Tapia's professional boxing career began on March 25, 1988, when he fought Effren Chavez in Irvine, California.
In 1989, he won seven more fights, including a first-round knockout of Abner Barajas and an eight-round decision against John Michael Johnson.
[6] When he finally returned to the ring on March 27, 1994, he beat Jaime Olvera by a knockout in four rounds in Tulsa, Oklahoma.
He won three more fights by knockout, and then he faced Oscar Aguilar on the Michael Carbajal–Josué Camacho undercard in Phoenix for the NABF super flyweight title, winning in three rounds.
On October 12, 1994 at The Pit, Albuquerque, New Mexico, Tapia defeated Henry Martínez in eleven rounds to win the vacant WBO super flyweight title.
He retained the title with a nine-round technical draw with Ricardo Vargas and a decision in twelve against his onetime nemesis in the amateur ranks, Arthur Johnson.
In 1999, Tapia suffered his first loss in his 48-bout career, losing a decision and the WBA title to Paulie Ayala in what The Ring Magazine called its "Fight of the Year."
He became a two time world bantamweight champion by beating Jorge Eliecer Julio by a decision at Albuquerque on January 8, 2000.
In 2002, Tapia traveled to London, where he knocked out Eduardo Enrique Alvarez in the first round; after the bout, he was interviewed by former rival Romero.
He left the title vacant so he could face Lineal & The Ring champion Marco Antonio Barrera, who beat Tapia by unanimous decision.
Tapia returned on the night of October 4, 2003, defeating Carlos Contreras by ten round unanimous decision at Albuquerque.
[7] On January 17, 2007, Tapia held a press conference stating that he would face Ilido Julio on February 23 in his home town of Albuquerque, New Mexico, then retire.
[11] Tapia was scheduled to make a comeback on May 2, 2008, in El Paso, Texas, but pulled out due to contractual disputes with promoter Ron Weathers.
Tapia beat Jorge Alberto Reyes by a knockout in the 4th round on March 6, 2010, at the Ohkay Casino, San Juan Pueblo, New Mexico, United States, in front of a sold-out crowd.
Jerry Padilla, who Tapia already knew, was supposedly intrigued by the similarities in their mannerisms, and the two decided to submit to a DNA test, which proved they were father and son.