It is the first time an Indonesian court has passed jail sentences for recruiting and helping people travel to Syria to fight alongside IS.
Last month, IS carried out a series of explosions and gun attacks in Jakarta.
The sentencing judge on Tuesday said that supporting IS should be considered an act of terrorism.
Jakarta-based security expert Sidney Jones told the BBC the verdicts were a step forward but the sentences were too lenient. She said Indonesian anti-terrorism laws are not strong enough.
There were calls in the wake of last month's attack for the country's anti-terrorism laws to be strengthened.
However, members of parliament are concerned about giving too much power to security forces that have a poor human rights record, the BBC's Rebecca Henschke reports from Jakarta.
Four of the group sentenced on Tuesday had travelled to Syria to undertake military training with IS.
The other three had helped purchase tickets and recruited people to join the jihadists.
Indonesia's new breed of militants
A court in Indonesia has sentenced seven men to between three and five years in jail for supporting the so-called Islamic State (IS) group.