Thanongsak Simsri

Thanongsak Simsri is a Thai light‑flyweight (junior‑flyweight, 108 lb) who has risen from domestic circuits to the world title scene. Fighting out of Thailand in an orthodox stance, the Sisaket province native stands 161 cm with a 164 cm reach. Simsri is the incumbent IBF junior‑flyweight world champion, a status he claimed by winning the vacant IBF title on June 19, 2025, and successfully defended on April 13, 2026. His professional ledger stands at 40 wins and 1 loss, with 35 stoppages. Simsri began his recorded professional career in 2018, compiling a heavy‑hitting run across Thailand and frequent appearances in Japan. Many of his early fights were staged at local venues such as Singmanassak Muaythai School and regional arenas, where he built a reputation as a stoppage-minded fighter. He captured the vacant Thai light‑flyweight title in August 2019 with a third‑round KO of Nattee Thongsingcle, and later retained Thai light‑flyweight honours in July 2021 with a third‑round TKO over Thaweesak Nakham. In March 2022 Simsri stepped up to regional honours, stopping Benjaphon Phokam in the second round to take the vacant ABF (Asian Boxing Federation) light‑flyweight title. That same year he faced his sole professional defeat, a seventh‑round TKO to Masamichi Yabuki in Yokkaichi, Japan. Simsri returned to activity with a streak of stoppages and continued to mix domestic and international assignments. Simsri's profile expanded significantly in 2024 when he won the OPBF light‑flyweight title at EDION Arena in Osaka with a unanimous decision over Miel Fajardo on April 13. He retained that regional crown twice: a fifth‑round TKO of John Paul Gabunilas in Osaka on August 4, 2024, and a split decision victory over former world‑level foe Masataka Taniguchi in Osaka on December 15, 2024. The jump to world level came in June 2025 in Tokyo, where Simsri edged Cristian Araneta by split decision to capture the vacant IBF junior‑flyweight (light‑flyweight) world title. He reinforced that standing with a second‑round TKO defense against Sergio Mendoza at Korakuen Hall in Tokyo on April 13, 2026. Throughout his career Simsri has shown a preference for finishing fights early, reflected in a high stoppage rate across 40 wins. His résumé includes domestic title success, regional championships with the ABF and OPBF, and now a recognised world title under the IBF. As the incumbent IBF junior‑flyweight champion, Simsri occupies a prominent position in the 108 lb division.