Diving Koh Rok - Lak Siam
The long and extensive sloping reef covering almost the entire east coast of Koh Rok Noi is one of the best dive sites at the Koh Rok islands.
The sandy beach is fringed with a huge area of corals which makes this a super snorkeling spot, and as we head a little deeper we encounter a sloping reef which runs to 15 - 20 m the entire length of the island. The snorkeling here is as good as Koh Haa Lagoon.
Dropping in the middle of Lak Siam, we can either dive with our right, or left shoulder to the reef.
The slope is covered extensively with a huge variety of hard and soft corals, creating a dense and rich coral reef including branching corals, bubble corals, mushroom corals, lettuce corals, anemones, brain corals, leather corals, soft corals and sea fans. We think this is one of the best dives at Koh Rok.


The dense corals are home to millions of reef fish, including moorish idols, snapper, fusiliers, grouper, wrasse, moray eels, angelfish and butterfly fish, clownfish, shrimp, sea cucumbers, snails, slugs, urchins, feather stars, surgeonfish, parrotfish and many, many other species.
We can also find several species not commonly seen around our other dive sites, such as the convict surgeonfish and more rare species of butterflyfish and angelfish.
Here you will definitely find nemo.


Along the deeper fringes of Lak Siam we find an almost continuous line of giant gorgonian sea fans, giant barrel sponges, and bubble corals, the favourite food of the many turtles which we often see along this reef.
Indeed, it is unusual not to see at least one or two turtles on this dive, sometimes many more.
Book online to save 10% on dive trips and scuba courses on Koh Lanta.
The southerly part of Lak Siam becomes a more rocky slope and it approaches the shallower end point of the Hin Ngam dive and begins to take on similar features to the end of the Hin Ngam dive.
Visibility: | 10m - 30m + |
Level of Diving: | All Levels |
Snorkeling: | Yes |
Depth: | 0m - 20m + |
Journey Time: | 50 - 60 mins |

- Koh Haa Islands
- Koh Haa One
- Koh Haa Lagoon
- Koh Haa Yai
- Koh Rok Islands
- Koh Rok Lak Siam
- Koh Rok Hin Ngam
- Koh Rok Pak Rong
- Shark Point/Anemone Reef
- Shark Point
- Anemone Reef
- Phi Phi Leh
- Phi Phi Palong
- Phi Phi Viking
- HTMS Kledkaeo Wreck
- Hin Klai
Find out more at the Thai Department of National Parks.
Certified Diver Prices | Online Price | Walk-In Price |
Koh Haa / Koh Rok(all levels of diving) | ฿3,150 | ฿3,500 |
Koh Bida / Koh Phi Phi(all levels of diving) | ฿3,150 | ฿3,500 |
Hin Daeng & Hin Muang(experienced divers only) | ฿3,950 | ฿4,300 |
Shark Point & Anemone Reef(experienced divers only) | ฿3,950 | ฿4,300 |
- Minimum Open Water Diver, or equivalent.
- All trips are 2-tank dives. Includes free equipment rental, lunch & soft drinks on the boat.
- Does not include Marine Park Diving Fee: Adult ฿600, Child: ฿400 per day.
Our Boat Trip Schedule
Our dive trips depart Koh Lanta in the morning every day from the south end of Long Beach, returning to Koh Lanta around 1:30 - 2pm, depending on how the day goes.
Week Day | Boat 1 | Boat 2 |
Monday | Koh Rok Islands | Koh Rok Islands |
Tuesday | Koh Haa Islands | Hin Daeng & Hin Muang |
Wednesday | Koh Bida / Phi Phi | Koh Bida / Phi Phi |
Thursday | Koh Haa Islands | Koh Haa Islands |
Friday | Koh Haa Islands | Hin Daeng & Hin Muang |
Saturday | Koh Bida / Phi Phi | Koh Bida / Phi Phi |
Sunday | Koh Haa Islands | Koh Haa Islands |
- All trips are 2 dives a day
- Trips depart from the beach at our dive shop @ Lanta Castaway Beach Resort
- Trips Depart 8/9am, return 2pm
- Dive & Relax is open from Oct 15 - May 15.
- E-mail us info@diveandrelax.com in advance with any questions, or to make a booking.
We may schedule a Shark Point & Anemone Reef dive trip or a KledKaeo Wreck dive trip upon request. A minimum of 5 divers are required for these trips, please let us know if you are interested.
We love to dive as much as possible during the high season, however all our dive trips depend on the weather, sea conditions, currents and minimum numbers and may be subject to change at short notice.
Book online to save 10% on dive trips and scuba courses on Koh Lanta.
For more information on our weather and climate, check out the best time to visit Koh Lanta.