Saudi Shias have staged small demonstrations in the eastern province, which holds much of the oil wealth of the world’s top crude exporter.
The province is near Bahrain, also the scene of protests in recent weeks by majority Shias against their Sunni rulers.
“Twenty-two were arrested on Thursday plus four on Friday, so the total is 26. This was all in Qatif,” said rights activist Ibrahim al-Mugaiteeb, who heads the independent Saudi-based Human Rights First Society.
A Shia activist in the province’s main town of Qatif also said he knew of 22 arrests.
Saudi Interior Ministry officials could not be reached for comment.