Thamires Monteiro

Thamires Arruda Monteiro was born on January 8, 1998, in Vila Mariana, São Paulo, and grew up in Mogi das Cruzes, São Paulo, Brazil. As a child, she showed no particular inclination toward athletics, though early forays into dancing and swimming during her teenage years built a foundational body awareness that would later serve her well on the mats.

Her introduction to Brazilian Jiu-Jitsu arrived not through personal ambition but through loyalty. In late 2014, at the age of 16, Thamires stepped onto the mats for the first time at a local gym in her home region — intending simply to accompany a close friend. That social gesture quickly became something far more significant. She fell in love with the sport almost immediately and made the decision to pursue it not as a hobby but as a professional career, a commitment that would define everything that followed.

Building the Foundation Under Leandro Lo

Seeking a higher level of instruction and competition, Thamires joined New School Brotherhood under the guidance of Leandro Lo, one of the most celebrated competitors in the history of the sport. Under Lo's tutelage, she developed with remarkable speed, earning her purple belt in 2017 — less than three years after first stepping onto the mats.

International Exposure and the Move to Checkmat

Her journey then took an international turn. During her travels to the United States, Thamires trained with Atos in San Diego, California, an experience that broadened her competitive exposure and deepened her understanding of high-level jiu-jitsu. She eventually settled at Checkmat La Habra Academy under coach Lucas Leite, joining her husband, Jackson Douglas, at the team.

Reaching the Upper Ranks

Leite's mentorship proved transformative. Following a gold medal performance at the IBJJF Pan American Championships in the gi in late 2020 — her first major tournament back after the pandemic hiatus — Thamires received her brown belt promotion from Leite on the spot. She continued her ascent through the ranks, and in December 2021, Leite promoted her to black belt, marking the culmination of roughly seven years of dedicated training since she first walked into a gym as a teenager in Mogi das Cruzes.

A Top-Game Philosophy

Thamires Monteiro's competitive identity is anchored in the Pressure Passing game — a methodical, top-game-oriented approach built on physical commitment, positional control, and the gradual suffocation of an opponent's guard. This style suits her weight division, Peso Leve (64 kg / 141.5 lbs), particularly well. In a division where technical guard players depend on space and frames to create offense, the ability to impose connected, smothering weight becomes a decisive weapon.

Pressure That Transcends Weight Class

Her record across both gi and no-gi formats reflects the versatility that a consistent passing philosophy can produce. Her gold medal in the absolute division at the IBJJF American Nationals in the no-gi format in 2020 stands as a particularly telling result — executing a pressure-based approach against larger opponents demands precision and mechanical efficiency rather than reliance on physical attributes alone. Thamires demonstrated both.

The Leite Influence

Training under Lucas Leite at Checkmat La Habra Academy reinforced and refined this approach with expert precision. Leite is himself renowned for a smothering, pressure-heavy game centered on side control and top dominance, making him an ideal mentor for an athlete whose instincts already leaned in that direction. The alignment between coach and competitor created a clear, cohesive technical identity that has driven her results at the highest levels of the sport.

A Dominant Return to Competition

The period immediately following the pandemic-induced competition hiatus marked Thamires Monteiro's emergence as one of the most formidable competitors in women's jiu-jitsu. Returning to the mats in late 2020, she claimed gold at the IBJJF Pan American Championships in the gi format — a performance compelling enough to earn her the brown belt promotion from Lucas Leite on the spot.

Sustained Momentum Across Formats

She carried that momentum directly into the no-gi circuit, winning the IBJJF American Nationals in the absolute division and claiming silver at the IBJJF No-Gi Pan American Championships in 2021. Her brown belt campaign culminated with gold at the 2021 IBJJF No-Gi World Championship, establishing her unambiguously as one of the top competitors at that level. She also reached the final of the IBJJF World Championship in the gi format in 2021, finishing as runner-up and underscoring her dominance across both rulesets. A submission-only format win at the F2W SUBVERSIV Tournament in 2021 further demonstrated that her pressure-passing game translated effectively into finish-oriented competition.

Setting the Stage for Black Belt

The concentration of major results across this compressed post-pandemic window — multiple gold medals, a world championship title, and victories across gi, no-gi, and submission-only formats — identified Thamires Monteiro as an exceptional prospect ahead of her black belt debut in December 2021. The body of work she assembled at brown belt left little doubt that her ascent was far from finished.