Raisi, 63, died on Sunday alongside his foreign minister and six others when their helicopter crashed in the country's mountainous northwest while returning from a dam inauguration.
Thousands of people, holding placards of Raisi and waving flags, marched in the eastern city of Birjand on Thursday morning to bid the president farewell.
His final resting place will be at the holy shrine of Imam Reza, a key Shiite mausoleum in the northeastern city of Mashhad, where the ultra-conservative president was born.
Images published by Iranian media on Wednesday showed officials in Mashhad preparing for the final day of funerary rites.
Large photos of Raisi, black flags and Shiite symbols were erected throughout the streets of Iran's second city, particularly around the Imam Reza shrine.
Massive crowds had gathered for a funeral procession on Wednesday in the capital Tehran to pay their final respects to the president, whom officials and media dubbed a "martyr".
Supreme leader Ayatollah Ali Khamenei -- whom Raisi had been widely expected to succeed -- led prayers for the late president, kneeling before the coffins of the eight people killed in the crash.
Among them was foreign minister Hossein Amir-Abdollahian, who will also be buried Thursday in the shrine of Shah Abdol-Azim in the town of Shahr-Rey south of the capital.
Iranian officials and foreign dignitaries paid their respects to the late top diplomat at a ceremony in Tehran ahead of the burial.
June 28 election
Tunisian President Kais Saied and Qatari Emir Tamim bin Hamad al-Thani attended an afternoon ceremony for Raisi on Wednesday in which around 60 countries took part, said state news agency IRNA.
Member countries of the European Union were among the absentees of the ceremony, while some non-member countries, including Belarus and Serbia had their representatives.
Khamenei, who wields ultimate authority in Iran, has declared five days of national mourning and assigned vice president Mohammad Mokhber, 68, as caretaker president until a June 28 election for Raisi's successor.
A presidential election in Iran had not been expected until next year, and Sunday's crash has caused some uncertainty as to who will succeed Raisi, with some expressing concern about the upcoming president.
"How do I find someone like him? I'm really worried about that," said 31-year-old cleric Mohsen at Wednesday's funeral in Tehran. "As far as I know, we don't have anyone of his stature."
Raisi was elected president in 2021, succeeding the moderate Hassan Rouhani at a time when the economy was battered by US sanctions imposed over Iran's nuclear activities.
The ultra-conservative's time in office saw mass protests, a deepening economic crisis and unprecedented armed exchanges with arch-enemy Israel.
After his death, Russia and China sent their condolences, as did NATO, while the UN Security Council observed a minute's silence.
Messages of condolence also flooded in from Iran's allies around the region, including the Syrian government as well as Hamas and Hezbollah.
