A 27-year-old Thai tourist who went missing while visiting Phu Soi Dao National Park in Uttaradit was found safe after a seven-day search.
The park's restaurant owner said that Thanwarich Mateema had walked back by himself.
Park officials did not ask about the details since the tourist was very tired. He was given food and sent to a hospital for a check-up.
The tourist walked out of the forest along a natural path until he arrived at the Phu Soi Dao waterfall area, near the restaurant, said the national park chief.
Mr Thanwarich's family rushed to meet him.
The solo trekker, from Maha Sarakham, visited the park last Thursday. Park officials noticed that he had gone missing because he registered when entering the park but did not show up at the office at the end of the mountainous trail on the same day.