Authorities plan to control the number of visitors to national parks by limiting sales of tickets, which will only be available online at convenience stores.
Thanya Netithammakun, director-general of the Department of National Parks, Wildlife and Plant Conservation, said on Wednesday the move was conservation-oriented.
It would start with popular national parks in the near future, as they were usually packed with tourists on long holidays.
Tickets would no longer be available at the entrances of national parks, but would be sold at convenience stores, he said.
"This way we can control the number of visitors to individual parks. If the number of tourists reaches the set maximum, no more tickets will be issued until some visitors leave that place. The system is still being developed, but will be finished soon," Mr Thanya said.
He dismissed any concerns over lost revenue. Admission fees were a byproduct, he said. The department was actually tasked with conserving national parks, not promoting tourism.
Park rangers were also being trained in first aid, so they can take good care of visitors who might fall ill or be injured, he said.
"In the near future we will have ambulances at the five most popular national parks," Mr Thanya said.
He referred to Ao Phang Nga National Park in Phangnga province, Doi Inthanon National Park in Chiang Mai, Hat Nopparat Thara-Mu Ko Phi Phi National Park in Krabi, Khao Yai National Park mainly in Nakhon Ratchasima province, and Namtok Phlio National Park in Chanthaburi.