Santorini's position in the southern Cyclades makes it a natural base for exploring the caldera islands and nearby archaeological sites. The most rewarding excursions can be done independently with a ferry or local tour, and most take a full day.
Caldera Islands: Nea Kameni and Palea Kameni
The two volcanic islets in the centre of the caldera are the island's most popular day trip. Nea Kameni is an active lava islet — you can walk to the steaming summit crater in about 20 minutes. Palea Kameni nearby has a hot spring where you can swim in warm, sulphurous orange water. Boats leave from Athinios port and the old port below Fira; half-day group tours are easy to join.
Ancient Thira
On the ridge of Mesa Vouno between Kamari and Perissa, Ancient Thira is a Hellenistic and Roman town with remains of temples, a theatre, markets, and baths. The site is accessed by a steep road — you can drive, take a taxi, or hike up from Perissa (about 45 minutes). The views from the ridge across to both coastlines are excellent.
Thirassia
The small inhabited island on the western arc of the caldera is the quietest part of the Santorini group. Ferries and tour boats stop at the fishing village of Korfos. It gives a sense of what Santorini looked like before mass tourism, with fewer than 300 permanent residents and almost no development above the port.