Similan Islands diving guide: sites, seasons, liveaboards and day trips
Phuket: Scuba diving day trip — King Cruiser & Shark Point
When are the Similan Islands open for diving?
The Similan Islands national park is open approximately November to May each year. The exact dates vary slightly but the park closes reliably in June and reopens in late October or November. Diving is not permitted outside these dates.
The Similan Islands sit in the Andaman Sea about 84 km north-west of Phuket, within Mu Ko Similan National Park. Among divers, they are considered one of the top ten dive destinations in the world and the finest accessible diving in Thailand. The granite boulder topography, 20–30 m visibility in peak season, exposure to open-ocean currents and density of large pelagic species make the Similans qualitatively different from the reef dives available around Phuket itself.
This guide covers the best dive sites, the seasonal opening and closure cycle, how to reach the islands from Phuket or Khao Lak, liveaboard versus day trip logistics, and what to do if the Similans are closed during your visit.
| Where | ~84km NW of Phuket, best reached via Khao Lak |
| Season | November–May only (closed June–October) |
| Cost | Day trip around 3,500–5,500 THB; liveaboard 15,000–35,000 THB |
| Time needed | Day trip: full day; liveaboard: 2–4 nights |
| Level | Open Water minimum, Advanced recommended for Christmas Point |
| Booking | Book liveaboards well ahead for December–February |
The Similan Islands: essential context
The Similan archipelago consists of eleven islands numbered south to north, though only some are accessible to visitors. The national park authority manages the islands strictly — anchoring in undesignated areas is prohibited, visitor numbers are capped at each island, and night diving is restricted to approved sites on liveaboard vessels.
Seasonal closure: The national park closes reliably in June each year and reopens in October or November. The exact dates are announced by the Department of National Parks annually. In recent years the closure has run approximately 15 May to 15 October, though this shifts slightly year to year. During the closure, no diving, snorkeling or island visits are permitted. This is a firm boundary, not a weather advisory. If you are visiting Phuket between June and October, the Similan Islands are not accessible at any price or via any operator.
Water temperatures at the Similans are 27–30°C from November to May. Visibility peaks in the dry season and is typically 20–30 m, dropping to 15–20 m as the season progresses toward April.
Getting to the Similan Islands from Phuket
The Similan Islands are not practically accessible as a conventional day trip from Phuket for most travellers. Here is the honest breakdown:
From Phuket directly: The boat journey from the northern tip of Phuket takes approximately 2–2.5 hours by speedboat in calm conditions. A “day trip from Phuket” therefore means departing by 04:30–05:00, arriving around 07:30, completing two or three dives, and returning to Phuket by 19:00–20:00. The transfer cost, fuel surcharge and exhaustion involved make this a poor-value option compared to the alternatives.
From Khao Lak (recommended for day trips): Khao Lak is a beach resort about 80 km north of Phuket on Route 4. The boat transfer from Khao Lak to the Similan Islands takes 60–90 minutes, making day trips genuinely viable. Day trips from Khao Lak depart around 08:00–08:30 and return by 17:00–18:00. The standard price is 3,500–5,500 THB (107–169 USD) including equipment, two to three dives and lunch.
Liveaboard from Khao Lak or Phuket (recommended for divers): A 2-night/3-day liveaboard vessel allows 10–14 dives including night dives, provides access to the full range of sites including more remote islands, and avoids the daily logistics of transfers. Liveaboards depart from Khao Lak (most commonly) and some from Phuket’s Ao Po Grand Marina or Chalong. Pricing ranges from 15,000–35,000 THB (460–1,075 USD) depending on vessel standard.
For travellers basing themselves in Phuket, a practical approach is to take a taxi or minibus to Khao Lak (approximately 1.5 hours) and join a day trip or overnight liveaboard from there.
Best dive sites at the Similan Islands
Christmas Point (Island 7 — Koh Similan)
Christmas Point is consistently cited as the most spectacular dive at the Similans. It consists of a series of massive granite boulders forming swimthroughs, arches and gullies that drop from the surface to around 30 m. Strong currents bring nutrient-rich water and attract large pelagic species — whale sharks, manta rays, grey reef sharks and schooling barracuda are all recorded here.
The topography is genuinely dramatic: the boulders are the size of houses, covered in sea fans, soft corals and encrusting sponges. Visibility regularly exceeds 25 m. The current at Christmas Point can be substantial, and this site is better suited for Advanced Open Water divers or those with experience in current diving.
Elephant Head Rock (Hin Pousar, Island 8)
Elephant Head Rock is named for its above-water profile and is arguably the most technically challenging dive at the Similans. A mass of submerged granite boulders creates a three-dimensional maze of tunnels, chimneys and swimthroughs at depths of 8–30 m. Multiple currents converge here, and navigation requires care.
