The South Siam IV liveaboard vessel serves as a stationary, full-service dive platform within the protected waters of the Similan and Surin national marine parks. Instead of following a rigid cruising itinerary, the boat remains on station, allowing you to tailor your trip length. With its uniquely flexible approach, you are transferred daily from the mainland by speedboat, joining the vessel ready to dive. This model provides exceptional freedom, perfect for scuba divers with limited time or those wishing to combine liveaboard diving with other Thai adventures.
The operations of the South Siam IV liveaboard are designed for simplicity. After the morning’s check-dive to orient you, the schedule typically features 3 daily dives at premier sites, including the iconic Richelieu Rock. The crew manages logistics efficiently, from tank handling to gear storage, leaving you to focus on the underwater world. This consistent base of operations eliminates packing and unpacking, offering the core liveaboard experience with adaptable scheduling.
The 30-metre vessel features multiple social areas, including a spacious shaded lounge for meals and a sun deck with loungers. An air-conditioned indoor saloon provides comfort for film evenings or quiet relaxation. All cabins benefit from individual climate control, private portholes, and functional amenities like personal reading lights. While accommodating a substantial number of guests, the layout of South Siam IV is conceived to offer personal space and respite between dive sessions.
The team behind the South Siam diving operation brings decades of regional expertise to your trip. As part of a well-established dive centre with a long history in the Similans, their knowledge of the local seas is extensive. This translates into informed site selection based on daily conditions and professional, safety-conscious guidance underwater. Their familiarity with these marine parks ensures a smooth, reliable service from the moment you step aboard until your return, building confidence through capability.
South Siam IV also warmly welcomes snorkellers and non-diving companions. They can join the daily speedboat transfers and enjoy the same access to spectacular shallow reefs, the vessel’s facilities, and optional beach landings on pristine island sands. It presents a straightforward solution for mixed groups, ensuring everyone can share in the adventure of this remarkable region from the same base.
For scuba divers seeking a concentrated dive schedule and community of a liveaboard without a fixed multi-night commitment, the South Siam IV liveaboard presents a great choice. Its fixed weekly schedule provides sustained access to world-class dive sites of Thailand. By combining a proven operational model with essential comforts and professional oversight, it stands as an effective option for diving the rich waters of the Similan Islands and Surin National Park.
There are 2 double bed cabins and 6 twin bed cabins on the main deck, and 2 more double bed cabins and 4 twin bed cabins on the lower deck of the South Siam IV liveaboard. There are 6 communal bathrooms.
All the cabins have:
- Individual control air-conditioning
- Seaview windows
- Shared bathrooms with toilet, shower and hand basin
- Reading lights
- Mains outlet - 220V
- Dressing table
- Bedding
No. of bathrooms / showers - 6 / 6 - hot water
Similan Islands, Koh Bon & Richelieu Rock
Trip highlights: whale sharks, manta rays, turtles
Diving environment: advanced divers, beginner divers, very popular, wall diving
Dive sites and activities: Similan Islands every day, except for Koh Bon on Tuesdays and Saturdays, Richelieu Rock on Wednesdays and Sundays
Day 1
From Thap Lamu pier in Khao Lak, a speedboat will ferry you across to the Similan Islands where the MV South Siam IV liveaboard is moored. After meeting the crew and enjoying a hot drink during the welcome briefing, you can settle into your cabin. Then it's time to sort out your dive kit, ready for an exciting day of 4 dives around the renowned sites of the Similan Islands.
Core Days
2 more fantastic days of diving await, with 2 morning dives each day, followed by an afternoon dive and then either a sunset or night dive just before dinner. Diving the Similan national park from a liveaboard gives you the chance to explore the sites and the incredible marine life that inhabits these waters. You can expect to see graceful manta rays, hawksbill turtles, giant trevally on the hunt, and colourful clownfish darting amongst anemones. Look out for lionfish, large Napoleon wrasse, and camouflaged octopuses hiding in the reef.
