Sailing Thailand’s Andaman Sea: Phuket & the Similans

Sailing in Thailand’s Andaman Sea (Phuket & the Similans): routes, conditions and practicalities

Thailand’s Andaman coast delivers a rare blend of easy line-of-sight cruising, dependable winter trade winds and showpiece anchorages under sheer limestone towers. From the marina hub of Phuket, sailors can fan out into the glassy labyrinth of Phang Nga Bay, push south to the Phi Phi islands and Krabi’s sculpted headlands, or make a bluewater hop northwest to the Similan Islands when the national park opens. Waters are warm year-round, passages are short for most routes, and support ashore is unusually strong for Southeast Asia.

This guide sets out the sailing areas, seasonal winds, where to berth and anchor, and how to charter (and what paperwork you’ll need) so you can plan with confidence.

Quick links

• Why Sail in Thailand’s Andaman Sea: Phuket & the Similans?
• Itineraries
• When to go
• Wind and weather
• Getting there
• Chartering
• Licences and formalities
• Anchorages and marinas
• FAQs
• References

Why Sail in Thailand’s Andaman Sea: Phuket & the Similans?

The Andaman Sea around Phuket rewards curiosity. East of the island, Phang Nga Bay unfolds as a protected inland sea peppered with karst pinnacles, mangroves and hidden hongs. Navigation is straightforward in good light, the water is predominantly flat in the northeast monsoon, and there are numerous all-weather haunts that let newer crews build miles without strain.

Push a little farther and the scenery changes gear. South and east, Krabi’s Railay headlands and the Phi Phi islands present dramatic anchorages with good holding, clear water and lively shoreside options. To the southwest, the twin Racha islands offer reef snorkelling and a starry, rural feel within a single day’s sail of base.

In season, the Similan Islands add a more offshore dimension. Forty to sixty nautical miles from the mainland, these granite isles offer oceanic water clarity, mooring-buoy protection and some of the region’s finest diving. The sail out is a satisfying stretch for competent crews, balanced by well-marked marinas and reliable services back in Phuket.

 

Itineraries

Below are suggested itineraries that balance short, line-of-sight passages with standout anchorages. Adjust daily runs to suit tide, forecast and crew energy, and always arrive in good light to assess fringing reefs and moorings.

7-day Phuket, Phang Nga & Phi Phi loop (NE monsoon focus)

An easy-going week designed for the northeast monsoon. Expect flat water in Phang Nga Bay, short hops between limestone outcrops and a couple of slightly longer legs to the Phi Phi and Racha islands. Ideal for mixed-experience crews and families who want variety without long days at sea.

Day 1: Ao Po Grand Marina to Ko Phanak and Ko Roi (10–15 nm)

Ease into Phang Nga Bay with a short hop. Explore Ko Phanak’s cave systems and hong at slack water, then move to Ko Roi for a quiet, protected overnight in mud and sand. Bring a headtorch and time dinghy explorations to the tide height.

Day 2: Ko Roi to Khao Phing Kan (James Bond) and Koh Panyee, then to Railay (25–30 nm)

Visit the iconic needle rock off Khao Phing Kan early to beat day boats, pause for lunch at Koh Panyee, then reach across Ao Phang Nga to Krabi for a sunset hook under Railay’s cliffs. Allow a margin for photo stops and day-boat wakes.

Day 3: Railay to Phi Phi Don (15–18 nm)

A relaxed reach past Ao Nang to Tonsai Bay or a calmer anchorage on the north side of Phi Phi Don. Take a mooring where available and avoid coral when dropping the hook; arrive early for the best spots.

Day 4: Phi Phi Le and Ko Mai Ton to Ko Racha Yai (30–35 nm)

Early swim at Maya Bay (check seasonal restrictions), then a lunch stop off Ko Mai Ton before a longer leg to Racha Yai’s clear-water bays with sand patches and laid moorings. Keep good offing from reefs on approach in bright light.

Day 5: Ko Racha Yai to Nai Harn (12–15 nm)

Short hop to Phuket’s southwest corner. Nai Harn is well-loved in the NE monsoon with good holding in sand; watch for afternoon sea-breeze gusts funnelling off the hills and give swimmers a wide berth.

Day 6: Nai Harn to Koh Khai Nok and Koh Yao Noi (25–30 nm)

Round Phuket’s south and back into shelter. Clear water and a busy day-boat scene at Khai Nok, then a peaceful evening on the east side of Koh Yao Noi. Thread fish traps carefully and avoid shallow sandbars on low tide.

