King Abdullah decreed in February that citizens involved in fighting overseas faced up to 20 years in prison in a bid to prevent the radicalization of young people who might then turn against their own government.
While the conservative Sunni Muslim kingdom has backed opposition groups battling President Bashar al-Assad, an ally of Riyadh's main regional rival Shi'ite Iran, it also regards militant groups there as a threat to its own security.
"The accused were proven to have ... quit their obedience to the ruler by traveling abroad to fight," the official Saudi Press Agency reported.
The men were sentenced to terms ranging between four months and two years and 10 months, it said, adding that their crimes included forgery of travel documents and money laundering.
The kingdom has called on citizens fighting in Syria, Iraq and Yemen to return home, often describing them as "misled" in official statements. Saudi state media usually reserves its harshest criticism for militant groups or clerics who recruit young Saudis as fighters.