Saudi Press Agency described it as the largest known mass execution carried out in the kingdom in its modern history.
The kingdom had earlier made a record 67 executions in 2021, a massive rise from the 27 carried out in 2020.
“These individuals … were convicted of various crimes including murdering innocent men, women and children,” SPA said on Saturday, citing a statement from the interior ministry.
“Crimes committed by these individuals also include pledging allegiance to foreign terrorist organisations, such as ISIS [ISIL], al-Qaeda and the Houthis,” it added.
Some travelled to conflict zones to join “terrorist organisations”, according to the SPA.
Of the 81 executions, 37 Saudi nationals were found guilty in a single case for attempting to assassinate security officers and targeting police stations and convoys, according to the report.
Saudi’s execution is usually carried out by beheading with a sword but may occasionally be performed by shooting.