According to the state Antara news agency on Tuesday, all five are suspected members of Jemaah Islamiya (JI) and were convicted under an anti-terrorism law.
The court in the Central Sulawesi provincial capital Palu sentenced three of the men - Nidham Khalid, Fawzan Arif and Fajri - to six years.
Khalid and Arif were found guilty of possessing firearms, ammunition and explosives while Fajri was proven to have financed JI's operations in the province.
It was not clear what the firearms and explosives would be used for.
The Poso district of Central Sulawesi in recent years was the scene of bloody Muslim-Christian clashes which left about 1000 people dead.
The other two suspects, Firmansyah and Aan Hasan al-Din, were jailed for five and three years respectively for sheltering Ahmad Rushan from the authorities.
Rushan was jailed for nine years this month for hiding a key Bali bomber called Mukhlas.
JI has staged a series of bloody attacks in Indonesia in recent years. Indonesian authorities blame it for the October 2002 Bali blasts which killed 202 people.
They are also believed to be responsible for the Marriott hotel bombing in Jakarta last August which left 12 dead, and a series of other deadly attacks.
A lawyer for the five, Tajwin Ibrahim, said they would appeal against what he called politically motivated verdicts.
Prosecutors, who had sought nine years for each of the five, said they too would appeal for tougher sentences.
Indonesian authorities have arrested scores of alleged JI members. Some of them were jailed for their roles in the Bali bombings while others are on trial for the Marriott blast.