The two nations announced last March 10 an agreement to resume diplomatic relations.
Iran on Tuesday opened its embassy in the Saudi capital, Riyadh, after seven years of diplomatic rupture. The country is also set to reopen its consulate in the Saudi city of Jeddah on Wednesday.
Iranian Deputy Foreign Minister Alireza Begdali and Iran's representative in Jeddah Hassan Zarnagar Abargoui were present at the ceremony for reopening the Iranian embassy.
Iran's deputy foreign minister expressed his satisfaction "to be present in the brotherly and friendly country of Saudi Arabia," noting that the two countries are entering a new era in terms of cooperation.
Late last month, Iran appointed senior diplomat Ali Reza Enayati as its new ambassador to Riyadh.
The agreement signed between Iran and Saudi Arabia includes, in addition to the reopening of the Iranian embassy in Riyadh, the official reopening of the consulate general in the Saudi city of Jeddah and the office to the Organization of Islamic Cooperation (OIC), the Iranian Foreign Ministry has said.
Both nations announced last March 10 an agreement to resume diplomatic relations and reopen embassies and representations within a maximum period of two months. Iraq and Oman brokered the negotiations for two years, while China mediated the final round of talks.
Saudi Arabia closed its embassy in Tehran and consulate in Mashhad in January 2016 following attacks on its diplomatic headquarters after the execution of prominent Saudi Shia cleric Sheikh Nimr Al-Nimr.