All had been “found guilty of committing multiple heinous crimes”, the official Saudi Press Agency (SPA) reported, saying they included convicts linked to the Islamic State group, or to Al-Qaeda, Yemen’s Huthi rebel forces or “other terrorist organisations”.
They had been plotting attacks on vital economic sites, or had targeted or had killed members of the security forces, or had smuggled weapons into the country, the SPA added.
Of the 81 people, 73 were Saudi citizens, seven were Yemeni and one was a Syrian national.
SPA said all those executed were tried in Saudi courts, with trials overseen by 13 judges over three separate stages for each individual.
The wealthy Gulf country has one of the world’s highest execution rates.
Saturday’s announcement marks the kingdom’s highest number of recorded executions in one day, and more than the total of 69 executions in all of 2021.