Native of Nong Khai, a small province bordering Laos, separated by the Mekong. Suwannapheng started boxing at the age of 12 with Muay Thai, as her family had a Muay Thai gym, and she was also in her high school's boxing club. When competing in Muay Thai, she used the name "Nongbee Por.Prasith" (น้องบี ป.ประสิทธิ์) and had a record of 7 consecutive wins until she had no opponents and had to turn to amateur boxing instead. Her first amateur coach was Chartsuphong Phulad, her high school teacher.
She gradually developed skills until she was selected for the national team while she was in grade 12. Her mother still did not believe that she had become a national athlete. When she graduated, her mother had to accept her diploma instead because she was busy practicing boxing.[5]
Suwannapheng lost to AlgerianImane Khelif 0–5 in the semi-finals (round of 4). She was counted eight by the referee in the third round, giving her the bronze medal. She is the only Thai boxer to capture a medal at this Olympics.[6]
