Kazuto Ioka stands as one of Japan’s most accomplished boxing champions, having created an incredible legacy that has inspired countless fans worldwide.
Known for his technical skill and fierce determination, Ioka has won world titles across four different weight divisions, making him the first Japanese male boxer to achieve this remarkable feat.
His journey through professional boxing has been filled with victories, setbacks, and comebacks that showcase his incredible fighting spirit.
Kazuto Ioka’s Biography
| Information | Details |
|---|---|
| Full Name | Kazuto Ioka (井岡一翔) |
| Date of Birth | March 24, 1989 |
| Age | 36 years old |
| Education | Tokyo Agricultural University |
| Nationality | Japanese |
| Height | 5’4½” (164 cm) |
| Weight | 115 lbs (52 kg) |
| Turned Professional | April 12, 2009 |
| Net Worth | $4 million |
| Career Earnings | $300,000 |
| Marital Status | Divorced (married twice) |
| Instagram Profile | N/A |
| Twitter Profile | N/A |
Early Career
Kazuto Ioka’s journey into boxing began during his childhood when he was deeply inspired by watching his uncle, Hiroki Ioka, who was a two-time world champion. The turning point came when nine-year-old Kazuto watched his uncle lose a world title fight in 1998, which brought him to tears and sparked his determination to follow in his uncle’s footsteps.
His father, Kazunori Ioka, who was also a former professional boxer, began training him when he was twelve years old.
During his amateur career, Ioka built an impressive record of 95 wins and 10 losses. He dominated the Japanese amateur scene by winning six national high school tournaments, showcasing his exceptional talent from an early age.
His amateur achievements included multiple victories at the All Japan Selected High School Boxing Championships and National Sports Festival tournaments. However, his Olympic dreams were dashed in 2008 when he failed to qualify for the Beijing Olympics after losing to Amnat Ruenroeng in the semifinals of the King’s Cup tournament.
This disappointment led him to make a life-changing decision – he dropped out of Tokyo Agricultural University and turned professional in 2009, just before his 20th birthday.
Professional Career
Ioka made his professional debut on April 12, 2009, defeating Thongthailek Sor Tanapinyo via third-round technical knockout. His rise through the professional ranks was nothing short of meteoric.
In just his seventh professional fight, he captured his first world title by defeating Oleydong Sithsamerchai for the WBC minimumweight championship in February 2011. This victory made him one of the youngest world champions in Japanese boxing history.
His career reached new heights when he unified the WBC and WBA minimumweight titles by defeating compatriot Akira Yaegashi in June 2012. This historic bout marked the first unification fight between two Japanese fighters. Ioka continued his dominance by moving up weight classes and capturing titles in the light flyweight and flyweight divisions.
After briefly retiring in 2017, he made a successful comeback in 2018 and eventually won the WBO super flyweight title in 2019, becoming the first Japanese male boxer to win world championships in four different weight divisions.
His most recent significant fights include battles against Fernando Martinez, where he lost his WBA super flyweight title in July 2024 and again in their rematch in May 2025.
Kazuto Ioka’s Net Worth Details
As of 2026, Kazuto Ioka’s estimated net worth is approximately $4 million.
Fight Purses
| Date | Opponent | Event / Title | Result | Estimated Purse |
|---|---|---|---|---|
| Dec 31, 2023 | Josber Perez | WBA Super Flyweight Title | Win (UD) | $400,000 |
| Jun 24, 2023 | Joshua Franco (Rematch) | WBA Super Flyweight Title | Win (UD) | $500,000 |
| Dec 31, 2022 | Joshua Franco | WBA & WBO Title Unification | Draw | $350,000 |
| Jul 13, 2022 | Donnie Nietes (Rematch) | WBO Super Flyweight Title | Win (UD) | $350,000 |
| Dec 31, 2021 | Ryoji Fukunaga | WBO Super Flyweight Title Defense | Win (UD) | $300,000 |
| Sep 1, 2021 | Francisco Rodriguez Jr. | WBO Super Flyweight Title | Win (UD) | $300,000 |
| Dec 31, 2020 | Kosei Tanaka | WBO Super Flyweight Title Defense | Win (TKO) | $500,000 |
| Dec 31, 2019 | Jeyvier Cintron | WBO Super Flyweight Title Defense | Win (SD) | $250,000 |
| Jun 19, 2019 | Aston Palicte | Vacant WBO Super Flyweight Title | Win (TKO) | $200,000 |
| Dec 31, 2018 | Donnie Nietes | Vacant WBO Super Flyweight Title | Loss (SD) | $180,000 |
| Sep 8, 2018 | McWilliams Arroyo | Comeback Fight | Win (UD) | $100,000 |
Career Earnings
| Date | Opponent | Fight Type / Title | Purse (Reported/Estimated) |
|---|---|---|---|
| Jul 7, 2024 | Fernando Martínez | IBF unification fight | $300,000 |
| Dec 31, 2023 | Josber Perez | WBA Super-Fly Title Defense | ~$425,000 |
| Jun 24, 2023 | Joshua Franco (rematch) | WBA Super-Fly Title | $350,000 |
| Dec 31, 2022 | Joshua Franco | Unification WBA/WBO (Majority Draw) | $350,000 |
| Previous fights | – | Recent Japan / NYE bouts | $200,000–$350,000 each |
Career Stats
| Statistic | Details |
|---|---|
| Total Fights | 36 |
| Wins | 31 |
| Losses | 4 |
| Draws | 1 |
| Knockouts | 16 |
| KO Percentage | 44.4% |
| Professional Debut | April 12, 2009 |
| Stance | Orthodox |
| Total Rounds | 343 |
| Average Fight Length | 9.5 rounds |
| World Titles Won | 6 (across 4 weight divisions) |
| Title Defenses | 17 |
| Current Ranking | #2 by The Ring Magazine (Super Flyweight) |
FAQs
1. How many world titles has Kazuto Ioka won across weight divisions?
Kazuto Ioka has won world championships in four weight divisions: minimumweight (105 lbs), light flyweight (108 lbs), flyweight (112 lbs), and super flyweight (115 lbs). He made history as the first Japanese male boxer to achieve this four-division feat, capturing titles from WBC, WBA, IBF, and WBO organizations throughout his career.
2. What inspired Ioka to pursue boxing professionally?
Ioka was inspired by his uncle Hiroki Ioka, a two-time world champion. At nine years old, he watched Hiroki lose a 1998 title fight, which moved him to tears and sparked his boxing journey. His father Kazunori Ioka, also a former boxer, began training him at age twelve, nurturing his early talent.
3. Why did Ioka retire and return to boxing?
Ioka retired on December 31, 2017, citing satisfaction with his three-division titles and his marriage to singer Nana Tanimura. Tensions with his father-trainer also contributed. He returned in 2018 after attending a boxing event reignited his passion, leading to a comeback fight against McWilliams Arroyo that September.
4. What were the outcomes of Ioka’s fights against Fernando Martinez?
Ioka lost both bouts to Fernando Martinez. Martinez won a controversial unanimous decision to unify the WBA and IBF super flyweight titles. Their May 2025 rematch saw Martinez win again by UD despite Ioka scoring a tenth-round knockdown, ending with judges favoring Martinez 114–113, 115–112, and 117–110.
5. Has Kazuto Ioka ever been knocked out in his professional career?
Ioka has never been knocked out in his 36-fight career. All four losses—to Amnat Ruenroeng (2014), Donnie Nietes (2018), and Fernando Martinez twice (2024, 2025)—were by decision. His durability remains a hallmark, with 343 career rounds showcasing his resilience against elite opponents.
