Visitors to national parks must now make reservations before entering, the Ministry of Natural Resources and Environment says.
Parks are expected to be opened before the end of the month but visitors who usually can just walk in, must now register.
"Online reservations will be required for health reasons," Environment Minister Varawut Silpa-archa said.
The government's Centre for Covid-19 Situation Administration (CCSA) is expected to lift many remaining lockdown measures next Friday.
All Covid-19 vulnerable sites including concert events, pubs and karaoke shops, massage parlours, amusement parks and national parks are expected to be reopened.
Mr Varawut said the same restrictions need to be in place at parks to help visitors to follow social distancing policies.
"By next week, we are going to have an announcement of what visitors should do and should not do while visiting the parks," he said.
"One of the certain measures is that visitors must make a reservation first. They cannot just walk in."
He said the Department of National Parks (DNP) will use a sophisticated reservation system to control the number of park visitors.
He said national parks have high visitor rates, citing the number of people at Doi Inthanon National Park in Chiang Mai province on 30 Dec 2018 as being recorded at 20,469, according to DNP figures.
Apart of introducing the reservation policy, the minister said the DNP must require visitors to check in via the "Thai Chana" mobile application.
"I understand that there will be problem at the early stage of implementation so we are going to have a hotline to provide help and information for those who are in need," he said.
He said the reservation and check-in system is likely to be implemented until the Covid-19 pandemic is under control.
However, Mr Varawut said the DNP will consider using both measures in the long run in a bid to keep the number of park visitors at an optimal level, so the ecological system will not be strained.
He said the two-month lockdown during the Covid-19 crisis has allowed time for ecology in national parks to recover. The ministry is also considering new land zoning plans for national parks. Each national park will have zoning regulations based on public accessibility.