The best water in Thailand, fifty-eight miles northwest into the open Andaman, on the only itinerary that has a legal season rather than a preferred one.
Closed for part of the year
Mu Ko Similan and Mu Ko Surin National Parks close by law from 16 May to 14 October. This is a legal closure, not a weather recommendation.
Not runnable in: May, June, July, August, September, October.
The Similans are the reason experienced divers come to Thailand rather than somewhere else. Nine granite islands well out into the Andaman Sea, far enough from the mainland to escape its run-off, with visibility that regularly gives thirty metres. The east sides are coral gardens on white sand and the west sides are stacked granite boulders full of swim-throughs.
This is not an extension of a bay itinerary. Fifty-eight miles each way is five to nine hours of passage depending on the hull, and the Surins are another forty miles beyond that. A yacht doing this route is at sea properly, and the yacht needs to be chosen for it.
The park closes from 16 May to 14 October every year. Any operator offering a Similan itinerary inside that window is offering something that cannot legally happen, and that is the fastest reliability test in this market.
Board at Yacht Haven at the top of Phuket, twenty minutes from the airport. Most crews take an evening anchorage on the northwest of the island and start the crossing before dawn, so that the first Similan mooring is picked up in daylight.
Landfall in the morning. Park moorings only, and no anchoring on coral anywhere in the park. The first day goes to the gentle eastern bays: white sand, shallow hard coral, and the first swim in water that is a different colour from anything in the bay.
Move to the western sites, where the granite boulders form arches and swim-throughs down to thirty metres. This is the day the divers came for. Snorkellers work the shallower boulder fields on the same moorings.
The passage north to Mu Ko Surin. The channel between the two main Surin islands is a natural harbour with park moorings and shelter from the northeast, and the Moken village sits on the water inside it.
A full day on the largest shallow reef in Thai waters. This is snorkelling rather than diving country: wide living reef flats you can work for hours in three to eight metres.
Return south with a second night on the Similan moorings, taking whichever sites the first pass missed.
The long leg home, usually started early so the yacht is alongside at Yacht Haven by mid-afternoon.
The value of doing this route on a yacht rather than on a day boat is control over the clock and the tide. Most of it comes down to these.
The Similans need a real passage, not a day trip: fifty-eight miles each way, which is five to nine hours depending on the hull. Any itinerary shorter than five days that lists the Similans is either using a fast motor yacht and giving you two hours ashore, or it is not actually going. Ask for the passage time in hours before you book.
A hundred miles each way puts the Surins out of reach of anything under about seven days, and most Similan itineraries stop short of them. If the Surins matter to you, say so at the enquiry stage: it changes the yacht, the length and the price, and it is not something to raise once the contract is signed.
No two operators run an identical itinerary. The variant is the useful part: a shorter version has dropped a destination, and it is almost always the furthest one.
Seven-night crewed, Similan and Surin, superyacht fleet
Similan-only five-night version, no Surin leg
Brokered superyacht charter, itinerary agreed with the captain
Brokered, seasonal availability November to April
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Sanlorenzo, 2018
A 37 metre Sanlorenzo from 2018 with five cabins and seven crew, one of the larger hulls that stays in Thai waters through the season rather than visiting for a few weeks.
from $14,900
per day
Ao Po Grand Marina
Not published, 2022
A 42 metre, six-cabin superyacht delivered in 2022 and listed for Thai charter, at the size where twelve guests is the legal ceiling rather than a design choice.
Rate on application
Ao Po Grand Marina
Sunreef Yachts
The luxury catamaran answer to a superyacht: twenty-four metres of beam-heavy platform with superyacht volume, shallow draught for the limestone anchorages, and the 24 metre length that puts it exactly on the Thai charter licence threshold.
from $90,000
per week
Ao Po Grand Marina
Source: Mu Ko Similan and Mu Ko Surin National Park schedules, operator itineraries. Checked 6 September 2026. Distances are planning figures and the coastlines on the chart are simplified. Neither is for navigation.