The elite Revolutionary Guards said last November it had arrested "several members of an infiltration network linked to hostile Western governments."
Those taken into custody "were working in the country's media and social networks," officials said at the time.
Four men -- two said to be allied with reformist outlets -- and one woman were named and four jail sentences were handed down, state broadcaster IRIB quoted the lawyers as saying.
Davoud Assadi was given a 10-year sentence while Afarine Chitsaz, the woman journalist, received a five-year term.
Ehsan Mazandarani was ordered to seven years imprisonment and Ehsan Safarzayi, five.
Judiciary spokesman and deputy chief, Gholam Hossein Mohseni-Ejeie, said on Sunday that four judgements had been reached, leaving the fate of the fifth suspect, Issa Saharkhiz, unclear.
Saharkhiz was released in 2013 after serving three years in prison on charges of insulting supreme leader Ayatollah Ali Khamenei and publishing anti-regime propaganda.
He was head of media at the culture ministry under reformist president Mohammad Khatami, who was in office from 1997 to 2005.
Signup to our newsletter and follow us on Facebook and Twitter!
In the months before his arrest, Saharkhiz had criticised Khamenei and other senior figures in interviews with foreign media, it was alleged.
The convicted journalists appeared in court on Tuesday and were handed their sentences, the lawyer for three of them, Mahmoud Alizadeh Tabatabaie, told IRIB.
The charges included "colluding to disrupt security and contacting foreign governments," Tabatabaie told Tasnim news agency, which is close to the Guards.
Iman Mirzazadeh, the lawyer for Safarzayi, confirmed his client's conviction to the ISNA news agency.
Both lawyers said their clients would appeal.
Mazandarani ran the reformist daily Farhikhtegan. He was previously arrested in 2009 for acting against national security and for having contact with foreigners, at a time of protests against the disputed re-election of hardline president Mahmoud Ahmadinejad.
Chitsaz was a journalist with government newspaper Iran, according to Mehr, a news agency close to moderate conservatives.
The role of journalists in Iran is frequently the subject of judicial action. Jason Rezaian, the Washington Post's Tehran correspondent and a dual Iranian-American citizen, was arrested in July 2014 and convicted last year of espionage and other charges.
He was freed in January this year as part of a prisoner swap between Iran and the United States that saw several Iranians released.