Thanongsak Simsri


Thanongsak Simsri, also known by his ring name Petchkoson Greentsuda is a Thai professional boxer who has held the International Boxing Federation light-flyweight title since June 2025. He is Thailand's 50th world boxing champion and the third to hold this weight class title in this organization, following Muangchai Kittikasem in 1989 and Saman Sorjaturong in 1995.

Early life

He was born in Sisaket province and began boxing Muay Thai at the age of 14, driven by passion for the martial art. At 19, he decided to move to Bangkok to seek new opportunities. Due to his precise and swift punching skills, he caught the attention of scouts, which led him to switch from Muay Thai to professional boxing.

Professional career

Early career

Simsri made his debut on 20 June 2018 against fellow debutant Thanapong Saekoo in Samut Prakan, Simsri won via first-round TKO.
Simsri was scheduled against the reigning WBA and The Ring light-flyweight world champion Hiroto Kyoguchi for Kyoguchi's third title defense on 3 November 2020, Simsri was at the time the eleventh-ranked contender in the WBA light-flyweight rankings. On 2 November 2020, one day before the fight, Kyoguchi announced he was unable to fight, as both he and his coaches had contracted COVID-19.

Simsri vs. Yabuki

After composing a record of 24–0, on 10 September 2022, Simsri fought former WBC light-flyweight world champion Masamichi Yabuki in what was promoted as a world title prelude for Yabuki, the fight was scheduled for a catchweight of 50 kilograms. Simsri lost the bout via seventh-round technical knockout, Yabuki knocked his opponent down twice prior to the stoppage, in the second and sixth rounds.

OPBF light-flyweight champion

Simsri vs. Fajardo

On 13 April 2024, Simsri challenged the knockout-artist and reigning OPBF light-flyweight champion Miel Fajardo for Fajardo's first title defense, the bout was held in Edion Arena, Osaka, Japan, Simsri prevailed via unanimous decision, thereby becoming the new OPBF champion, Simsri was down once in the tenth round prior to the decision-announcing.

Simsri vs. Taniguchi

On 15 December 2024, Simsri made his third title defense against former WBO mini-flyweight world champion Masataka Taniguchi in Sumiyoshi Sports Center, Osaka, Simsri successfully defended the title via split decision.

IBF light-flyweight championship

Simsri vs. Araneta

As Masamichi Yabuki vacated the IBF light-flyweight world championship to campaign at the flyweight division, No. 1 IBF-ranked knockout artist Christian Araneta is set to face No. 2 ranked Simsri for the vacant IBF light-flyweight world championship. On 26 April 2025, it was confirmed that their bout was finalized and will take place on 19 June 2025 at the Ota City General Gymnasium in Tokyo, Japan. Simsri defeated Araneta via split decision to become new IBF light-flyweight world champion, Simsri was in control of the early stages but was dropped in the third-round by a counter left hand, Simsri stood up and quickly adjusted, and later controlled most of the bout to win decisively.
After winning the world championship, Simsri dedicated the title to his grandmother, who had died just two days earlier, shortly after he had celebrated his 25th birthday.