Day 7: Koh Yao Noi to Ao Po Grand Marina (10–15 nm)

Weave back through the islets with the tide. Re-fuel and handover at Ao Po. Aim for a rising tide for easier berth approaches and to cushion any shoal spots in the channels.

Daily distances are modest, making it easy to linger at favourite spots or to build in longer lunch stops for swimming, kayaking and hong exploration.

10-day West Coast & Similans with a Phang Nga return (seasonal)

A more ambitious plan for the Similan National Park open season, blending Phuket’s fair-weather west coast, an offshore return to the Similans on park moorings, then a scenic run back via Krabi, Phi Phi and the Rachas. Best for confident skippers comfortable with 50–60 nm days and early starts.

Day 1: Yacht Haven to Bang Tao Bay (18–20 nm)

Depart the north of Phuket and work down the west coast. Bang Tao offers a fair-weather roadstead in the NE monsoon with open-swell awareness; anchor in sand and allow for gentle roll.

Day 2: Bang Tao to Tab Lamu (35–40 nm)

A coastal leg to the mainland staging harbour for the Similans. Anchor off the river mouth or arrange a berth if available. Expect coastal fishing gear and give trawlers a wide berth.

Day 3: Tab Lamu to Similan Island #8 (Ko Similan) (55–60 nm)

Bluewater day to the national park. Pick up a park mooring; no anchoring on coral. Check in with rangers on arrival and confirm permitted overnight zones.

Day 4: Similan Island #4 (Ko Miang) and surrounding moorings (10–15 nm local)

Short relocations between permitted moorings for snorkelling and beach time. Observe park rules and overnighting zones, and keep engines in neutral near divers.

Day 5: Similans to Tab Lamu (55–60 nm)

Return to the mainland with an early start. Re-provision and reset for coastal cruising. Keep an eye on afternoon sea breezes freshening on the nose.

Day 6: Tab Lamu to Ao Nang/Railay (40–45 nm)

Long coastal reach around the headland into Krabi. Anchor under Railay’s cliffs if conditions are settled; the scenery repays the extra miles.

Day 7: Railay to Phi Phi Don (15–18 nm)

Hop across to Phi Phi for moorings, water clarity and a lively scene ashore. If it’s rolly at Tonsai, shift to the north or east of Phi Phi Don in settled weather.

Day 8: Phi Phi to Ko Racha Noi (35–40 nm)

A satisfying open-water leg to the quieter of the Racha pair. Anchor in sand with care for fringing reef and ensure good light for entry and exit.

Day 9: Ko Racha Noi to Chalong Bay (20–22 nm)

Round Phuket’s southern tip into its principal yachting anchorage. Expect traffic and swinging room constraints near the pier; set an anchor light early.

Day 10: Chalong to Yacht Haven via Phang Nga channels (35–40 nm)

Tide-aware pilotage through the east-coast shallows and past Koh Yao. Finish at Yacht Haven for fuel and handover, allowing time for a final washdown.

This route mixes one or two longer offshore pushes with plenty of recovery days in sheltered water, giving crews time to enjoy beaches, hikes and snorkelling between passages.

When to go

The northeast monsoon (roughly November to April) is the prime season: drier air, friendlier seas and generally reliable E–NE winds. December to February offer the most settled conditions; March and April are hotter with lighter gradient winds, but regular sea breezes still drive pleasant afternoon sailing. The southwest monsoon (May to October) brings more frequent rain, stronger squalls and a west-facing swell that makes Phuket’s outer west-coast anchorages uncomfortable or untenable. Many crews continue to cruise the sheltered east side of Phuket and Phang Nga Bay through this period. The Similan Islands national park normally opens mid-October to mid-May and closes for the wet season; daily visitor caps and occasional site-specific closures apply. Sea temperatures sit near 27–30°C year-round.

Public holidays and peak tourism weeks (Christmas/New Year and Chinese New Year) see busier moorings at Phi Phi and popular Krabi bays. Book ahead for marina berths and simulate earlier starts to arrive before day boats. Water clarity is typically best mid-season, especially around the Rachas and Similans.

Wind and weather

Northeast monsoon (Nov–Apr)

Expect 8–18 knots from NE–E with afternoon sea breezes veering on-shore along Phuket’s west coast. Seas are typically slight to moderate outside, and flat in Phang Nga Bay. Squalls are less common but can still arrive with convective build-ups; reef early and secure loose gear when clouds tower.

