There were record highs of 165 Covid-19 fatalities and 17,669 new cases over the past 24 hours, the Public Health Ministry reported on Thursday morning.
There were 17,408 cases in the general population and 261 among prison inmates.
Since April 1, when the third wave of Covid-19 began, there have been 532,167 Covid-19 patients, 352,864 of whom have recovered.
Since the pandemic started early last year, there have been 561,030 Covid-19 cases, 370,492 of whom recovered.
The death toll was at 4,468 in the third wave and 4,562 from the beginning of the pandemic early last year.
The previous high of daily Covid-19 fatalities was 141 was reported on July 17. The previous daily record of 16,533 infections was reported on Wednesday.
The Centre for Covid-19 Situation Administration (CCSA) reported on Thursday afternoon that more than half of the fatalities were registered in Bangkok and five neighbouring provinces.
The capital logged 58 deaths, while Samut Prakan reported 32 fatalities, according to the CCSA. Pathum Thani had 17 deaths, Nonthaburi nine, Samut Sakhon six and Nakhon Pathom five.
Bangkok led new transmissions with 3,963 cases, followed by Samut Sakhon (1,172), Nakhon Pathom (984), Chon Buri (982) and Samut Prakan (810).
There were 17 infections coming from abroad, six of them Thai nationals returning from Myanmar and four Thais from Malaysia.
The rest were foreign nationals arriving from Russia, the United States, Columbia, the United Kingdom and Myanmar.