A new daily record of 13,655 Covid-19 cases, and 87 more fatalities, were registered over the previous 24 hours, the Public Health Ministry reported on Thursday morning.
There were 13,110 cases in the general population and 545 among prison inmates.
Also on Wednesday, 7,921 Covid-19 patients were diagnosed recovered and were discharged from hospitals.
Since April 1, around when the third wave of Covid-19 began, there have been 424,269 Covid-19 patients, 284,951 of whom have recovered.
Since the pandemic started early last year, there have been 453,132 Covid-19 cases, 312,377 of whom recovered.
The death toll was at 3,603 in the third wave and 3,697 from the beginning of the pandemic early last year.
The previous high of daily Covid-19 cases was 13,002 on Tuesday, reported on Wednesday, when there were 108 fatalities.
The Department of Disease Control said in its afternoon briefing that the 87 fatalities were aged 24-93 years, 42 had hypertension and nine were free of chronic illness. Thirty-six either lived in or visited outbreak areas and 22 caught the virus from other family members.
Bangkok logged 44 more fatalities, and there were six in Pathum Thani, five in Nakhon Sawan, four each in Samut Sakhon and Pattani, three each in Nakhon Pathom, Samut Prakan, Songkhla and Ratchaburi, two each in Chiang Mai, Samut Songkhram and Surin and one each in Chiang Rai, Phitsanulok, Ayutthaya, Sing Buri, Udon Thani and Ubon Ratchthani.
The 13,655 new cases included 13,099 local infections spread through all provinces, and 11 imported cases.
Of the local infections, 9,254 were confirmed at hospitals and 3,845 via mass testing. Greater Bangkok had 5,732 new cases and 60 new fatalities, and the four southernmost border provinces 880 new cases and seven moredeaths.
Bangkok had the most new cases at 2,893, followed by 965 in Samut Sakhon, 895 in Samut Prakan, 620 in Chon Buri, 416 in Nonthaburi, 365 in Pathum Thani, 293 in Nakhon Ratchasima, 289 in Pattani, 274 in Suphan Buri (including 119 in a new cluster at a chicken-processing plant in Song Phi Nong district) and 261 in Rayong.
The 11 imported cases were from the United Arab Emirates (3), Malaysia (4) and Cambodia (4).
On Wednesday 137,058 people received treatment for Covid-19 at hospitals - 78,197 at conventional hospitals and 58,861 at field hospitals - of which 3,856 suffered from lung inflammation and 889 were dependent on ventilators.
Global Covid-19 cases rose by 553,711 in 24 hours to 192.82 million. The worldwide death toll went up by 8,539 to 4.14 million. The United States had the most cases at 35.15 million, up 56,525, at the most deaths at 625,808, up 416.
Thailand ranked 50th globally with its 453,132 accumulated cases.
