There were 6,978 new Covid-19 cases and 62 more fatalities registered during the previous 24 hours, the Public Health Ministry reported on Wednesday morning.
There were 6,632 cases in the general population and 346 among prison inmates.
The number of new cases rose from 6,904 announced on Tuesday, when the country recorded 61 more deaths.
On Tuesday, 7,697 Covid-19 patients were discharged from hospitals after recovering from the coronavirus.
Since April 1, when the third wave of Covid-19 began, Thailand has treated 1,960,610 Covid-19 patients, 1,845,758 of whom have recovered to date.
Since the pandemic started early last year, there have been 1,989,473 Covid-19 cases, with 1,873,184 complete recoveries so far.
The death toll stood at 19,732 during the third wave and 19,826 since the beginning of the pandemic.
Sumanee Wacharasin, hazard communication director of the Department of Disease Control, said the 62 latest fatalities were aged 9 to 102 years and included four Myanmar nationals. Two were children, aged 9 in Songkhla and 13 in Tak.
Bangkok recorded five new deaths while a further three were reported in the adjacent province of Samut Prakan.
Other central plain provinces further from the capital recorded 16 more deaths - in Ratchaburi (5), Phetchaburi (3), Saraburi (2), Kanchanaburi (2), Prachin Buri (1), Chanthaburi (1), Suphan Buri (1) and Ayutthaya (1).
The Northeast had nine fatalities - in Chaiyaphum (4), Si Sa Ket (2), Ubon Ratchathani (1), Amnat Charoen (1) and Yasothon (1).
The South reported 23 more deaths – in Songkhla (5), Nakhon Si Thammarat (5), Yala (2), Pattani (2), Satun (2), Trang (2), Phatthalung (3), Krabi (1) and Narathiwat (1).
The North saw six fatalities – in Tak (4), Chiang Rai (1) and Sukhothai (1).
The 6,978 new cases included 6,624 local infections and eight imported cases. Of the local infections, 6,387 were confirmed at hospitals and 237 via mass testing.
Bangkok had 864 new cases, followed by 479 in Songkhla, 380 in Chiang Mai, 356 in Pattani, 233 in Samut Prakan, 224 in Nakhon Si Thammarat, 203 in Chon Buri, 202 in Yala, 192 in Narathiwat and 183 in Surat Thani.
“New caseloads nationwide are noticeably declining,” Dr Sumanee said.
However, she said clusters from markets continued and included 310 new cases in Bangkok, 53 in Chiang Mai, 29 in Chon Buri, 13 in Prachuap Khiri Khan, 11 in Sa Kaeo and five in Kanchanaburi.
New cases in prisons included 161 in Nakhon Ratchasima and 92 in Bangkok.
The eight imported cases were from Russia (1), Germany (1), the Netherlands (1), India (1), Cambodia (3) and Myanmar (1).
On Tuesday 96,463 people received Covid-19 treatment at hospitals (down from 97,244), including 1,877 seriously ill patients (down from 1,898) and 423 dependent on ventilators (up from 417).
Global Covid-19 cases rose by 458,142 in 24 hours to 251.56 million. The worldwide death toll went up by 7,619 to 5.08 million.
The United States had the most cases at 47.54 million, up 72,358, and the most deaths at 778,316, up 1,339.