The Centre for the Covid-19 Situation Administration (CCSA) reported a new daily record of 9,692 new cases and 67 more deaths on Friday, taking the total number of infections to 381,907 and 3,099 fatalities, reports Xinhua news agency.
Five days after the semi-lockdown measures have been in effect in Thailand's worst-affected provinces, the number of cases continued to rise sharply.
Tougher measures such as the closure of more businesses and public mobility restrictions have been planned to tackle the current situation, CCSA spokeswoman Apisamai Srirangsan told a daily briefing on Friday.
Thailand is now facing a threat of a more contagious Delta variant while lagging behind in the vaccination rollout.
As of Thursday, less than 5 per cent of its 70 million population have been fully vaccinated in the country's plan to inoculate 70 per cent of its population by the end of this year.
Despite the worsening Covid-19 situation nationwide, the popular tourist island Phuket will likely to see more foreign visitors than earlier forecast under the Phuket Sandbox, a pilot tourism reopening project that Thailand bets on to save its tourist-reliant economy.
Tourism Authority of Thailand (TAT)'s Phuket Office director Nanthasiri Ronsiri said on Thursday that a total of 5,473 foreign tourists have so far visited Phuket since July 1, generating some 190 million baht ($5 million U.S. dollars) in tourism-related income.
More tourist islands including Ko Samui have opened to fully vaccinated local and foreign visitors since Thursday.