Nickname
“Baby Shark” — originated from a friend’s joke during an Abu Dhabi competition, which stuck due to his small stature paired with dangerous grappling skill
Date of Birth
March 20, 2002
Birthplace
Manaus, Amazonas, Brazil
Belt
Black Belt (awarded December 13, 2020, by Melqui Galvão — just seven months after his brown belt promotion, at age 18)
Belt Lineage
Carlos Gracie → Hélio Gracie → Royler Gracie / Rolker Gracie → Augusto Monteiro → Ronnie Melo → Melquisedeque Galvão → Diogo Reis
Weight Class
66 kg / Light-Featherweight (also competes at 61 kg / Flyweight in ONE Championship)
Full Bio
Diogo Reis grew up in Manaus, in Brazil’s Amazonas state, in a working-class family. He discovered Brazilian Jiu-Jitsu at age 10 in 2012 after watching his older brother train under coach Alexandre Oliveira, who invited him to join. Reis progressed to yellow belt under Oliveira before, around age 15, seeking a more competitive environment. He met coach Melqui Galvão at a local tournament in 2015 and joined his academy, where he developed rapidly through the colored belts.
As a juvenile competitor, Reis completed an IBJJF Grand Slam — winning the European Open, Brazilian Nationals, Pan, and World Championships — and won back-to-back Juvenile World Championship titles in 2018 and 2019. He was promoted to black belt by Galvão on December 13, 2020, at age 18, spending less than a year at brown belt beforehand. He made his formal black belt competitive debut roughly seven months later at the Abu Dhabi Grand Slam in Rio de Janeiro in July 2021, going on to collect multiple AJP Grand Slam and Abu Dhabi World Pro results that year.
At the 2022 IBJJF World Championship, Reis reached the final before losing 2-0 to Diego “Pato” Oliveira, taking silver. Months later, at his ADCC debut in 2022, he won gold in the 66kg division alongside training partners Mica Galvão and Fabricio Andrey, who competed in the same event. He successfully defended his ADCC title at the 2024 World Championship, defeating Huaiqing Xu, Fabricio Andrey, Josh Cisneros, and Diego “Pato” Oliveira to become a two-time 66kg World Champion, finishing the final with a body-lock pass into an arm-triangle choke.
Beyond IBJJF and ADCC competition, Reis built a significant profile on the professional superfight circuit. He won the Who’s Number One (WNO) featherweight title in October 2023 via a four-man tournament, but lost the belt in his first defense against Diego “Pato” Oliveira at WNO 21 after suffering an injury during the match. He also picked up superfight wins over Jack Sear (Honor Submission Challenge Italy, 2023), Samuel Nagai (BJJ Stars 11, 2023), Felipe Machado (BJJ Stars 13, 2024), and Cleber Sousa (Majestic BJJ Challenge 5, 2025), and returned to the WNO stage against Shay Montague after recovering from injury.
In 2024, Reis signed with ONE Championship, expanding into a global mainstream combat sports platform. He made his promotional debut at ONE Fight Night 29 in Bangkok on March 7, 2025, submitting Shoya Ishiguro by kimura in the first round (weighing in over the flyweight limit and being fined as a result). Later that year he earned a shot at the vacant ONE Flyweight Submission Grappling World Championship, facing Daiki Yonekura at ONE Fight Night 38 on December 5, 2025, and winning the title. He also collected further IBJJF medals in 2025, including gold at the European Championship and silver at the Pan Championship in the light-featherweight division.
Achievements
- ONE Championship Flyweight Submission Grappling World Champion (2025)
- 2x ADCC World Championship gold medalist, 66kg division (2022, 2024)
- IBJJF Grand Slam winner — juvenile/colored belt divisions (2019)
- 2x IBJJF Juvenile World Champion (2018, 2019)
- Who’s Number One (WNO) Featherweight Champion (2023)
- IBJJF European Championship gold medalist, light-featherweight (2025)
- IBJJF World Championship silver medalist, black belt (2022)
- ONE Submission Grappler of the Year (2025)