Signs banning public nudity have been put up at beaches on Koh Phangan, home of the full moon parties, after frequent complaints about tourists going naked.
Local officials put up the signs on Wednesday and handed out leaflets to visitors to the island and local tourism businesses, including restaurants and hotels at Zen Beach and Secret Beach.
Public nudity is outlawed in Thailand and violators could have their visas revoked, police said.
They said there had been complaints about foreign tourists swimming, sunbathing, playing music and doing other activities while naked at Secret Beach and Zen Beach.
However, public nudity is against Thai law, with a fine of up to 5,000 baht.
The no-public-nudity campaign follows the arrest of a Polish couple seen naked and hugging each other in the middle of a road on the island on Monday.
