Mexico’s undefeated women’s flyweight “Kill Bill” Regina Tarin has officially signed with the UFC and will make her promotional debut on Saturday, February 28, 2026, at UFC Mexico in Arena CDMX, Mexico City. The 21‑year‑old steps in on short notice to replace Sofia Montenegro, who withdrew from a scheduled women’s flyweight bout with Lithuanian opponent Ernesta “Heavy‑Handed” Kareckaite for reasons not disclosed.
“Kill Bill” Regina Tarin Makes UFC Debut Against Ernesta Kareckaite in Mexico City
The matchup will now be contested at a 130‑pound catchweight, a change first reported by Marcel Dorff of Eurosport. Tarin holds a perfect 7–0 professional record, with all of her wins coming by finish except a 2024 unanimous‑decision victory over Andrea Garcia. Four of her seven wins have come via knockout, and the majority of those finishes occurred inside the first round, which is part of why she has drawn attention as a rising Mexican talent.
Tarin’s last outing was in November 2025 at Tough N Xtreme 1125 in Costa Rica, where she knocked out Yurivia Jimenez just over two minutes into their co‑main event encounter. Earlier in 2024, she claimed the vacant Budo Sento Championship women’s bantamweight title with a fourth‑round TKO of Luisa Cifuentes, adding a regional belt to her growing resume. She also owns a stoppage win over Kaytlin Neil, a former contestant on Season 30 of The Ultimate Fighter, during a Combate Global appearance in 2024.
Her opportunity against Kareckaite comes at a busy time in her career. Tarin had been scheduled to compete in a Muay Thai bout at Budo Sento Championship 33 this week before being called to the UFC, and she previously spent several days at the WWE Performance Center in January 2026 for a tryout. Public reports note she was the only Mexican woman invited to that particular WWE training session, highlighting interest in her from beyond the MMA world.
Kareckaite, a 27‑year‑old from Lithuania, carries a 6–1–1 record and is 1–1 inside the Octagon so far. She earned her UFC contract through Dana White’s Contender Series in 2023 with a split‑decision win over Carli Judice, then went on to defeat Nicolle Caliari via split decision in January 2025. Her UFC debut was a loss to former title‑hopeful Dione Barbosa by unanimous decision at UFC 301.
Regina Tarin has framed the fight as a major milestone, writing on Instagram that “Los planes de Dios son perfectos y a la gente buena le pasan cosas buenas siempre” and calling Saturday her UFC debut moment in Mexico. As one of several Mexican fighters on the card, she will look to start her UFC journey with a strong statement inside the first 130‑pound contest of her career.
