South Siam 4

Similan and Richelieu Rock liveaboard

South Siam 4 liveaboard and speedboat

South Siam 4

  • 2 day 1 night Similan Islands / Koh Bon
  • 3 day 2 night Richelieu Rock, Koh Bon, Koh Tachai and Similan Islands.

South Siam 4 liveaboard (MV Somboon 4) stays out at the Similan islands all season (mid Oct to early May).

Divers are transferred from Khao Lak to the liveaboard by speedboat five times per week. Land transfers to the pier at Khao Lak are also provided from hotels in Phuket.

The dive boat does a weekly loop of all the dive sites including Koh Bon, Koh Tachai and Richelieu Rock. The flexible schedule lets you fit diving around your other travel plans. You can get a lot of dives in a short time. It’s a good value Richelieu Rock liveaboard for the 3 day 2 night trip.

Unlike other liveaboards South Siam also takes day trip divers. (Day divers can join at the Similan and Koh Bon but not at Richelieu Rock). This can make the boat busy during the day but the program is efficiently run and the day trippers have all departed by 3 pm.

Peak season holidays like Christmas, New Year and Chinese New year are busiest (you need to book early for these dates). Because of all the comings and goings and the moving between islands there are fewer beach excursions on a South Siam liveaboard than on other boats.



South Siam 4 deck plan

  • Sleeps 24 guests in double and twin bed cabins
  • Length 28 metres, beam 6.5m
  • All cabins are air conditioned
  • Shared bathrooms
  • Cruising speed of 10 knots
  • Large sun deck and large shaded deck
  • Tasty and plentiful Thai and international food
  • PADI Advanced courses taught on board


South Siam 4 price


2 days 1 nights (7 dives) at the Similan Islands

  • Double bed or twin share cabin: 13,900 baht per diver / 9,900 baht per non diver
    Mon-Tues or Thurs-Fri or Fri-Sat. Depart morning, return next day evening

3 days 2 nights (11 dives) at the Similan Islands, Koh Bon, Koh Tachai and Richelieu Rock

  • Double bed or twin share cabin: 22,900 baht per diver
    Tuesday to Thursday or Saturday to Monday

4 days 3 nights (15 dives) at the Similan Islands, Koh Bon, Koh Tachai and Richelieu Rock

  • Double bed or twin share cabin: 26,900 baht per diver
    Friday to Monday or Monday to Thursday

Price includes: Dive guide, tanks, weights & belt, all meals, drinking water, tea, coffee, soft drinks, return hotel transfers from Phuket main beaches (Patong, Kata, Karon) and central Khao Lak (Nangthong, Bangniang).

Price excludes: Equipment rental (500 baht per set per day), nitrox, alcoholic drinks, towels, marine park fees, outside area transfers.

Note: To dive at Koh Bon, Koh Tachai and Richelieu Rock divers must be advanced certified (or equivalent experience) with dives logged within the last year. The PADI Advanced course can be completed on board for 8,500 baht. Or you can dive with a private divemaster (extra charge of 2,000 baht per day).

Similan (incl. Koh Bon) Marine National Park Fee:
500 Baht for entry into the Similans (divers and nondivers) plus…
200 Baht per diver per day

Similan Islands-Richelieu Rock Marine National Park Fee:
1,500 Baht for entry into the Similans – Surin (divers and non-divers) plus…
200 Baht per diver per day

Please note that the National Park Fee is set by the National Park and is subject to change without notice.

Schedule & Itinerary

South Siam 4 itinerary and schedule

Mon: Similan Islands

Tue: Similan Islands / Koh Bon / Koh Tachai

Wed: Surin Islands / Richelieu Rock / Koh Tachai

Thur: Similan Islands

Fri: Similan Islands

Sat: Similan Islands / Koh Bon / Koh Tachai

Sun: Surin Islands / Richelieu Rock / Koh Tachai

*Itineraries are subject to change.

If this itinerary doesn’t work for you the sister ship South Siam 3 runs a similar schedule with different dates.

  • Departs every morning except Wednesday and Sunday.
  • Returns every evening except Wednesday and Sunday.

Basically you can join South Siam 4 any day except Wednesday and Sunday. You can depart the boat any day except Wednesday and Sunday.

If you want to dive Richelieu Rock, schedule a Wednesday or Sunday into your trip.

On the first day you will be collected from your hotel in Phuket or Khao Lak in the morning (6.00 am-7.30 am depending on your hotel) and transferred by minibus to Tap Lamu Pier. From there you will be transferred by speedboat to the South Siam 4 liveaboard.

On the last day you will be transferred off South Siam 4 in the afternoon and arrive back at your hotel in the evening.

Book / Enquiry

    Online booking

    Don't like forms?
    Hotline: +66 81 2727556

    1. Tell us the dates you are interested in. We’ll check available options and provide you with a clear breakdown of prices.
    2. When you are ready to go ahead and book we’ll reserve your place(s) and email you the secure online payment instructions.
    3. 10% deposit to confirm your booking. Payment is online by credit card or paypal (no booking fee or credit card fee), or by bank transfer.
    4. Balance payable 60 days before the trip departure date.

    Payment method

    project aware

    South Siam 4 reviews

    Hello Paul, Just a belated note to thank you for sorting out this Koh Bon trip for us, it was another excellent day of diving and we saw a giant manta ray, which was just blinking awesome! Back in cold England at miserable work. Oh well, it was a great holiday! Best wishes, Jess

    This post is also available in: Italian Thai

    This post is also available in: Italian Thai