The 33 are part of a group of 71 people who have been on trial since yesterday for various charges including accusing the kingdom's rulers of "infidelity", said SPA
They were also convicted of "smuggling a number of prisoners" out of jail as well as "targeting clerics, princes, and members of the security forces," the agency said.
Their prison terms range from six months to 30 years.
The cell members were arrested when security forces raided their hideout in Riyadh in 2007 in an operation that left one member of the security forces and six of the group dead.
It is unclear if the court will continue the trial of the remaining 35 defendants.
The trial is the latest in a series of prosecutions that began in July 2011 for alleged offences committed during the peak of Al-Qaeda violence in the kingdom between 2003 and 2006.