Sunscreens containing oxybenzone, octinoxate, 4-MBC or butylparaben are banned inside Thailand's marine national parks, with a fine of up to 100,000 baht (as of October 2026). It is not a national ban: the same products are sold legally in Thai shops and may be used on beaches outside the parks.
The Department of National Parks, Wildlife and Plant Conservation (DNP) introduced the rule on Wednesday 4 August 2021 to protect coral reefs, and its director-general repeated it on Thursday 16 October 2025, telling every marine national park to enforce it strictly. The four chemicals, the department says, harm coral larvae, disrupt reproduction and contribute to bleaching.
For a visitor, the rule comes down to one habit: read the ingredient list before a snorkeling or diving trip, not the front of the bottle. This page covers the law and the label. For protecting your skin from the Thai sun, see our guide to heat and sun in Thailand.
The marine park sunscreen rule (October 2026)
- Banned ingredients
- Oxybenzone, octinoxate, 4-methylbenzylidene camphor (4-MBC), butylparaben
- Where
- Inside Thailand's marine national parks
- In force since
- 4 August 2021; reaffirmed 16 October 2025
- Maximum fine
- 100,000 baht
- Legal basis
- Sections 20 and 47 of the National Park Act 2019
- Enforced by
- Park officers of the DNP
- Same announcement
- Do not touch or stand on coral; keep at least 2 m from reefs
What the rule says
The ban is a national park rule, made under the National Park Act of 2019. When the DNP restated it in October 2025, it cited Section 20 of the Act together with Section 47, the penalty section, which gives a maximum fine of 100,000 baht. The ban covers bringing and using sunscreen that contains any of the four substances inside a marine park.
It says nothing about selling. Sunscreens with these ingredients are not banned from sale in Thailand, and the park rule does not reach the hotel pool. The question is only where you are when you put it on, and where you swim afterward.
Which parks it covers
The rule applies in all of Thailand's marine national parks, not a chosen few. On the Andaman side these include the parks most visitors reach on day trips:
- the Similan Islands and Surin Islands, open from mid-October to mid-May;
- Hat Noppharat Thara–Mu Ko Phi Phi, which includes Maya Bay;
- Mu Ko Lanta, with Koh Rok and Koh Ha;
- Tarutao, the park close to Koh Lipe.
In the Gulf of Thailand, Ang Thong off Koh Samui is a marine national park too. We could not read the DNP's own list of parks, so this is not a complete list.
A simple test works for most trips: if a national park fee is part of your ticket or is collected on the boat, you are going into a park, and the sunscreen rule applies there. Our guide to the best time for the Thai islands explains when the Andaman parks close for the monsoon.
How to read a sunscreen label
Ingredient lists use international chemical names, so the banned filters often appear under a different name from the one in the rule. Look at the "active ingredients" or the full ingredient list on the back.
| Banned in the parks | What the label may say instead |
|---|---|
| Oxybenzone | Benzophenone-3, BP-3 |
| Octinoxate | Ethylhexyl methoxycinnamate, octyl methoxycinnamate |
| 4-MBC | 4-Methylbenzylidene camphor, enzacamene |
| Butylparaben | Butylparaben, butyl 4-hydroxybenzoate |
Other UV filters are not on the list. Mineral filters such as zinc oxide and titanium dioxide are not banned, and when the rule was launched in 2021 a Kasetsart University marine scientist advised divers to use zinc oxide products. Other chemical filters, such as homosalate and octocrylene, were not named in the 2025 restatement either.
"Reef safe" on the front is a marketing phrase, not a Thai approval. No official scheme checks the label. The DNP does encourage products marked "reef safe" or "reef friendly", but the legal test is the four ingredients, so check the list on the back every time.
What happens if a ranger finds the wrong sunscreen
The maximum penalty is a 100,000-baht fine. That is the ceiling the law allows, not a fixed charge, and we found no reported case of a tourist being fined under this rule (as of October 2026).
When the ban began in 2021, the director of the Office of National Parks described a softer approach: officers would not confiscate banned products but would hold them and give them back when the visitor left the park. A Kasetsart University scientist estimated at the time that 80 to 90 percent of package-tour visitors to the marine parks go diving, and park staff planned to ask tour operators to explain the ban before each trip. The 2025 announcement told every park to enforce the rule strictly, so do not count on leniency.
The other reef rules in the same announcement
The October 2025 statement was not only about sunscreen. The DNP also asked visitors to:
- not touch, stand on or handle coral;
- stay at least 2 meters away from coral reefs;
- throw nothing into the sea;
- follow park officers' instructions.
Taking coral or shells home is a separate problem at customs; see what you cannot take home from Thailand. If you are curious what else lives on the reefs, our page on sharks in Thailand covers the blacktips that use Maya Bay as a nursery.
Practical ways to stay within the rule
- Check before you pack. If your usual sunscreen contains any of the four, buy a different one at home, where you can read labels in your own language.
- Put on a compliant product before the boat leaves. Sunscreen applied in the hotel still washes off in the park.
- Cover up instead. A long-sleeved rash guard and a hat mean you need less sunscreen at all.
- Keep the bottle. If a ranger asks, the ingredient list is your evidence; decanted sunscreen in an unmarked bottle proves nothing.
Frequently asked questions
Is sunscreen banned in Thailand?
No. Only sunscreens containing oxybenzone, octinoxate, 4-MBC or butylparaben are banned, and only inside marine national parks. They are sold legally in Thailand and can be used elsewhere, such as at your hotel or on beaches outside the parks.
What is the fine for using banned sunscreen in Thailand?
Up to 100,000 baht under the National Park Act 2019. That is a maximum, not a standard fine, and we found no reported case of a tourist being fined. In 2021 park officers said they would hold banned products until the visitor left the park.
Is zinc oxide sunscreen allowed in Thai marine parks?
Yes. Zinc oxide and titanium dioxide are not among the four banned ingredients. A Kasetsart University marine scientist recommended zinc oxide products to divers when the ban started in 2021. Check that the same product does not also contain one of the banned chemical filters.
Does a "reef safe" label mean a sunscreen is allowed?
Not necessarily. "Reef safe" is an unregulated marketing term. The Thai rule names four ingredients, so the only reliable check is the ingredient list on the back of the bottle.
Sources
- Khaosod English – Tourists face penalty for banned sunscreens in Thai marine parks (17 October 2025) (checked October 2026)
- Bangkok Post – Coral-damaging sunscreens banned in marine parks (5 August 2021) (checked October 2026)
- Department of National Parks – Maya Bay survey during the 2026 closure (Thai) (checked October 2026)