Since 2015 over 150 Christians have been detained by authorities in the country and many kept without reason.
One of them, Mohammad Reza Omidi has now been granted bail in the northern city of Rasht, according to World Watch Monitor.
He was asked to pay $33,000 (around £23,000) for his release, the same amount as detained Christians Yasser Mossayebzadeh and Saheb Fadaie.
The pair were released a week earlier.
Iran:
Leader: Ayatollah Ali Khamenei
Population: 80 million - around 475,000 Christians
Main Religion: Islam
Government: Islamic republic
World Watch List Rank: 9
The three men were arrested in May alongside an Iranian pastor.
Pastor Youcef Nadarkhani has previously been sentenced to death for apostasy, alongside his wife Tina.
The couple were released the same day but the three men remained in custody.
Many Christians still remain in jail but Mossayebzadeh, Fadaie and now Omidi have now been released conditionally, pending sentencing or an appeal.
Iran ranks at number nine on Open Doors World Watch List.
