- The most important attraction is the Venetian Castle in Chora, the island’s capital. It was built by the family of the Querini in the 13th century AD and occupies an area of around 4,000 square meters. Architecturally, it constitutes a fortified settlement, in which the outer walls of the houses create a wall with small windows for loopholes. It is built with traditional local dark stone and offers magnificent views of the two natural harbours on the island. The houses of Querini are built around the entrance on the east side. It was inhabited until 1956. Inside the castle, there are two churches, the Church of St. George, the oldest church on the island, and the church of Panagia (Virgin Mary) of the Castle, which is built by the tower above the gate.
- The Archaeological Museum of Astypalaia is housed in a small ground-floor room that was given by the Ecclesiastical Charity Fund of Astypalaia in 1994. The Museum was inaugurated in September 1998 and its collections include findings from the Prehistoric and Medieval eras.
- In the southern part of Chora, in the Kylintra region, there is a unique, ancient baby cemetery, a large area, where about 3000 jar-burials were discovered. Dating from the Geometric period and used until the Hellenistic era and, newborns from different regions of the Mediterranean were buried there. At the site were found hundreds of babies buried in earthen vessels, of great archaeological and anthropological interest. There are several theories about how this burial place was. The two dominating are that either this was a possible offer to the gods, parents offered their dead babies in deities of childbirth Artemida Sergeant and Eileithyia so as to have a live baby in the next birth or that deaths resulted from natural causes during childbirth.
- In the village Maltezana, are the Baths of Tallara found in the Late Roman period. They constitute a complex of Hellenistic mosaics with excellent colors and technique, where the Zodiac and the personification of Time represented the seasons and months in the main hall respectively.
- In Vathi, the Minoan relics can be found. This is a particularly extensive prehistoric settlement in the lagoon formed at the entrance of the bay.
- In the southwest side of the island, just 12 km from Chora, stands the Castle of St. John. It was built opposite the monastery and is a natural fortress with a secret entrance and passage to the next hill. According to the traditional tail, the castle was impregnable, and was a refuge for the inhabitants from pirate raids. Nowadays, ruins of the castle and a cistern have survived. The access so as to reach the castle is difficult. From the beautiful church of St. John to the left, starts the steep path to the beach. The landscape with running waters, oleanders and small waterfalls is magical.
- The island has three caves which are inextricably tied to the tradition of the place, and their exploration is a great experience. In Vatses is the Cave of the Negro (Black), which features unique clusters of stalagmites and stalactites. There are several myths about pirates and their treasures hid in it. In Vathi, in the north of the island is the Cave of the Dragon, or otherwise Drakospilia. Inside there are impressive stalactites and stalagmites. It is accessed either by boat or by car, up to a point, and then a short walk. Finally, in the highest mountain of the island, Kastelanno, is the cave of Panagia (Virgin Mary) Poulariani.
- Other attractions of the island include the Tomb of the French admiral Biggon in Schoinontas, reminiscent of the French sailors preferring to blow themselves than fall into pirate hands, the square of the Chora, the Narcisse’s Municipal Library, the Seraglio, a four-storey square tower, 18 meters in circumference, Castellano that is located on the highest peak of Mesa (366 meters altitude), which during the Italian occupation (1912-1943) hosted Italian fort and camp, Panagia (Virgin Mary) Poulariani with low vegetation, beehives (which incidentally produce amazing honey), the mosaic floor of the Basilica chair in Schoinontas and remains of a Christian basilica of the 5th century, with remarkable mosaics in Maltezana.