The port, located in Iran's southeastern Sistan- Baluchestan Province, is scheduled to be inaugurated by Iranian President Hassan Rouhani in presence of representatives from India, Afghanistan and several other countries of the region.
The first phase of the Chabahar port project is known as the Shahid Beheshti port.
Ahead of the inauguration, External Affairs Minister Sushma Swaraj and her Iranian counterpart Javed Zarif held a meeting on Saturday in Tehran and discussed about the Chabahar port project among other issues.
Iranian Foreign Ministry said Mr Zarif referred to the Shahid Beheshti Port and said it reinforces Iran-India mutual and regional cooperation.
"It also shows the importance of the port in the development of the region and the routes that connect Central Asian states to other countries in the world through the Sea of Oman and the Indian Ocean," he said, according to the Iranian Foreign Ministry.
Ms Swaraj made a stopover at Tehran on her return from Russian city of Sochi where she had attended the annual summit of the Shanghai Cooperation Organisation (SCO).
The port is likely to ramp up trade among India, Afghanistan and Iran in the wake of Pakistan denying transit access to New Delhi for trade with the two countries.
Over a month ago, India had sent its first consignment of wheat to Afghanistan by sea through the Chabahar port, marking opening of the new strategic transit route.
A minister from India is attending today's event. The Iranian president's office said the Shahid Beheshti harbour will be opened today.