Shoulder season (Mar–Apr)

Hot and hazy at times, with lighter gradient winds. Local sea breezes (10–15 knots) are dependable enough for relaxed day-sailing, and nights remain calm in most anchorages. Hydration and sun protection matter—shade, wind scoops and early swims help keep the crew comfortable.

Southwest monsoon (May–Oct)

Prevailing SW–W 12–25 knots with embedded squalls and thunderstorms. A persistent swell affects west-facing bays; the east side of Phuket, Phang Nga and parts of Krabi give good lee. Visibility can drop in heavy rain—avoid night entrances and use radar/AIS where fitted.

Tides and streams

Tides in greater Phuket are mixed semidiurnal with a spring range commonly 2–3 metres. Tidal streams are modest (generally under 2 knots) but accelerate in narrows and around headlands in Phang Nga and near the Koh Yao channels. Plan cave and hong visits close to slack water, and allow for cross-sets when lining up passes.

Storms and good practice

Lightning risk increases in the wet season; unplug sensitive electronics during nearby storms and avoid touching metal spars. Tropical cyclones are rare but heavy rain and gust fronts can occur—check daily forecasts, set plenty of scope and consider a second anchor in marginal holding.

Getting there

Phuket International Airport (HKT) has frequent regional and some long-haul links. Transfer times are short to the principal charter marinas on the island’s northeast: Yacht Haven (about 20–30 minutes), Ao Po Grand Marina (around 25–35 minutes), Royal Phuket Marina and Phuket Boat Lagoon (both 30–40 minutes). Krabi International Airport (KBV) is an alternative for crews joining in Ao Nang/Railay area, with a road transfer to Phuket marinas in 2.5–3.5 hours.

Provisioning is straightforward: large supermarkets and specialist stores near Boat Lagoon/Royal Phuket Marina and in Phuket Town offer delivery to most charter bases. Fuel, water and engineering support are excellent by regional standards. Chalong Bay is the primary small-boat hub on the south coast and remains the clearance point for private yachts, while charter handovers are usually conducted in marinas on the east side.

Local SIM cards (AIS, TrueMove, DTAC) provide good coastal coverage; ride-hailing apps and metered taxis work reliably for airport and supermarket runs. If arriving late, pre-arrange early boarding or a sleep-aboard so you can complete briefings in daylight.

Chartering

Phuket is Southeast Asia’s most established bareboat hub. Fleets span modern cruising monohulls and a strong bias toward catamarans, which suit warm weather, shallow anchorages and family crews. Major operators base at Ao Po Grand Marina, Yacht Haven, Royal Phuket Marina and Phuket Boat Lagoon. Skippered and crewed options are widely available for those who prefer a hands-off week or want to reach the Similans efficiently.

Typical charter patterns favour short hops in Phang Nga and Krabi, with 10-day bookings allowing a Similan excursion in season. National park fees are payable when visiting Similan/Surin, Phi Phi, Phang Nga Bay hongs and some Krabi sites; charter companies can advise current rates and may pre-arrange Similan permits during open months.

Practical tips

• Pre-order bulky provisions and drinking water; many bases deliver to the pontoon.
• Carry cash for moorings, park fees and small piers where cards are not accepted.
• Use mooring buoys where provided (Phi Phi, Similans) and avoid anchoring on coral.
• Expect security deposits or damage waivers in line with international norms.
• Many bases can arrange early boarding or late return for a fee—handy for awkward flight times.
• Ask about snorkel sets, fishing permits, paddleboards and child lifejackets when booking.

Most boats carry paper charts and plotters; bring your preferred nav apps and a headtorch for cave visits. A lightweight tarp or boom tent can be transformative for shade at anchor.

Licences and formalities

Skipper certification for bareboat

Most Phuket operators ask for an International Certificate of Competence (ICC) or equivalent (e.g., RYA Day Skipper Practical, ASA 104 Bareboat). A short sailing CV evidencing recent skippering and, ideally, coastal night experience is commonly requested. For catamarans, ASA 114 or demonstrable multihull time is helpful. A VHF/SRC operator’s endorsement is typically required. Thai law does not prescribe the ICC per se, but charter providers set the standard.

Crew documents

Passports should have at least six months’ validity, with visa exemptions or visas per nationality. Keep a crew list and passport copies onboard; the charter base usually files local notifications.

