The panel of judges on Thursday said Wirahadi, 21, had transported and hidden the bomb before its use in the eastern city of Makassar, about 1400km east of Jakarta, the national news agency Antara reported.
"The defendant was convincingly and legally found guilty of carrying out crimes in an act of terror," said presiding judge Said Mado.
More than 15 people have been convicted of involvement in the December 2002 blast, with sentences ranging from two to 19 years.
Wirahadi had also planned to set off a bomb at a Kentucky Fried Chicken restaurant in the port city but failed to do so, Antara said.
Bali convict jailed
Separately, another man was jailed for six years after hiding one of the bombers responsible for the October 2002 Bali blasts, which killed 202 people.
Hafidin, also known as Munawar, was found guilty of sheltering the convicted Bali bombing mastermind, Imam Samudra, who was sentenced to death for his role in the attacks. Most of the victims were foreign tourists.
The sentence was less than the nine-year jail term prosecutors had wanted. Hafidin did not respond to the verdict and it was unclear if he would appeal.
More than two dozen men linked to the Bali blasts have been tried and given sentences ranging from three years' jail to death.