On September 8, 2018, a 32-year-old McWilliams Arroyo (17-3, 14 KOs) and a 29-year-old Japanese boxer Kazuto Ioka (22-1, 13 KOs) met in the ring in a super-flyweight bout.
Arroyo came in to the fight on a 1-fight win streak with a 70% KO rate, and was fighting after a gap of 6 months and 15 days. Ioka was on a 8-fight win streak with a 56% KO rate, and fighting after a layoff of 1 year, 4 months, and 16 days.
Kazuto Ioka defeated McWilliams Arroyo via unanimous decision in the 10-round super-flyweight fight. Ioka improves his record to 23-1, while Arroyo adds a loss to his record at 17-4.
On April 23, 2016, a 30-year-old McWilliams Arroyo (16-2, 14 KOs) got a shot at the flyweight WBC and The Ring title held by 28-year-old Nicaraguan boxer Román González (44-0, 38 KOs).
Arroyo came in to the fight on a 1-fight win streak with a 77% KO rate, and was fighting after a gap of 1 year and 12 days. González was on a 44-fight win streak with a 86% KO rate, and fighting after a layoff of 6 months and 6 days.
Román González defeated McWilliams Arroyo via unanimous decision and successfully defended his WBC and The Ring flyweight titles. González improves his record to 45-0, while Arroyo adds a loss to his record at 16-3.
On September 10, 2014, a 28-year-old McWilliams Arroyo (15-1, 13 KOs) got a shot at the flyweight IBF title held by 34-year-old Thai boxer Amnat Ruenroeng (13-0, 5 KOs).
Arroyo came in to the fight on a 12-fight win streak with a 81% KO rate, and was fighting after a gap of 2 months and 22 days. Ruenroeng was on a 13-fight win streak with a 38% KO rate, and fighting after a layoff of 4 months and 3 days.
Amnat Ruenroeng defeated McWilliams Arroyo via split decision and successfully defended his IBF flyweight title. Ruenroeng improves his record to 14-0, while Arroyo adds a loss to his record at 15-2.
On June 12, 2010, a 24-year-old McWilliams Arroyo (3-0, 3 KOs) and Takashi Okada met in the ring.
Arroyo came in to the fight on a 3-fight win streak with a 100% KO rate, and was fighting after a gap of 14 days.
McWilliams Arroyo lost to Takashi Okada via unanimous decision in the 4-round fight, and adds an loss to his record at 3-1.