The opening ceremony reportedly took place a few hours after the announcement of the Iranian delegation's arrival in Riyadh on Wednesday.
On Tuesday, the Iranian Foreign Ministry sent a technical delegation from Tehran to Riyadh to prepare for the opening of the Iranian embassy in Saudi Arabia's capital and the consulate in Jeddah.
In early March, Iran and Saudi Arabia, with China's mediation, agreed to resume diplomatic ties that were severed in 2016 after Saudi Arabia's diplomatic missions in Iran had been attacked following the execution of Shiite preacher Nimr al-Nimr.
Last week, Iranian Foreign Minister Hossein Amirabdollahian and his Saudi counterpart, Prince Faisal bin Farhan Al Saud, met in China and signed an agreement on the restoration of diplomatic relations and preparation for the opening of diplomatic missions. They also agreed to resume direct flights between the two countries.