National parks

Similan and many Phi Phi/Phang Nga sites levy per-person daily fees plus a vessel fee. Similan entries may require advance booking and have strict daily quotas. Overnighting is restricted to designated moorings/areas; anchoring on coral is prohibited.

Private yachts clearing in

Ao Chalong’s Yacht Control Center handles Customs, Immigration and Harbour Department formalities. For bareboat charters staying within Thailand, the operator manages vessel papers—no inter-provincial clearance is needed.

Environmental conduct

Pump-out is limited—use shore facilities where possible. Separate waste and land it ashore, reduce plastics, and keep engines off near wildlife. Maintain respectful distances from whale sharks, mantas and turtles.

Regulations evolve; your charter company will brief you on current procedures and any park-specific restrictions before departure.

Anchorages and marinas

Marinas and haul-out (northeast Phuket)

Phuket’s marina cluster on the northeast coast offers all-tide access at the deep-water facilities and comprehensive shoreside support across the board. Approaches to the tidal basins require timing and care on neaps.

Marina	Access	Facilities and notes
Ao Po Grand Marina	Deep-water, all tides	Fuel dock, large charter presence, easy egress into Phang Nga Bay
Yacht Haven Marina	All tides, north Phuket	Berths for larger yachts, convenient for airport transfers
Royal Phuket Marina	Tidal creek access	Time arrival on a rising tide; strong services and chandlery
Phuket Boat Lagoon	Tidal creek access	Adjacent to Royal Phuket Marina; full-service yard and contractors

Book ahead in peak season and confirm fuel dock hours. For the creek marinas, request waypoints and depth guidance from your base and plan the transit in daylight on a rising tide.

Key anchorages by area

Phang Nga Bay

Ko Phanak (caves and hongs—time for slack), Ko Hong (Krabi) and Ko Roi offer protected nights in mud and sand. The east coasts of Koh Yao Noi/Yai provide numerous sand patches with lee in both monsoons; watch aquaculture stakes and fish traps.

Plan dinghy explorations with the tide to avoid strong flows through cave systems and narrow lagoons.

Krabi coast

Railay/Phra Nang deliver dramatic scenery in settled weather, with Ao Nang providing nearby services. Holding is generally good in sand, but expect longtail traffic and wakes at busy times.

In fresh westerlies these open bays can develop swell—have a fallback on the lee side of nearby islands.

Phi Phi Islands

Tonsai Bay has moorings and bustle and can be rolly. Quieter options lie on the north and east of Phi Phi Don in settled conditions. Maya Bay access is tightly managed and often daytime only.

Use park moorings where available, and always check for coral before lowering the anchor.

Racha Islands

Racha Yai’s western and northern bays provide clear water and reliable sand; pick up moorings where laid. Racha Noi is more exposed with fringing reef—good light is essential for eyeball navigation.

Water clarity is often excellent here; post a bow lookout when entering in the afternoon sun.

Phuket west coast (fair-weather, NE monsoon)

Nai Harn and Kata offer pleasant stops with sand holding. Expect open-roadstead swell if winds back westerly. During the SW monsoon many west-coast bays are untenable.

Give swimmers and surf zones generous room, and set a stern line if swell sets in.

Similan Islands (seasonal)

Mooring buoys at islands #4 and #8 and selected sites elsewhere. No anchoring on coral; overnighting only in designated zones. Rangers may direct movements between areas.

Arrive early in the day for the best choice of moorings and to complete park formalities without rush.

Navigation notes

Use recent charts and daylight for reef- and stake-strewn areas. Tidal sets can skew approaches at passes near Koh Yao and within Phang Nga’s narrows, and numerous unlit fishing craft and gear make night passages inadvisable.

• Post a bow lookout when sun is high and ahead; polarised sunglasses help read water colour.
• Rig a bridle on catamarans to reduce yaw at anchor in open roadsteads.
• Give dive boats, swimmers and snorkel areas wide clearance at popular reefs.

Conservative arrival times, generous scope and light-handed helming around coral will reward you with restful nights and pristine anchor spots.

FAQs

References

• https://www.cruiserswiki.org/wiki/Thailand%27s_Andaman_Sea_(Phuket_%26_the_Similans)
• https://www.tmd.go.th/en/
• https://www.thainationalparks.com/similan-islands-national-park
• https://www.aopograndmarina.com/
• https://www.pyhmarina.com/
• https://www.phuketboatlagoon.com/
• https://www.royalphuketmarina.com/
• https://www.marine.gov.in.th/
• https://www.tourismthailand.org/Destinations/Provinces/Phuket/350