Similan Islands Day Trip
World-class diving and snorkeling — open November to May only
The Similan Islands are Thailand's crown jewel for diving and snorkeling. This archipelago of nine granite islands sits 70 km off the Andaman coast, in waters so clear you can see 30 meters to the bottom. Manta rays glide through cleaning stations, whale sharks cruise the open water, and the coral gardens are among the healthiest in Southeast Asia.
The islands are part of a national marine park and are open only from November to May. The seasonal closure allows the marine ecosystem to recover, and it shows — the biodiversity here is staggering. Whether you are a certified diver or a first-time snorkeler, the Similans deliver an underwater experience that is genuinely world-class.
The Similan Islands are open November to May ONLY. The park closes during monsoon season (June - October) for both safety and conservation. Plan your trip accordingly. Exact opening dates are announced annually by the Thai Department of National Parks.
Nov-May
Open Season
15-30m
Visibility
1.5 hrs
From Khao Lak
9
Islands
What to See & Do
Donald Duck Bay (Island 8)
The most photographed spot in the Similans — a massive boulder formation that resembles Donald Duck from certain angles. The bay has a pristine white sand beach and crystal-clear water. A short hike to the top of the rocks rewards you with a panoramic view of the surrounding islands. This is usually the first stop on day trips.
Snorkeling at Island 4 (Miang)
Island 4 has the best accessible snorkeling in the Similans. The coral reefs start just meters from the beach, with visibility reaching 20-30 meters on good days. Expect to see clownfish in their anemones, parrotfish, sea turtles, and colorful soft corals. The east side is more sheltered and better for beginners.
Princess Beach (Island 4)
A crescent of powder-white sand backed by tropical forest. This is where most day trippers eat lunch and relax between snorkeling sessions. The sand is so fine it squeaks underfoot — even more pronounced than Karon Beach. Beach chairs are not available; bring a towel and find shade under the trees.
Deep Sea Diving
The Similans are rated among the top 10 dive sites in the world. Visibility reaches 30 meters, currents bring nutrient-rich water supporting huge biodiversity, and the underwater granite boulders create dramatic swim-throughs. Highlights include manta ray cleaning stations, whale sharks (rare but possible January-April), and massive barrel sponges.
Honeymoon Bay (Island 7)
A sheltered bay with calm, crystal-clear water that is perfect for snorkeling. The coral gardens here are among the healthiest in the park, with brain corals, staghorn corals, and soft corals hosting hundreds of species of reef fish. Less crowded than Island 4 on most days.
Costs & Options
Includes: Hotel pickup from Phuket, van transfer to Khao Lak pier, speedboat, snorkeling gear, lunch, national park fee
Duration: 12-14 hours total (3 hours driving + 3 hours boat + 4-5 hours at islands)
The long travel time is the main drawback. You spend about 6 hours in transit and 5 hours at the islands.
Includes: Hotel pickup from Khao Lak, speedboat from Tab Lamu pier, snorkeling gear, lunch, national park fee
Duration: 8-9 hours total (30 min drive + 1.5 hours boat + 5 hours at islands)
The better option if you can spend a night in Khao Lak. Less travel time means more island time.
Includes: All meals, accommodation on boat, 8-14 dives, dive guide, equipment rental
Duration: 2-4 nights on a dive boat
The ultimate Similan experience. Multiple dives per day at the best sites, night dives, and early morning dives before day trippers arrive.
Marine Life You May See
Manta Rays
February - AprilCommon at cleaning stations
Whale Sharks
January - AprilRare but documented yearly
Sea Turtles
Year-round (when open)Common at snorkeling sites
Leopard Sharks
November - MayCommon on sandy bottoms
Clownfish
Year-round (when open)Abundant in anemones
Barracuda
Year-round (when open)Common in schools
Ghost Pipefish
December - MarchUncommon, macro diving
Reef Octopus
Year-round (when open)Common on night dives
Essential Tips
Stay in Khao Lak the Night Before
The Similan Islands are reached from Khao Lak, not Phuket. A day trip from Phuket adds 3 hours of driving each way. Spending a night in Khao Lak (hotels from 800 THB) means an easier morning, a shorter boat ride, and more time at the islands. This is our number one tip.
Bring Motion Sickness Meds
The 1.5-hour speedboat ride crosses open ocean and can be very rough, especially later in the season (April-May). Take Dramamine or a similar medication 30 minutes before departure. Even experienced boaters sometimes feel queasy on this crossing.
Book a Liveaboard for Diving
Serious divers should consider a 2-4 night liveaboard instead of a day trip. You get 8-14 dives including night dives and early morning dives before day trippers arrive. The chance of seeing manta rays and whale sharks increases dramatically with more dives. Book well in advance — liveaboards sell out months ahead.
Respect the Marine Park Rules
Do not touch coral, do not feed fish, do not collect shells, and do not use non-reef-safe sunscreen. The national park rangers enforce these rules strictly. The Similans' incredible marine health is the direct result of conservation — help keep it that way for future visitors.
Frequently Asked Questions
Get Your Free Travel Guide
PDF download + weekly travel tips
Join our community and get a comprehensive travel guide with maps, budgets, and insider tips delivered to your inbox.
Unsubscribe anytime. No spam, we promise.