Korkai, Poompuhar, and Muchiri were prominent ancient port cities in South India during the Sangam period (c. 3rd century BCE to 3rd century CE). They played a vital role in maritime trade between India and the Roman Empire, as well as Southeast Asia.

• Korkai: Located at the mouth of the Thamirabarani River in present-day Tamil Nadu, it was an important port of the Pandya dynasty. It was particularly famous for its pearl fishery.
• Poompuhar (also known as Kaveripattinam): Situated at the mouth of the Kaveri River, it was the chief port of the Early Cholas. It is vividly described in Sangam literature (like Silappadikaram) as a bustling hub of international trade.
• Muchiri (Muziris): Located on the Malabar Coast (modern-day Kerala), it was a major port of the Chera dynasty. It was the primary center for the pepper trade with the Roman Empire.

Note: In Sangam literature, the term 'Puhar' specifically refers to a river mouth or a harbor town where goods were discharged.