Thailand and China will permanently waive visa requirements for each other's citizens from March, Thai Prime Minister Srettha Thavisin said.
Thailand waived visas for Chinese nationals in September in a bid to boost tourist arrivals.
The programme saw strong response at a time when Thailand was starting to lose its appeal for Chinese travellers.
More than 22,000 Chinese entered the Southeast Asian nation in the first two days of the waiver, authorities said.
"Right now we're ready to open the country and to take good care of tourists in both countries mutually. This is welcoming news," Mr Srettha said at a press conference on Tuesday.
"This is an upgrade to the relations [between Thailand and China and a boost to the significance of Thai passports," he said.
The Chinese are the second largest group of foreign visitors to Thailand, after Malaysians.
The Tourism Authority of Thailand said in November that it expected up to 3.5m Chinese visitors for the whole of 2023 - which is still short of its 4m-target.
This is less than half the nearly 11 million Chinese tourists who went there in 2019, but would still mean a marked improvement from 2022, when it received just 270,000 of them.
A shortage of low-cost flights post Covid and a slowing Chinese economy are among the reasons why tourists are reluctant to visit Thailand. But some people have also raised safety concerns, after rumours that tourists have been kidnapped and sent across the border to work in scam centres in Myanmar or Cambodia. Tourists were also nervous following a shooting in Bangkok's most famous shopping mall that killed a Chinese mother of two children in October last year.
The tourism authority has set a target of 8.2m Chinese tourists for 2024.
China too has been waiving visa requirements to entice tourists.
Last November, it announced a visa-free trial for visitors from France, Germany, Italy, the Netherlands, Spain and Malaysia.
The programme, which started in December, will last till the end of November this year.
