John Castañeda

Dana White's Contender Series Having racked up a record of 13–2, Castañeda was invited to compete at Dana White's Contender Series 5, facing Cheyden Leialoha. He won the bout via unanimous decision, but was not awarded with a contract to the UFC.

Return to Combate On October 26, 2017, it was announced that Castañeda would participate in Combate Americas' Copa Combate 2017 one-night tournament that took place on November 11, 2017. In the quarterfinals Castañeda faced Kevin Moreyra, winning by first-round submission. Advancing to the semifinals, he defeated Marc Gomez by unanimous decision. In the tournament final Castañeda faced Levy Marroquín, losing the bout via unanimous decision.

Castañeda was expected to headline Combate Americas Mexico vs. USA against Erik Pérez on October 13, 2018, but the bout was postponed to a later date because Castañeda caught staph infection.

After the tournament, Castañeda went on to lose one and win one bout in Combate Americas before being signed to the UFC on short notice.

Ultimate Fighting Championship Replacing the mourning Umar Nurmagomedov on short notice on July 26, 2020, Castañeda made his UFC debut against Nathaniel Wood at UFC on ESPN 14. He lost the fight via unanimous decision.

Castañeda faced Eddie Wineland on February 20, 2021 at UFC Fight Night 185. He won the fight via first round technical knockout.

Castañeda faced Miles Johns on February 5, 2022 at UFC Fight Night 200. He won the fight via third round technical submission.

As the last bout of his initial UFC contract, Castañeda faced Daniel Santos on October 1, 2022 at UFC Fight Night 211. This bout earned them a Fight of the Night award.

As the first fight of his new four-fight contract, Castañeda was scheduled to face Mateus Mendonça on June 3, 2023, at UFC on ESPN 46. However, Mendonça withdrew from the bout and was replaced by Muin Gafurov. Castañeda won the fight by unanimous decision.

Castañeda faced Kang Kyung-ho on November 18, 2023 at UFC 295. He won the bout via unanimous decision.

Castañeda faced Daniel Marcos on June 8, 2024, at UFC on ESPN 57. He lost the fight by unanimous decision.

Castañeda was scheduled to face Douglas Silva de Andrade on March 1, 2025 at UFC Fight Night 253. However, despite having the bout changed to a 140 pound catchweight bout, the fight was cancelled as Silva de Andrade did not have medical clearance to compete.

Replacing Jean Matsumoto, who was withdrawn from UFC 313 in order to serve as a replacement fighter two weeks prior, Castañeda was scheduled to face Chris Gutiérrez on March 8, 2025 at UFC 313 in a featherweight bout. However, a few hours before the event took place, Castañeda withdrew due to an undisclosed illness and the bout was scrapped. His bout with Gutiérrez was rescheduled to April 26, 2025 at UFC on ESPN 66. Castañeda lost the fight by split decision.

Castañeda faced promotional newcomer Mark Vologdin on April 18, 2026, at UFC Fight Night 273. Despite being slated as a bantamweight bout, it was changed to a 139-pounds catchweight bout. After Castañeda was deducted one point in the second round due to repeated groin strikes, the fight was deemed a majority draw with the judges' scorecards reading 29–27, 28–28, 28–28. 7 out of 11 media outlets scored the bout for Castañeda while the remaining four outlets scored it as a draw.

Castañeda is scheduled to face Alateng Heili on September 26, 2026 at UFC Fight Night 289.

Championships and accomplishments Mixed martial arts Ultimate Fighting Championship Fight of the Night (One time)