Thanongsak Simsri defends the IBF junior flyweight title against Mark Vicelles on Saturday, September 26, from Fujisanmesse at the foot of Mount Fuji in Japan.
Simsri (40-1, 35 KOs) is Thailand’s only current world titleholder and is making his second defense of the belt. Vicelles (21-2-1, 11 KOs), a 30-year-old southpaw with a decade of pro experience, gets his second world title opportunity after losing an IBF eliminator to Regie Suganob in 2023.
What’s At Stake
- The bigger picture: Simsri wants to eventually unify the 108-pound division, calling this fight “another crucial one” in that push.
- The mandatory clock: Simsri must face IBF mandatory challenger Regie Suganob by January 13, 2027, unless a unification bout supersedes the obligation.
- The challenger’s path back: Vicelles was stopped by Kosuke Tomioka at flyweight last September but rebounded with a win over Carlo Diaz earlier this year to earn this shot.
Full Fight Card
| Bout | Stakes |
|---|---|
| Thanongsak Simsri (c) vs. Mark Vicelles | IBF Junior Flyweight Title |
Additional bouts on the card had not been finalized at the time of publishing. Check back for updates.
Simsri said he “won’t let my guard down for even a split second” against a fighter he called dangerous on the counter.
How To Watch
- Date/Time: Saturday, September 26, 2026, morning ET (US broadcast time not yet confirmed)
- Venue: Fujisanmesse, Fuji, Japan
BoxingWire will publish a living results post once the card is underway. See the full weekend boxing schedule for every card BoxingWire is covering.
