Iran Air's flights are carried out with jumbo Airbus 300-600 and modern Airbus 320, according to Mehr news agency.
Arbaeen, one of the largest religious gatherings in the world, comes 40 days after Ashura, the martyrdom anniversary of the third Shiite Imam.
Each year, a huge crowd of Shiites flock to the Iraqi city of Karbala, where the holy shrine of Imam Hussein (AS) is located, to perform mourning rites.
Iran and Iraq have signed agreements to remove visa restrictions for the Arbaeen pilgrims, raise the level of services and facilities for the pilgrims, and enhance border security during the pilgrimage season, which will culminate in a large gathering in Karbala on August 25.