Short answer
Mu Ko Lanta National Park reported on 7 September 2026 that coral was bleaching at all five survey sites around Koh Rok Nok and Koh Rok Nai, at about 5 to 10 percent at each site. The survey was run with the marine research centre in Trang. The park also found coral killed in the 2024–2025 bleaching event. It limits activities at fragile spots and asks visitors to avoid sunscreen that harms coral. No reef closure had been announced in the department's news to 28 October 2026.
What the park reported
On 7 September 2026 the Department of National Parks published a report from Mu Ko Lanta National Park in Krabi Province. The park and the department's marine research centre in Trang surveyed coral at five stations, three at Koh Rok Nai and two at Koh Rok Nok, and found bleaching at every one of them.
The park put the share of bleached coral at about 5 percent at the site in front of the ranger station on Koh Rok Nok and at the north side of Koh Rok Nai, and at about 10 percent at the other three. It named the main corals affected as Porites, Pavona and blue coral (Heliopora). The survey also found traces of coral killed in the 2024–2025 bleaching event.
What the park is doing about it
The park says it will keep monitoring sea temperature and has underwater teams checking the health of the reef. It is limiting tourism activities at fragile spots and campaigning for operators and visitors to use environment-friendly services and to avoid sunscreen with chemicals that damage coral.
The report is a warning and a plan, not an order. It says the park is ready to announce temporary protection for the worst-hit reef areas if the risk grows. We found no such announcement in the department's news feed up to 28 October 2026.
What it means for visitors
Koh Rok and Koh Ha are on the department's 2026 closure list: Koh Rok from 1 June to 30 September and Koh Ha from 1 August to 30 September, as published in the Royal Gazette on 9 January 2026. Both closure periods have ended. Check the park's notices before you book a trip there, because temporary protection could change what is open.
The report's request to visitors is short: follow the park rules and avoid sunscreen that harms coral. A mineral sunscreen is the usual way to do that, and our guide to reef-safe sunscreen explains which ingredients the marine parks object to.
What it means for our Krabi days
Our Krabi 4 Islands and Hong Islands speedboat tours start from $35 per person and do not visit Koh Rok. The report covers only the five Koh Rok stations and says nothing about the reefs on our routes. Mask, snorkel and life jacket are included; fins are not.
The national park fee on our tour is paid in cash at check-in: 200 baht per adult and 100 per child on the 4 Islands day, and 300 and 150 on the Hong Islands day. Bring reef-friendly sunscreen and water shoes. For the wider rules, see our guide to reef-safe sunscreen in Thailand.
Practical checklist
- Choose a sunscreen without chemicals that harm coral.
- Follow the rangers' instructions and the park rules at every stop.
- Check the national park's notices before booking Koh Rok or any other reef trip.
- Bring cash for the national park fee on our Krabi days.
Questions and answers
How much coral was bleached at Koh Rok?
Mu Ko Lanta National Park reported bleaching of about 5 to 10 percent at each of five survey sites around Koh Rok Nok and Koh Rok Nai, in a report published on 7 September 2026.
Is Koh Rok closed because of the bleaching?
The department's news up to 28 October 2026 shows no closure for bleaching. The park says it may announce temporary protection of the worst-hit areas if the risk rises.
Do our Krabi tours go to Koh Rok?
No. Our Krabi 4 Islands and Hong Islands days do not visit Koh Rok, and the report says nothing about the reefs on our routes.
Which sunscreen does the park ask visitors to avoid?
The report asks visitors to avoid sunscreen with chemicals that damage coral. It does not list the ingredients; our reef-safe sunscreen guide covers them.