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Super featherweight · Japan

Kai Watanabe

18-3-1 11 KO · 2021–2026

Kai Watanabe is a super featherweight boxer from Japan. Record 18-3-1 with 11 knockouts over 2021–2026. Kai Watanabe last fought Rentaro Kimura on Sep 8, 2026 and won by TKO in round 2 of 8.

Also: 渡邊海
Born—
Country🇯🇵 Japan
DebutApr 21, 2021
Career2021–2026
Rounds boxed99
KO share61%
TitlesWBO Asia Pacific super featherweight title 2025
Boxerbook rating#29 in Super featherweight · 1671 ± 135Why here ›
Confirmed bouts22 of 22 · 22 official

Record and next fight

Record
18-3-1, 11 KOs · 2021–2026
Next fight
No next fight confirmed

Last result

W
Rentaro Kimura 🇯🇵
TKO 2/8 · Korakuen Hall, 🇯🇵
2026-09-08 ›
official ★

The record

22 bouts, 2021–2026, newest first. Records under each bout are both boxers going in.

Bouts by source: Japan Boxing Commission — 試合報告書 · 22, Wikipedia (ja) · 21

W
Rentaro Kimura 🇯🇵
TKO 2/8 · Korakuen Hall, 🇯🇵
Watanabe 17-3-1 · Kimura —
2026-09-08 ›
official ★
W
Hideto Hideo
UD 8/8 · Korakuen Hall, 🇯🇵
Watanabe 16-3-1 · Hideo —
2026-05-12 ›
official ★
W
Shido Arai
TKO 6/8 · Korakuen Hall, 🇯🇵
Watanabe 15-3-1 · Arai —
2026-02-19 ›
official ★
W
Surasak Chamkao
TKO 8/8 · Korakuen Hall, 🇯🇵
Watanabe 14-3-1 · Chamkao —
2025-11-27 ›
official ★
L
Reo Saito 🇯🇵
Lost WBO Asia Pacific title
TKO 3/12 · Korakuen Hall, 🇯🇵
Watanabe 14-2-1 · Saito —
2025-07-31 ›
official ★
W
Ryusei Ishii
Vacant WBO Asia Pacific super featherweight title
TKO 7/12 · Korakuen Hall, 🇯🇵
Watanabe 13-2-1 · Ishii —
2025-04-22 ›
official ★
L
Tsubasa Narai 🇯🇵
SD 10/10 · Ariake Arena, 🇯🇵
Watanabe 13-1-1 · Narai —
2025-01-24 ›
official ★
W
Toshihiro Suzuki 🇯🇵
Vacant WBO Asia Pacific super featherweight title
KO 1/12 · Korakuen Hall, 🇯🇵
Watanabe 12-1-1 · Suzuki 5-0-0
2024-08-22 ›
official ★
W
Shunpei Oohata
Japanese youth title, 1st defence
MD 8/8 · Korakuen Hall, 🇯🇵
Watanabe 11-1-1 · Oohata —
2024-03-08 ›
official ★
W
Shinsei Otani
Vacant Japanese youth super featherweight title
MD 8/8 · Korakuen Hall, 🇯🇵
Watanabe 10-1-1 · Otani —
2023-11-27 ›
official ★
W
John John Estrada
KO 1/8 · Esforta Arena Hachioji, 🇯🇵
Watanabe 9-1-1 · Estrada —
2023-07-08 ›
official ★
L
Hiroki Hanabusa 🇯🇵
Japanese youth title, 2nd defence, later vacated
SD 8/8 · Uchinada Town General Gymnasium, 🇯🇵
Watanabe 9-0-1 · Hanabusa 10-2-4
2023-03-19 ›
official ★
W
Ryō Nakai 🇯🇵
TKO 2/8 · Ota Ward General Gymnasium, 🇯🇵
Watanabe 8-0-1 · Nakai —
2022-12-31 ›
official ★
W
Detchadeen Sornsirisparthin
TKO 4/6 · Korakuen Hall, 🇯🇵
Watanabe 7-0-1 · Sornsirisparthin —
2022-08-30 ›
official ★
W
Ryota Ishida
TKO 1/6 · Korakuen Hall, 🇯🇵
Watanabe 6-0-1 · Ishida —
2022-04-26 ›
official ★
D
Chihiro Iwashita
MD 4/4 · Korakuen Hall, 🇯🇵
Watanabe 6-0-0 · Iwashita —
2022-02-06 ›
official ★
W
Ryo Yoshida
TKO 1/5 · Korakuen Hall, 🇯🇵
Watanabe 5-0-0 · Yoshida —
2021-12-19 ›
official ★
W
Seiji Nunozaki
UD 4/4 · Korakuen Hall, 🇯🇵
Watanabe 4-0-0 · Nunozaki —
2021-11-03 ›
official ★
W
Yuya Hirose
UD 4/4 · Korakuen Hall, 🇯🇵
Watanabe 3-0-0 · Hirose —
2021-09-27 ›
official ★
W
Ren Kakimoto
UD 4/4 · Hachioji City Fujimori Gymnasium, 🇯🇵
Watanabe 2-0-0 · Kakimoto —
2021-07-17 ›
official ★
Show all 22 bouts
W
Soshi Hattori
TKO 1/4 · Korakuen Hall, 🇯🇵
Watanabe 1-0-0 · Hattori —
2021-06-05 ›
official ★
W
Hikari Sato
UD 4/4 · Korakuen Hall, 🇯🇵
Watanabe 0-0-0 · Sato —
2021-04-21 ›
official ★

Ratings now

Not in any current ranking.

World titles

No world title reigns recorded.

Facts

What is Kai Watanabe's record?
Kai Watanabe's professional record is 18-3-1 with 11 knockouts.
When is Kai Watanabe's next fight?
No next fight is confirmed as of 17 Oct 2026.
Who did Kai Watanabe fight last?
Kai Watanabe last fought Rentaro Kimura on Sep 8, 2026 and won by TKO in round 2 of 8.

Sources

Boxerbook ID 20606 · permanent link boxerbook.com/id/20606. Wikidata (CC0), English Wikipedia (CC BY-SA), photo from the Instagram profile. Last fetched: 2026-10-12. Spot a mistake? Every bout page has a link to report it.

Wikidata ↗Instagram ↗