Igor Tanabe was born on May 9, 2000, in São Paulo, Brazil, into a family rooted in the city's substantial Brazilian-Japanese community — one of the largest outside Japan. In January 2004, the Tanabes relocated to Japan, where Igor spent the formative years that shaped him as both a person and an athlete. Like many children raised in Japan, he gravitated toward football (soccer) as his primary competitive outlet through much of his childhood.

The path that would define his life opened in 2007, during a school holiday, when Igor and his father visited a local jiu-jitsu gym where his uncle trained. His uncle invited them onto the mats, and that single session sparked an immediate connection with grappling. The experience resonated with the whole family, and the Tanabes became regular members of the academy run by Gabriel Shibuya. It was within that environment that Igor first crossed paths with Ingrid Franco, a fellow student in the children's classes — a meeting that would eventually lead to marriage, weaving the personal and the athletic into a single thread throughout his career.

Igor Tanabe's development as a jiu-jitsu practitioner unfolded through a small, tightly connected circle of coaches whose influence spanned his entire career. His foundational training took place under Gabriel Shibuya, but when Shibuya relocated to Brazil, responsibility for Tanabe's technical education passed to his father, Rafael Guimarães, and his future father-in-law, Walter Lima Franco — an arrangement that reflected the uniquely personal nature of his BJJ journey.

This father-and-father-in-law coaching duo guided Tanabe through his blue and purple belt stages, the period during which he first attracted international attention as one of the most promising grappling prospects of his generation. During frequent trips to the United States for competition, Igor cultivated a close friendship with Eduardo Telles at Nine-Nine Jiu-Jitsu Academy (99 BJJ), a relationship that grew into a formal coaching partnership. Together, Walter Franco and Eduardo Telles promoted Tanabe to both his brown and black belts, with the black belt ceremony taking place in May 2020 — a milestone that formalized what his competitive record had long suggested. Tanabe represents 99Academy in competitive jiu-jitsu, with an additional affiliation to Igloo BJJ.

Few grapplers of Tanabe's generation assembled a colored belt résumé as comprehensive as the one he built competing primarily out of Japan on the IBJJF circuit. His success across juvenile, blue, purple, and brown belt divisions — spread across multiple continents — placed him in rare company among his peers.

Juvenile and Blue Belt Dominance

His juvenile career laid the foundation. In 2016, he claimed gold at both the IBJJF European Open Juvenile and the IBJJF Asian Open Juvenile, adding silver medals at the World Championship Juvenile, the Pan Championship Juvenile, the European Open Juvenile, and a bronze at the Asian Open Juvenile that same year. In 2017, he captured gold at the 2017 IBJJF World Championship (blue belt, juvenile division) and gold at the 2017 IBJJF Pan Championship (juvenile), alongside a silver at the 2017 IBJJF European Open (purple belt) and additional silver and bronze medals at the Worlds and Pans in the juvenile categories.

Purple and Brown Belt Excellence

At purple belt, Tanabe's results moved from impressive to exceptional. In 2018, he captured double gold at the IBJJF World Championship — winning both the gi and no-gi formats — a rare demonstration of versatility across rule sets. That same year he added an Asian Open title at purple belt, having already secured a European Open gold in 2017. His brown belt campaign continued the upward trajectory, with an Asian Open title in 2019 and a bronze at the World Championship. After receiving his black belt in May 2020, he immediately asserted himself at the highest domestic level, claiming back-to-back IBJJF All Japan Championship titles in 2020 and 2021.

The COVID-19 pandemic fundamentally altered the competitive landscape for grapplers based in Japan, halting international events and sharply reducing domestic opportunities. For Tanabe, the timing coincided with a pivotal personal moment: his wife was pregnant with their first child, and the financial unpredictability of a jiu-jitsu competition career felt increasingly difficult to sustain. His decision to pivot to MMA carried characteristic directness — he told his wife, "Relax, I'll fight MMA" — reflecting both pragmatism and confidence in his ability to transfer elite grappling skills to the cage.

Early Finishes and Breakthrough Performances

His professional MMA debut came in October 2021 at HEAT 49 in Nagoya, Japan, where he submitted Hiroyuki Shimizu in under one minute — an immediate statement of intent. Just over a year later, at INOKI BOM-BA-YE 2022 in December 2022, Tanabe delivered arguably the most high-profile result of his early MMA career, submitting combat sports veteran Melvin Manhoef via heel hook in under two minutes at light heavyweight, bringing his name to a significantly wider international audience.

Establishing Himself in RIZIN

Tanabe sustained that momentum through 2023, defeating Daichi Abe by heel hook in a RIZIN middleweight bout in July 2023, then submitting Koji Shikuwa in October 2023 to advance his record to 4-0. The year closed on his most prominent platform yet: headlining RIZIN 45 on December 31, 2023, where he submitted UFC veteran Shinsho Anzai by first-round choke at welterweight to bring his professional record to 5-0, marking three consecutive first-round finishes under the RIZIN banner. Having competed across welterweight, middleweight, and light heavyweight, Tanabe expressed in December 2023 his ambition to compete at least four times in 2024 and his desire to help build RIZIN's 170-pound division toward a welterweight title.

On December 28, 2024 (Japan time), RIZIN Fighting Federation announced that an MRI performed in early December 2024 confirmed Igor Tanabe's diagnosis with moyamoya disease — a rare and progressive cerebrovascular disorder that restricts blood flow to the brain. RIZIN cited the risks associated with head impacts and the severe dehydration inherent in competitive weight cutting as the reasons for Tanabe stepping away from MMA competition for an indefinite period.

Tanabe responded publicly with the same resolve that had defined his competitive career: "It is said that there is no cure for moyamoya disease, but I have made the impossible possible. I will definitely recover and fight in front of you all again."

Rather than withdrawing from athletic competition entirely, Tanabe chose a path that balanced his drive to compete with the realities of his diagnosis. In early 2025, he announced a return to competitive grappling — a discipline where the physical risks associated with his condition are considerably reduced compared to the demands of MMA. The decision reflects both a pragmatic awareness of his health circumstances and an enduring competitive identity rooted in the sport that first defined him. For an athlete whose entire journey began on a mat in Japan as a child, the return to grappling carries a significance that extends well beyond strategy.