The marine life density is extremely high: Napoleon wrasse, large groupers, moray eels, sea turtles and schools of fusiliers pack the structures. Leopard sharks rest in sandy patches between boulders. This is a dive for certified divers who are comfortable in moderate to strong current. Divemaster guidance is advisable for first visits.
East of Eden (Island 7 — Koh Similan, east side)
The east side of Koh Similan (Island 7) is a complete contrast to Christmas Point on the west: a sloping coral garden at 5–30 m with almost no current. Hard corals dominate — brain corals, table corals and staghorn formations — with very high fish diversity. Hawksbill turtles are frequently seen here.
East of Eden is suitable for all certification levels, including Open Water divers on their first Similan dives. It is often used as an orientation dive at the start of a liveaboard itinerary. Visibility is typically 15–25 m.
The Arch (Donald Duck Bay, Island 8)
A natural granite arch at around 20 m is the centrepiece of this site. The dive takes in the arch itself, surrounding boulder formations and a sandy bottom with scattered coral heads. Leopard sharks, blue-spotted stingrays and reef fish are the typical encounters. Mild current makes this a pleasant dive for most certified divers.
Island 8 also hosts the only designated camping area in the national park. Snorkeling at Donald Duck Bay is excellent, with coral starting in waist-deep water.
Beacon Reef (Island 9 — Koh Bangu)
Beacon Reef is a submerged reef on the east side of Island 9, notable for its hard coral coverage and gentle terrain at 5–18 m. It is one of the better beginner dives at the Similans, with minimal current and good fish diversity including clownfish, angelfish and large pufferfish. Reef sharks patrol the drop-off.
Richelieu Rock (Surin Islands, nearby)
Richelieu Rock is technically in the Surin Islands national park rather than the Similan Islands, but it is commonly included on liveaboard itineraries covering the Andaman’s northern dive zone. It is consistently rated among the top dive sites in Thailand for whale shark encounters (February–April) and has extraordinary invertebrate density — sea horses, ghost pipefish, and enormous density of nudibranchs.
Like the Similans, the Surin Islands and Richelieu Rock are closed June–October.
Liveaboard versus day trip: which to choose
Choose a liveaboard if: You are serious about diving, want maximum dives, want access to the full range of sites (including Richelieu Rock and remote southern islands), value night dives, and have at least 3–4 days available.
A 2-night/3-day liveaboard typically completes 10–14 dives including night dives at designated anchorages. The night diving at the Similans is excellent — cuttlefish, octopus, sleeping turtles and bioluminescent plankton are among the nocturnal encounters.
Vessel quality ranges considerably. Budget vessels (15,000–18,000 THB) have adequate but basic facilities. Mid-range (20,000–28,000 THB) offer en-suite cabins, better food and smaller groups. Premium vessels (30,000+ THB) include individual cabins, dedicated guides and equipment storage. Book liveaboards early for the December–February peak — vessels sell out weeks in advance.
Choose a day trip from Khao Lak if: You have one day to allocate, want to experience the Similans without a multi-day commitment, or are travelling with non-diving companions who can stay in Khao Lak. Day trips complete 2–3 dives at 1–2 sites and usually visit Island 4 (Koh Miang) or Island 8 (Koh Similan). They do not reach the more remote northern sites.
Diving near Phuket while the Similans are closed
The Similan Islands are closed for approximately five months each year (June–October). If you are visiting Phuket during this period, the main dive sites around Phuket remain accessible: King Cruiser wreck, Shark Point, Anemone Reef, and Racha Yai are all diveable for much of the monsoon season, weather permitting.
King Cruiser and Shark Point are among the best alternatives for certified divers wanting interesting diving without the Similan journey. The wreck at King Cruiser has good marine life year-round and the Shark Point pinnacles reliably deliver leopard shark encounters.
For a three-dive day covering both Phi Phi and Shark Point, the following option includes one of the best single-day itineraries available from Phuket:
For those who want to combine diving with snorkeling, or who are travelling with mixed groups:
See the full scuba diving Phuket guide for a complete breakdown of sites accessible from Phuket year-round.
Marine life highlights: what to expect at the Similans
The Similan Islands’ position in the Andaman Sea, combined with the open-ocean currents that sweep around the granite formations, creates conditions for a wider range of species than is typical of inshore reef diving.
Whale sharks: Sightings are recorded at Christmas Point, Richelieu Rock and several northern sites from February to April. They are not guaranteed — this is open-ocean wildlife, not a managed encounter — but the Similans are among the more reliable locations in Southeast Asia for whale shark encounters.
Manta rays: Predominantly seen at Christmas Point and Richelieu Rock from November to April. Cleaning stations at several sites attract both reef mantas and, occasionally, oceanic mantas.
