McWilliams Arroyo has four losses against four opponents on his boxing record. For a list of Arroyo's best fights, refer to "Best fights of McWilliams Arroyo".
On September 8, 2018 McWilliams Arroyo faced off against Kazuto Ioka in a super-flyweight bout at age 32. He was coming in with a record of 17-4 (14), and Ioka was 29 years old and with a record of 22-1 (13). Arroyo lost the fight via 10-round unanimous decision.
On April 23, 2016 McWilliams Arroyo fought Román González in a flyweight world-title fight for González' WBC and The Ring titles. Arroyo was 30 years old and with a record of 16-3 (14), and González was 28 years old and with a record of 44-0 (38). Arroyo lost the fight via 12-round unanimous decision.
On September 10, 2014 McWilliams Arroyo fought Amnat Ruenroeng in a flyweight world-title fight for Ruenroeng's IBF title. Arroyo was 28 years old and with a record of 15-2 (13), and Ruenroeng was 34 years old and with a record of 13-0 (5). Arroyo lost the fight via 12-round split decision.
On June 12, 2010 McWilliams Arroyo faced off against Takashi Okada at age 24. He was coming in with a record of 3-1 (3). Arroyo lost the fight via 4-round unanimous decision.