The area features breathtaking underwater topography and a rich diversity of marine life. Huge granite boulders, with their caverns and swim-throughs, create a natural playground for keen divers. It's a prime location to find leopard sharks resting on the sand and shimmering schools of glassfish that fill the crevices. There is also a whole range of smaller life to discover, including pipefish, colourful harlequin shrimp, and well-camouflaged scorpionfish.
Situated to the north of the main Similan archipelago, Koh Bon stands apart as a legendary dive site, renowned throughout Thailand and beyond. Unlike the granite boulder formations of its southern neighbours, Koh Bon is a limestone island, which gives it a unique and dramatic underwater topography. For many keen divers, a visit here is a highlight of any Andaman Sea liveaboard trip, primarily for one magnificent reason: manta rays. It is the moost reliable spot in the whole of Thailand to encounters these majestic creatures.
Richelieu Rock offers perhaps the best opportunity in Thailand to encounter a whale shark. Throughout the diving season, eagle rays and manta rays are also frequently sighted visitors. The site is so rich in life that guides will invariably plan for more than one dive here. Vast schools of trevally and barracuda patrol the currents, while a myriad of smaller species, such as frogfish, cleaner shrimp, ghost pipefish, and seahorses, can be found hiding amongst the crevices.
Final Day
Enjoy a maximum of 3 dives whiilst also enjoying breakfast and lunch on the South Siam IV, before being transferred by speedboat back to Thap Lamu late afternoon.
Similan Islands & Koh Bon (2 Days / 1 Nights - 7 Dives)
Trip highlights: manta rays, turtles, schooling fish & big pelagics
Diving environment: advanced divers, beginner divers, very popular, wall diving
Dive sites and activities: Similan Islands every day, except for Koh Bon on Tuesdays and Saturdays.
Day 1
Your liveaboard trip begins at Thap Lamu pier in Khao Lak, where a speedboat will take you to the awaiting MV South Siam IV, moored in the Similan Islands. Once aboard, you will be welcomed by the crew with a hot drink and a briefing, before settling into your cabin. All meals will be provided on this first day as well. After preparing your dive gear, the day's adventure starts with 4 dives exploring the celebrated sites of the Similans. The Similan national park boasts breathtaking underwater topography. Huge granite boulders, with their caverns and swim-throughs, create a natural playground for divers in search of sharks and schooling fish, as well as a whole range of macro life such as numerous types of nudibranch, frogfish, and pipefish.
Day 2
Today you will enjoy up to 3 dives around Koh Bon, which is renowned for frequent manta ray encounters. While mantas are the main draw, the site is teeming with other marine life. It is not uncommon to spot leopard sharks resting on the sandy bottom or whitetip reef sharks patrolling the reef edge. The nutrient-rich currents attract vast schools of fish; you can expect to be surrounded by clouds of glassfish, yellow or twin-spot snappers, goatfish, and hunting trevally. Keep an eye out in the crevices of the reef for giant moray eels, octopuses, and a variety of colourful nudibranchs. On rare and lucky occasions, a whale shark might even make a surprise appearance.
The day will see breakfast and lunch being provided and concludes with a speedboat transfer back to Thap Lamu pier, followed by your onward journey to your hotel in Phuket or Khao Lak.
Similan Islands & Koh Bon (3 Days / 2 Nights - 11 Dives)
Trip highlights: manta rays, turtles, schooling fish & big pelagics
Diving environment: advanced divers, beginner divers, very popular, wall diving
Dive sites and activities: Similan Islands every day, except for Koh Bon on Saturdays
Day 1
Get ready for an incredible day featuring 4 dives at the acclaimed sites of the Similan Islands. Your adventure will start at Thap Lamu pier in Khao Lak, where a speedboat will transfer you to the main vessel, the MV South Siam 4 liveaboard. Once on board, the crew will welcome you with a hot drink and a full briefing. After settling into your cabin and preparing your dive kit, the underwater exploration will commence. There will be full meal service today.
With its spectacular underwater landscapes and abundant marine life, the Similan National Park is a paradise for divers. The huge granite boulders create an exciting playground of caverns and swim-throughs to explore. Divers can expect to find everything from sharks and large schools of reef fish to a fantastic array of macro life like nudibranchs, frogfish, and pipefish.
