north coast is cheaper for a week on the water than the south or the west.
The private boat: how the per-guest surcharge works
Private departures are sold by the hull, not per person, but with a guest threshold. On the sunset yacht ฿22,000 ≈ $609 includes two, each further guest is ฿2,500 ≈ $69, and six is the maximum aboard.
On the half day on the Thai yacht the threshold is higher: ฿25,900 ≈ $717 includes six, each further adult ฿1,200 ≈ $33 and child ฿800 ≈ $22. For a group of six that is ฿4,317 ≈ $120 a head, cheaper than the headline price for the hull suggests.
Children, the rate and the small stuff
The speedboat days have a reduced rate for children aged 3 to 9 under 130 cm, with under-3s free and a maximum of two per booking. On the kayak day children aged 5 to 11 pay ฿1,850 ≈ $51. We give you the exact child rate when you book.
The ferry to the island is ฿200 ≈ $6 per adult — ฿400 ≈ $11 for two, one way. At the airport the first 25 minutes of parking are free, then ฿20 ≈ $0.55 an hour, ฿100 ≈ $3 for 5–12 hours and ฿200 ≈ $6 for a full day; a lost ticket is ฿300 ≈ $8 plus the actual time.
The risks that actually cost money
The first risk is the calendar. Ang Thong Marine National Park is closed from 1 November to 15 December every year, and in those six weeks nobody runs a trip there. Planning your headline sea day into that window is pointless.
The second is weather. The rule is nearly universal: for safety the departure is rescheduled and you either move your date or take a refund. Which is why the big days go at the start of a trip, not on the last day before the flight.
