Nonito Donaire Sr. ,with 20 years of coaching experience, has helped many professional boxers to become world champions, which include his two sons, Glenn Donaire and Nonito Donaire Jr. He worked with Michael Katsidis as his cutman. He was the head coach of the 2000 Northern California National USA Championship in Colorado Spring. He trained Nonito Donaire Jr. and Glenn Donaire from their amateur to professional career. In 2000, Sr. took his sons to the olympic trial championship. He trained and prepared Marvin Sonsona for his WBO super flyweight championship, in Toronto, Canada against Jose Lopez. Under Donaire Sr. guidance, Marvin Sonsona won by unanimous decision. He also prepared Anna Julaton for her first world championship belt.