Day 2
The day's itinerary is packed with superb diving around the Similans, featuring 2 dives in the morning, another in the afternoon, and finishing with either a sunset or a night dive just before dinner. Being based on a liveaboard allows you to explore the local sites and their inhabitants at a relaxed pace. The vibrant reefs are home to a spectacular array of creatures; you might encounter graceful manta rays, grey reef sharks patrolling the blue, and vast schools of giant trevally. Look closer in the corals to find clownfish defending their anemones, colourful lionfish, and perhaps even a cruising sea turtle.
Day 3
The main dive site is the Koh Bon Ridge, a long, underwater promontory extending from the island's western point. This ridge slopes down to depths of over 35 metres and is covered in a vibrant carpet of colourful soft cup corals, particularly bright yellow ones, and large sea fans.
While manta rays are the star attraction, the site is teeming with life. Due to the often-strong currents that sweep the ridge, you can expect to see large schools of pelagic fish. It is common to spot hunting packs of trevallies, along with schools of fusiliers, snappers, and barracuda.
Enjoy a maximum of 3 dives, breakfast and lunch, before being transferred by speedboat back to Thap Lamu, then on to your hotel in Phuket or Khao Lak.
Similan Islands (2 Days / 1 Nights - 7 Dives)
Trip highlights: turtles, schooling fish & big pelagics
Diving environment: advanced divers, beginner divers, very popular, wall diving
Dive sites and activities: Similan Islands
Day 1
Once at Thap Lamu Pier in Khao Lak, a speedboat will transport you to the Similan Islands, where the MV South Siam IV liveaboard is moored. You will meet the crew, get a hot drink and enjoy a welcome briefing before being assigned to your cabin. All meals are provided today as well. After setting up your dive gear, you will be ready to begin your diving day, as there will be 4 dives around the famous dive sites of the Similans. The national park has stunning underwater topography and a wide variety of marine life. The huge granite boulders with caverns and swim-throughs are a natural playground for divers searching for sharks, schools of reef fish, and a range of macro critters, including countless types of nudibranchs, crustaceans, and pipefish.
Day 2
You will enjoy up to 3 dives on the second day, the liveaboard gives you the chance to explore the sites and marine life that populate these waters at your leisure. You might encounter leopard sharks, whitetip and blacktip reef sharks, schools of batfish, moray eels resting or hunting in small crevices, as well as snapper, barracuda, triggerfish, surgeonfish, and unicornfish.
Breakfast and lunch will be served on this day. After diving has finished, you'll be transferred by speedboat back to Thap Lamu, then onwards to your hotel in Phuket or Khao Lak.
[Information is best estimate in ideal circumstances and subject to changes beyond our control. The itinerary is a guide only and may be adapted to best suit the weather, tides, currents, availability and other prevailing events. Price is for the cruise, not for an exact number of dives].
The boat operator rates their dining on the South Siam IV as
highly important and it is actually pretty good!
- Buffet-style service in the open-air social area of the upper deck of the liveaboard - choose from 2 or 3 main dishes with rice and salad.
- Thai main meal dishes and continental breakfast, there is no fixed menu
- Coffee, tea, soft drinks, hot chocolate, water, fruit and biscuits are provided free of charge.
- Beer is also available for purchase.
- Most dietary requirements can be catered for on this liveaboard - please send notice of your requirements in advance.
The daily routine is centred around diving. The boat's schedule is efficient and designed to maximise the time spent underwater. A typical day follows a rhythm of waking up, diving, eating, and resting before the next dive.
- Early morning (approx. 7 am): Wake-up call and a dive briefing.
- Morning dives: The 1st dive of the day typically takes place around 7:30 am, then breakfast, with a 2nd morning dive around 11:00 am.
- Mid-day (approx. 12:30 pm): A hot buffet lunch is served.
- Afternoon dives: The 3rd dive in the early afternoon (approx. 2 pm), then snacks, with a 4th dive scheduled for the late afternoon (approx. 5 pm).
- Evening dive (approx. 7 pm): A night dive is often an option before dinner.
- Dinner (approx. 8 pm): The final meal of the day is a hot buffet dinner.
