It will be the day’s first bout at the Kokugikan Arena and is scheduled to start at noon, Bangkok time.
Sudaporn, 29, lost 3-2 to the 31-year-old Dubliner in the 2018 world championships final.
At stake is a place in the final as the winner will be assured of at least a silver and vie for gold, while the loser will return home with a bronze.
To beat the opponent, the Thai probably needs her best form as Harrington is the top seed and considered favourite to win gold.
Sudaporn appears to be Thailand’s only hope to join taekwondo champion Panipak Wongpattanakit as the country’s gold medallists at Tokyo 2020.
Golfers Patty Tavatanakit and Ariya Jutanugarn have a mountain to climb to claim gold in the women’s competition.
While Patty, whose Thai name is Paphangkorn, was five shots off the pace after yesterday’s opening round, Ariya was tied for 58th in the 60-player field.
But Sudaporn is cautious about her chances of claiming gold.
“I don’t know if I will be able to go the distance and win the gold. At this point, I will take it one fight at a time,” Sudaporn said after her quarter-final victory on Tuesday.
With that win, the Udon Thani native has become the country’s only second medallist at Tokyo and first ever female boxer to claim an Olympic medal.
Thailand coach Kamanit Nareesak said Sudaporn has watched tapes of Harrington’s fights several times and sparred with teammates Jutamas Jitpong and Baison Manikon.
Kamanit described Harrington as an intelligent boxer.
“She has a high IQ and moves fast,” the coach said. “Sudaporn would have to change her rhythm to counter her style.”
Already a millionaire with an Olympic bronze medallist, Sudaporn will get much richer if she advances to the final and ultimately secures gold.
Under the National Sports Development’s bonus scheme, an Olympic champion will receive B12 million, a silver winner B7.2mn and a bronze medallist B4.8mn.
Bangchak and its allies will give cash to a medal winning Thai boxer - B10mn for gold, B3mn for silver and B2mn for bronze.
Also the National Olympic Committee of Thailand gives an Olympic medal winner a monthly salary for 20 years with a gold medallist receiving B12,000, a silver medallist B10,000 and a bronze medallist B8,000.