Mahmoudi faced
Ryan Sheehan at Best of Siam VII on December 11, 2015. He won the fight by unanimous decision. Mahmoudi won his first major title in January 2018, when he defeated Luca Roma by a first-round knockout to win the WPMF World 61 kg title. In February 2019, Mahmoudi fought Rustam Vyntu at Ring War for the WBC Muay Thai International Super Featherweight title. He beat Vyntu by a third-round TKO.
ONE Championship Elias Mahmoudi made his ONE debut on January 25, 2019 at
ONE Championship: Hero's Ascent, facing Yukinori Ogasawara. He won his promotional debut by unanimous decision. On May 10, 2019, he fought
Petchdam Petchyindee Academy at
ONE Championship: Warriors Of Light for the
ONE Flyweight Kickboxing World Championship. The fight went to a technical decision in the fourth round, as Elias was unable to continue the fight due to an illegal blow. Petchdam won the fight by unanimous decision. He had one more fight with
ONE Championship in 2019, against
Lerdsila Chumpairtour at
ONE Championship: Mark Of Greatness. Mahmoudi won the fight by unanimous decision. He was scheduled to challenge for the Arena Fight title against
Djany Fiorenti during AFC 2, but the fight was later postponed due to the
COVID-19 pandemic. After a year of inactivity, Mahmoudi is scheduled to face former
ONE Flyweight Muay Thai World Champion Jonathan Haggerty at
ONE on TNT 4 on April 28, 2021. However, the fight was canceled for unknown reasons. Mahmoudi faced
Mongkolpetch Petchyindee Academy in the main event of
ONE Championship: Full Blast 2 on June 11, 2021. Mahmoudi lost the fight by majority decision. Mahmoudi was scheduled to face
Walter Goncalves at
ONE Championship: Heavy Hitters on January 14, 2022. However, the bout was scrapped due to
COVID-19 related reasons. However, Mahmoudi withdrew from the bout due to rib injury. Mahmoudi faced
Taiki Naito on August 3, 2024, at
ONE Fight Night 24. He won the fight via knockout in round three and earned the
$50,000 Performance of the Night bonus.{{Cite web |date=2024-08-03 |title=Anane, Mahmoudi, Pirnie Highlight ONE Fight Night 24 Supporting Card With Impressive Wins
Doping suspension Mahmoudi faced Denis Purić on December 7, 2024, at
ONE Fight Night 26.{{Cite web |date=2024-10-30 |title=Denis Purić and Elias Mahmoudi to Face Off in a Top-Five Muay Thai Bout on Dec. 6 ==Titles and accomplishments==