The group - including seven Yemenis and one Syrian national - were convicted of "multiple heinous crimes", including terrorism, state news agency SPA said.
Some were charged with belonging to the Islamic State group (IS), al-Qaeda or the Houthi rebels in Yemen.
Rights organisations say many do not receive fair trials in Saudi Arabia, an allegation the government rejects.
According to SPA, the latest group had been tried by 13 judges and gone through a three-stage judicial process.