The deal inked by Thai foreign minister Parnpree Bahiddha-Nukara and his Chinese counterpart Wang Yi allows people from the two nations to travel to one another's country visa-free from March 1.
Thai officials hope the deal will encourage more Chinese to come and boost the kingdom's vital tourism sector, which has struggled to bounce back from the pandemic.
"This agreement is a symbol of our long-lasting friendship, trust and confidence... and help to stimulate the tourism industry in both countries," Parnpree said.
Wang welcomed the agreement, saying Thai and Chinese people "are one family."
Precise details of the visa arrangements were not announced on Sunday, but earlier this month Thai officials said the deal would allow stays of up to 30 days per visit.