Bence Mocsári was born without an elbow joint in his left arm. He started swimming at the age of six because of his health issues. However, when school started he gave up swimming.
Six years later, in 2012 he was watching the London Paralympic Games when he decided to become a Paralympic Champion. He began swimming again and became multiple time Para World Series medalist, Hungarian Champion and in 2017 he became fifth in 200m IM in Mexico at the World Para Swimming Championships. He was always good at running in the dry land training sessions and in 2018 his coach and the Hungarian Triathlon Union persuaded him to become a triathlete. In his first international triathlon competition which was a World Cup in Madeira (2018) he won a bronze medal.
He is now a senior in high school and his goal is to get admitted to university and to take part in the 2020 Tokyo Paralympic Games.