Sunni Saudi Arabia and Shia Iran were on opposing sides of the proxy war in Syria, with the Saudis joining the US and NATO countries in fueling the decade-long conflict there. 

Saudi-owned Al Arabiya news network confirmed the reopening, reporting that "Footage aired by al-Hadath TV, a sister channel of Al Arabiya, showed the Iranian flag being raised outside the embassy building in Riyadh, accompanied by the playing of the Iranian national anthem."

While the Saudis have yet to reopen their embassy in Iran, it's expected that ease of travel, visa access, Islamic pilgrimage for Iranians connected to the Haj, and the resumption of direct flights will be the first result. 

In March The Wall Street Journal cited that CIA Director William Burns told Crown Prince Mohammed bin Salman in a meeting that the US "has felt blindsided" by Riyadh's rapprochement with Iran as well as Syria, two nations under crippling US economic sanctions.