A Girls That Scuba Adventure Through Surin, Koh Bon, Koh Tachai and Richelieu Rock
The Smiling Seahorse’s last trip felt very exclusive, with only 9 guests onboard, including 6 members of the “Girls That Scuba” group. It was also the occasion to welcome a new female member to our team: Laurence, our dive master, who wrote this blog post today 🙂
![]() |
![]() |

Starting with a check dive at the Surin Islands
We started the itinerary with a check dive around the Surin Islands, where we immediately bumped into a cute yellow boxfish, some peacock mantis shrimp and an eagle ray that came to greet us. One group was also lucky enough to see the elusive giant guitar shark, which had been spotted several times this season but had stubbornly refused to pose for a photograph!
We knew then that this trip was going to be a good one.
The day continued south of Surin with a night dive. The highlight was seeing sleeping parrotfish tucked safely inside their protective bubbles, beautiful sailfin surgeonfish and active moray eels hunting out of their holes. Our night dive was a little later than usual this week: we jumped in at around 8 pm, when the sea was completely dark and the nocturnal critters were already well on their way.
![]() |
![]() |
Marble rays and schools of fish at Koh Bon
After a good night’s sleep, we made it to Koh Bon, where our first dive took us to the Pinnacle. Here, we were lucky enough to encounter four massive marble rays resting at the bottom. They stayed with us long enough for everyone to enjoy the encounter, making for one of those special dives where there was no need to rush anywhere.
Out in the blue, we were mesmerised by a school of barracuda and a second eagle ray swimming straight towards us. The curious batfish also decided to buddy up with us for a while, adding another memorable encounter to the dive.
![]() |
![]() |
The green monster arrives at Koh Tachai
Our next stop was Koh Tachai, where we dove twice, first on the second pinnacle and then on the first pinnacle.
The visibility was exceptional, and the huge schools of fish reminded us of a ballet as they moved together through the blue. But then the green monster arrived!
One moment the visibility was perfect and the water was a comfortable 31°C. The next, our view became blurry and the temperature dropped to 27°C almost instantly. The feeling of the green monster passing over the dive site is quite special. Fish tend to avoid it, so the closer the green water gets to you, the more schools of fish are pushed towards you.
We especially enjoyed the swim-through on the first pinnacle, as well as the beautiful purple corals covering parts of the reef. Koh Tachai can offer some spectacular wide-angle scenery, particularly when the visibility and currents come together in your favour.
![]() |
![]() |
A full day of diving at Richelieu Rock
From there, we sailed to Richelieu Rock for a four-dive day. As always, Richelieu Rock had plenty to keep us busy, from tiny macro life hiding among the rocks to huge schools of fish moving around the pinnacle.
Our new favourite friend, the baby seahorse, was still in the same spot where we had seen him the previous week. Our regular partners in crime were all there too: harlequin shrimp, cowries, ghost pipefish, batfish and enormous schools of fusiliers.
During the afternoon dives, the action continued out in the blue. We were thrilled to watch schools of giant trevallies, jacks and yellowfin barracuda heading out on the hunt. Richelieu Rock is particularly special because you can spend one dive searching carefully around the reef for tiny creatures and then turn towards the blue and suddenly find yourself surrounded by large schools of pelagic fish.
A few of us were also lucky enough to get a glimpse of the future generation of Clark’s anemonefish before they hatched. The eggs were already showing the tiny eyes of the developing fish, making it impossible not to stop and take a closer look. We couldn’t wait to come back on the 10th and see how they had grown.
![]() |
![]() |
Finishing the trip under the stars
We finished off the trip with our usual Ti’ Punch and barbecue night, under the shining stars as we sailed back towards Ranong. After several days of diving, plenty of great marine-life encounters and a lot of laughter onboard, it was a lovely way to end the cruise.
It was really nice to meet you all, guys, and we can’t wait to have you back onboard again!
![]() ![]() |
![]() ![]() |
A few words from our guests
![]() |
![]() |
Are you in Thailand and an underwater photography adept?
Let us be your guide for your next underwater photography trip to the Similan and Surin Islands.
Read our Underwater Photographer’s Guide to the Surin and Similan Islands!
Discover More
- Surin Islands – Explore the reefs and marine life of Thailand’s remote Surin Islands.
- Koh Bon – A favourite Andaman Sea dive site for rays, reef fish and encounters in the blue.
- Koh Tachai – Discover the pinnacles, schooling fish and colourful coral of Koh Tachai.
- Richelieu Rock – One of Thailand’s most famous dive sites, renowned for macro life and large schools of pelagic fish.
- Underwater Photographer’s Guide to Thailand – Practical tips for planning an underwater photography trip in the Surin and Similan Islands.

















One Response
Amazing article, Thanks for this wonderful information.