Professional boxing record

No.ResultRecordOpponentTypeRound, timeDateLocationNotes
40Win39–1Christian AranetaSD1219 Jun 2025Ota City General Gymnasium, Tokyo, JapanWon vacant IBF light-flyweight title
39Win38–1Songchai SongklodKO3, 0:3522 Feb 2025Singmanassak Muaythai School, Pathum Thani, Thailand
38Win37–1Masataka Taniguchi1215 Dec 2024Sumiyoshi SportsCenter, Osaka, JapanRetained OPBF light-flyweight title
37Win36–1Saravut RongpigTKO2, 0:405 Oct 2024Singmanassak Muaythai School, Pathum Thani, Thailand
36Win35–1John Paul GabunilasTKO5, 2:524 Aug 2024EDION Arena, Osaka, JapanRetained OPBF light-flyweight title
35Win34–1Assada RakmitKO2, 0:591 Jun 2024Spaceplus Bangkok RCA, Bangkok, Thailand
34Win33–1Miel FajardoUD1213 Apr 2024EDION Arena, Osaka, JapanWon OPBF light-flyweight title
33Win32–1Bordin ChomphooTKO1, 0:3416 Dec 2023Singmanassak Muaythai School, Pathum Thani, Thailand
32Win31–1Chiraphan TaosuwanTKO2, 0:2020 Oct 2023Singmanassak Muaythai School, Pathum Thani, Thailand
31Win30–1Shota AsamiKO2, 2:206 Aug 2023City Sogo Gym, Hirakata, Japan
30Win29–1Nawamin KlaypeayoonTKO1, 0:5218 Jun 2023Singmanassak Muaythai School, Pathum Thani, Thailand
29Win28–1Oatsadin ThimthepTKO3, 1:509 Apr 2023Singmanassak Muaythai School, Pathum Thani, Thailand
28Win27–1Weerawat ThongchaichanTKO2, 0:3319 Feb 2023Singmanassak Muaythai School, Pathum Thani, Thailand
27Win26–1Chiraphan TaosuwanTKO5, 0:3618 Dec 2022Singmanassak Muaythai School, Pathum Thanu, Thailand
26Win25–1Sittipon SangteanTKO3, 1:0820 Nov 2022Singmanassak Muaythai School, Pathum Thani, Thailand
25Loss24–1Masamichi YabukiTKO7, 1:1910 Sep 2022City Gymnasium, Yokkaichi, Japan
24Win24–0Kris SriphumTKO3 24 Jul 2022Singmanassak Muaythai School, Pathum Thani, Thailand
23Win23–0Jaturong YuenyongTKO2, 1:181 May 2022Singmanassak Muaythai School, Pathum Thani, Thailand
22Win22–0Benjaphon PhokamTKO2, 1:2027 Mar 2022Singmanassak Muaythai School, Pathum Thani, ThailandWon vacant
21Win21–0Kampanart ValsiripattanachaiTKO4, 2:205 Feb 2022Sasakul Gym, Pathum Thani, Thailand
20Win20–0Natthapon BuasaTKO2, 2:3019 Dec 2021Singmanassak Muaythai School, Pathuk Thani, Thailand
19Win19–0Songkran SosahwatTKO1, 2:5731 Oct 2021Singmanassak Muaythai School, Pathum Thani, Thailand
18Win18–0Chanon SonkhamKO3, 1:4026 Sep 2021Singmanassak Muaythai School, Pathum Thani, Thailand
17Win17–0Thaweesak NakhamTKO3, 1:3018 Jul 2021Hamarith Muaythai, Sa Kaeo, ThailandRetained Thai light-flyweight title
16Win16–0Tongthep Taeyawong4, 3:006 Jun 2021Singmanassak Muaythai School, Pathum Thani, Thailand
15Win15–0Nutthakorn SungseveeTKO3, 0:1919 Mar 2021Kiatkririn Fitness & Martial Art, Samut Prakan, Thailand
14Win14–0Suriya PuttaluksaTKO4, 1:006 Feb 2020Kiatkririn Fitness & Martial Art, Samut Prakan, Thailand
13Win13–0Christian BacolodUD88 Dec 2019EDION Arena, Osaka, Japan
12Win12–0Lerdchai Chaiyawed612 Oct 2019Kiatkririn Fitness & Martial Art, Samut Prakan, Thailand
11Win11–0Nattee ThongsingcleKO3, 1:1731 Aug 2019Kiatkririn Fitness & Martial Art, Samut Prakan, ThailandWon vacant Thai light-flyweight title
10Win10–0Mektison MargantiKO3, 1:464 Aug 2019EDION Arena, Osaka, Japan
9Win9–0Watcharaphon ChaisaiTKO2, 2:2815 Jun 2019Kiatkririn Fitness & Martial Art, Samut Prakan, Thailand
8Win8–0Panuwat YakaretTKO1, 1:3219 May 2019Kiatkririn Fitness & Martial Art, Samut Prakan, Thailand
7Win7–0Ricardo SuenoTKO1, 1:0621 Apr 2019EDION Arena, Osaka, Japan
6Win6–0KermooKO1 5 Feb 2019Prison & Correctional Facility, Bangkok, Thailand
5Win5–0Phirom Padanprasert5 14 Dec 2018Maejo University, Chiang Mai, Thailand
4Win4–0Manop AudomphanawariTKO5, 1:5621 Nov 2018Maetuenwittaya School, Lamphun, Thailand
3Win3–0Suriya PuttaluksaTKO2, 0:5912 Sep 2018Municipality of Bangbuathong, Nonthaburi, Thailand
2Win2–0Prajak ButsreeTKO2, 2:022 Aug 2018Ratirat Villege, Nonthaburi, Thailand
1Win1–0Thanapong Saekoo1, 1:5020 Jun 2018Chinese Taipei Association, Samut Prakan, Thailand