Jeyvier Jesús Cintrón Ocasio (born February 8, 1995) is a Puerto Rican professional boxer who challenged for the WBO junior bantamweight title in 2019.

[2][3] He was captivated by the family's trade from a young age, wearing boxing apparel to school activities, and was followed in his interest by younger brother Jeyvison.

[2][3] Feeling that it ran in the blood and that they owed a lot to the sport, Cintrón opted to become a self-professed "boxing scholar", immersing himself in the study of a variety of styles that he later tried to mimic and master.

[4] Cintrón won the 48 kg division of the 2011 junior Puerto Rico national championship, defeating Armando Mendez in the semi-finals and Jorge Cosme in the finals.

Upon returning to the Olympic village he was approached by several professional boxing scouts, among which was personnel from Golden Boy Promotions.

In December 2012, Cintrón won the silver medal at the 2012 AIBA Youth World Boxing Championships in Yerevan, Armenia.

[11][12] A change in AIBA's rules preventing boxers under the age of 19 from competing in senior tournaments directly affected Cintrón.

[4] Cintrón entered the Torneo Isaac Barrientos and won the flyweight national championship by defeating fellow Olympian Janthony Ortiz in the finals.

At the 2013 Juan Evangelista Venegas Olympic Cup, Cintrón defeated Leonardo Baez of Mexico by unanimous decision in the finals.

[16] In the qualifier for the 2014 Central American and Caribbean Games, Cintrón debuted by defeating Gerardo Cervantes of Cuba 2 rounds to one.

During the middle rounds, things turned and Ioka started throwing body punches with both hands and managed to make good work on the inside.

The punches were slowly wearing Cintron down, and even though he showed some heart in the last round, Ioka ended up the clear winner by unanimous decision.