Leopard sharks: Very reliable at Elephant Head Rock and Beacon Reef, resting on sandy patches in 5–18 m. The Similans have a notably large resident population.
Sea turtles: Hawksbill and green turtles are common throughout the archipelago. East of Eden on Island 7 is a particularly reliable spot.
Large pelagics: Schooling barracuda, large schools of big-eye trevally, grouper and Napoleon wrasse are common at the current-facing sites. The Similans are unusual in the region for the frequency of large-animal encounters.
Nudibranchs and invertebrates: The Similans have a high density of macro life that rewards slower, attentive divers. Ghost pipefish, frogfish and numerous nudibranch species appear at many sites.
Practical considerations for the Similan Islands
National park fees: A national park entry fee of 500 THB (approximately 15 USD) per person per day is charged at the island. This is sometimes included in liveaboard and day trip prices and sometimes charged separately — confirm before booking.
Accommodation on the islands: Camping is permitted at Island 4 (Koh Miang) with advance booking through the Department of National Parks. Facilities are basic. Most travellers either liveaboard or stay in Khao Lak.
Equipment: Most liveaboards provide full equipment rental. If you have prescription lenses, contact lens and goggle-compatible masks, or a specific regulator preference, consider bringing your own or confirming availability with the operator before departure.
Seasickness: The passage from Khao Lak to the Similans crosses open water and can be rough in transition season (October–November and April–May). Take preventive medication the night before and morning of departure if you are susceptible.
Dive insurance: DAN (Divers Alert Network) dive insurance is strongly recommended. The nearest hyperbaric chamber to the Similan Islands is in Phuket or Khao Lak. Emergency evacuation from the islands by boat takes 60–90 minutes before medical treatment can begin.
Planning your trip around the Similans
The Similan Islands fit naturally into a wider Phuket diving itinerary. A typical structure for a diving-focused 10-day trip during high season:
Days 1–3: Arrive Phuket, PADI Advanced Open Water or refresher dives at Racha Yai. See PADI courses in Phuket.
Days 4–6: 2-night Similan Islands liveaboard departing from Khao Lak.
Days 7–8: Return to Phuket, King Cruiser and Shark Point day trip.
Days 9–10: Phi Phi Islands day trip combining diving and sightseeing, or Phang Nga Bay sea canoe for non-diving activities.
For broader trip planning, best islands near Phuket and best day trips from Phuket cover how to structure time between water activities and island sightseeing.
Combining Similan diving with other Andaman sites
Divers with more than a week in the region sometimes extend the Similan liveaboard north to include Richelieu Rock and the Surin Islands, or south to add a day or two of Phuket-based diving at Racha Yai and King Cruiser before or after the liveaboard. This spreads the trip across different site types — granite boulder topography at the Similans, wreck and pinnacle diving near Phuket — rather than repeating similar conditions across the whole trip.
Choosing between liveaboard vessels
Liveaboard quality varies more than the headline price suggests. When comparing vessels, ask specifically about cabin type (shared dorm-style bunks versus private en-suite cabins), the diver-to-guide ratio on the boat, whether nitrox is available and at what extra cost, and how many dives per day are actually scheduled versus advertised. A budget vessel doing 4 dives a day with a 1:8 guide ratio is a different experience from a mid-range boat doing 3 dives a day at 1:4 — the latter usually delivers more per dive even with fewer total dives. Read reviews from the past six months specifically, since crew and vessel condition change over time.
What non-divers can do while you liveaboard
Liveaboards are not well suited to non-diving companions, since the entire itinerary is structured around dive schedules with limited beach or shore time. If you’re travelling with a non-diving partner or family member, the more practical structure is for them to stay in Khao Lak or Phuket while you join the liveaboard, then reunite for the rest of the trip. Khao Lak itself has a quieter, less built-up beach scene than central Phuket, which some non-diving companions actually prefer for a few restful days rather than joining the pace of a Phuket-based itinerary.
Similan liveaboard vs Phuket day-trip diving
| Similan liveaboard | Phuket day-trip diving | |
|---|---|---|
| Season | November–May only | Year-round |
| Commitment | 2–4 nights | Single day |
| Sites reached | Christmas Point, Elephant Head, Richelieu Rock | Racha Yai, King Cruiser, Shark Point |
| Visibility | Often 20–30m+ | 10–20m typically |
| Best if | Diving is the trip’s main purpose | Diving is one activity among several |
If you’re weighing the two rather than committing straight to a liveaboard, the Racha Island diving guide and full scuba diving Phuket guide cover the Phuket-based alternative in detail — both are diveable year-round, unlike the Similans.
Frequently asked questions about Similan Islands diving guide: sites, seasons, liveaboards and day trips
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