Meet Nok: A Koh Tao Dive Instructor on Coral, Whale Sharks, and What Tourists Do That Makes Her Cringe
Nok Srisomboon has been a dive instructor on Koh Tao for nine years. She's logged over 5,000 dives, trained hundreds of new divers, and spent more time underwater around this island than most fish. She grew up in Surat Thani on the mainland, came to Koh Tao at 22 for a PADI course, and never left.
We met at a cafe in Mae Haad at 7 AM — early, because her first dive group launched at 8:30. She was wearing a rash guard, eating pad krapao over rice, and checking the weather app with the intensity of a pilot.
How did you end up staying on Koh Tao?
I came for Open Water in 2017. Four days, 8,500 baht. On the third dive — at Japanese Gardens, which is a shallow, easy site — I saw a seahorse. Just sitting there on a piece of coral, holding on with its tail, completely calm. The instructor pointed it out and I basically lost my mind underwater.
I went home to Surat Thani and lasted two weeks. Then I came back, did Advanced, did Rescue, did Divemaster, did Instructor. Now I teach. I've seen that seahorse's descendants — they're still at Japanese Gardens. I check on them.
Which dive shop should someone choose? There are seventy on the island.
Fifty that are good. Ten that are excellent. Ten that I'd avoid.
Here's what to look for: instructor-to-student ratio (4:1 maximum for Open Water, never higher), whether they own their own boat or share, how they handle equipment maintenance, and — this is important — whether they participate in coral conservation.
Ask to see the training pool and the boats. If the boats look neglected, the safety equipment is probably neglected too. And read recent reviews — not the reviews from 2020, the ones from last month.
I won't name shops I don't like. But I'll say that the cheapest option is usually cheap for a reason.
Best dive site on Koh Tao?
Sail Rock. And it's not close. A granite pinnacle rising from the deep, covered in life — enormous schools of batfish, barracuda, chevron, sometimes bull sharks. The chimney is a vertical swim-through from 18 meters to 5 meters that's one of the most thrilling things you can do underwater.
And in March-April, the whale sharks come. I've seen whale sharks at Sail Rock seven times in nine years. Each time feels like the first time. Your brain genuinely cannot process the size. You see a shadow, you think it's a manta ray, and then it keeps getting bigger and bigger and it's a whale shark and you forget to breathe (which, underwater, is a problem).
What do tourists do that makes you cringe?
Standing on coral. STANDING ON CORAL.
(She puts down her fork)
Coral is an animal. It grows about one centimeter per year. When a tourist stands on a coral head for a photo or because they're tired or because they can't control their buoyancy, they can destroy decades of growth in one second. One second.
I teach every Open Water student: if you can't maintain buoyancy, go up. Never go down onto the reef. I'd rather you surface than touch the coral. Some instructors don't emphasize this enough. It makes me angry.
Also: chemical sunscreen. The oxybenzone and octinoxate in most sunscreens bleach coral on contact. Use mineral sunscreen — zinc oxide-based. It's more expensive and leaves a white film on your skin. I don't care. The reef is more important than your tan.
How are the reefs doing?
Mixed. Some sites are in great shape — Japanese Gardens, Twins, and the deeper sites at Sail Rock have healthy coral coverage. Other sites, especially the shallow ones near Sairee where snorkelers go, have taken damage from tourism, anchoring, and the 2010 and 2016 bleaching events.
The good news: Koh Tao has the most active coral restoration program of any island in Thailand. Multiple dive shops participate in coral nursery projects — growing coral fragments on underwater frames and transplanting them to damaged reefs. New Heaven Reef Conservation Program at Chalok Baan Kao is the leader — they've planted thousands of coral fragments. You can volunteer for a day.
The bad news: rising water temperatures are the biggest threat, and that's not something local conservation can fix.
Freediving has gotten big here. Thoughts?
It's amazing. Ten years ago, freediving on Koh Tao was five people. Now there are multiple schools, international competitions, and freedivers from all over the world training here.
The water conditions are perfect — warm, calm, and clear. Apnea Total and Blue Immersion are both excellent schools. A Level 1 course is about 7,000-9,000 THB for two days. If you can hold your breath for 30 seconds now, you'll be doing 2-3 minutes by the end of the course.
What I love about freediving is the silence. Scuba is noisy — your regulator, your bubbles. Freediving is just... water. And the marine life reacts differently. Fish don't swim away from you. They come closer.
Best non-diving experience on Koh Tao?
John-Suwan Viewpoint at sunset. It's a 30-minute hike from Chalok — steep, sweaty, and totally worth it. At the top, you can see Shark Bay on one side and the open ocean on the other. Bring a beer. Watch the sky turn colors.
Also: Tanote Bay for snorkeling. Walk in from the beach, swim out 20 meters, and you're in a coral garden with clownfish, trigger fish, and sometimes a resident turtle. No dive certification needed. No boat needed. Just a mask and some reef-safe sunscreen.
What do you wish tourists knew?
The ocean here is alive. Every piece of coral is an animal. Every fish has a territory. The reef is a community — as complex as a city. When you dive or snorkel, you're visiting someone's home.
Treat it that way. Don't touch. Don't take. Don't stand on the furniture.
And tip your dive instructor. We work long hours in the sun for modest pay because we love the ocean. A 200-baht tip after a course costs you six dollars and means a lot.
Will you ever leave Koh Tao?
(Long pause)
I go home to Surat Thani for Songkran and New Year. My mother asks when I'll get a real job. I tell her I have a real job — I show people the most beautiful thing on the planet.
She still doesn't understand. But she stopped asking last year. So... progress.
Nok dives daily out of Mae Haad. If you're chaining Thai islands afterward, Koh Chang near the Cambodian border trades dive boats for jungle waterfalls and far fewer crowds.
And for more of the same world-class, budget-friendly diving abroad, Nusa Lembongan off Bali delivers manta rays and mola mola from a similarly tiny island base.
