A banner reading 'Free all Saudi prisoners' was flown over St James Park as Newcastle hosted Arsenal in the Premier League on Sunday.
The protest comes amid the Saudi Arabia's Public Investment Fund's backing of Newcastle, after a takeover was completed in 2021.
The Saudi regime has been been heavily criticised by human-rights groups for multiple alleged offences.
This includes the exploitation of migrant workers, criminalising the LGBTQ community and the imprisonment and torture of anti-Saudi dissidents.
The banner also referred to the SANAD Organisation – short for Standing Against Nefarious and Arbitrary Detentions.