The 29-year-old attacking midfielder has most recently played at Adanaspor of Turkey.
Koman made 36 appearances for Hungary national football team from 2010 to 2015 and scored seven goals.
He will join Sepahan after undergoing a medical exam, the Isfahan-based club said.
Sepahan is going to end its title drought in Iran Professional League (IPL) after four years under guidance of Amir Ghalenoei.
Sepahan was held to a 0-0 draw by Sanat Naft in IPL Week 1.