The great ruins are among the most notable in Asia Minor. They cover a large promontory which a wall and a moat separate from the mainland. Archaeologists have been excavating Side since 1947 and intermittently continue to do so

The colossal theatre complex of the 2nd century is less well-preserved that of Aspendos, but it is almost as large, seating 15,000–20,000 people. It was converted into an open-air sanctuary with two chapels during Byzantine times (5th or 6th century). The well-preserved city walls provide an entrance to the site through the Hellenistic main gate (Megale Pyle) from the 2nd century BC. The colonnaded street had marble columns whose remains can be seen near the Roman baths, restored as a museum displaying statues and sarcophagi from the Roman period. The agora includes the remains of the round Tyche and Fortuna temple (2nd century BC), peripteral with twelve columns, in the centre. In later times it was used as a trading centre where pirates sold slaves. The early Roman Temple of Dionysus is near the theatre. The fountain gracing the entrance is restored. At the left side is a Byzantine Basilica. Other buildings include three temples and a nymphaeum, a grotto or fountain building of elaborate design, and a synagogue which was discovered under a modern place of residence.