[5] Demirtaş internationally debuted at the Freestyle Wrestling – Junior World Championships 2010 held in Budapest, Hungary, where he captured the silver medal.

[9] He lost to Narsingh Pancham Yadav from India in the round of 16 at the 2015 World Championships in Las Vegas, United States.

[2] In March 2021, he competed at the European Qualification Tournament in Budapest, Hungary hoping to qualify for the 2020 Summer Olympics in Tokyo, Japan.

[11] In 2023, Soner Demirtaş, competing in the 2023 European Wrestling Championships freestyle 74 kilograms, defeated Azerbaijan's Dzhabrail Gadzhiev 5–4 in the repechage match.

[12] He won the silver medal in the men's 74 kg event at the 2024 European Wrestling Championships held in Bucharest, Romania.