Santorini is not famous for its sea and surely sandy beaches aren't one of Santorini's assets. Still, as in most of Cyclades, you will find enough places to enjoy the wonderful Greek sea.
It is located just below Oia and can be reached either on foot by descending about 200 steps, or by car behind Oia. Essentially it's a picturesque harbor with a background of steep volcanic rocks. Following the path after the taverns you will find yourself on the rocks from where you can dive in the deep blue waters at the edge of the Caldera. You can also swim to Ai-Nikola island and experience some great dives.
White beach is a very beautiful natural landscape surrounded by white vertical rocks, to which it's named after. It consists of white and black pebbles, while the water is quite clear. Access is by boat from Akrotiri and Kokkini beach, while there are some sunbeds to stay protected from the hot summer sun.
At a distance of 11 km from Fira, at the southern tip of the island you will find one of the most impressive beaches on the island, due to the white volcanic rocks, consisting of black sand and crystal clear waters. At the beginning of the beach there is a beach bar and some sunbeds. This is a relatively quiet beach on this island.
One of the most cosmopolitan beaches of the island is Kamari, located on the east side of the island and at a distance of about 9 km from Fira. It consists of black fine pebbles, with deep and crystal clear waters. It is fully organized with several restaurants, cafes, bars and rooms to let.
Red beach is the most famous of Santorini and definitely one of the busiest. The landscape is unique and particularly impressive full of red rocks surrounding the beach. It is located in the southern part of the island and consists of black pebbles, while there are a few sunbeds on the west edge of the beach.
The beach, named after the active underwater volcano of Columbo and is probably the most isolated part of the island for swimming, is located about 10 kilometers from the island's capital. Columbo Beach is a beautiful beach with black pebbles, surrounded by huge volcanic rocks. Park your car on the road and follow a small path to reach the beach. It's pristine and as it's very quiet, it attracts several nudists.
It is an ideal family beach, with black sand and shallow waters while is quite organized. There are several restaurants and rooms to let in the area as the island's airport is quite close.
Baxedes are located in the northern part of the island and consist of the classic black sand of the island. The waters are shallow and for this reason it is preferred by families with children. Access is easy via the coastal road Fira-Oia.
Perissa & Perivolos
Perissa together with Perivolos (one beach is continued by the other) are about three kilometers long and consist of small black pebbles. They are quite touristic and attract a lot of people. The beaches are fully organized and along the promenade lie plenty of restaurants, cafes, bars and rooms for rent.
Of course there are many more beaches, which if you have time are definitely worth visiting, such as Mesa Pigadia, Kambia, Exo Gialos Karteradou beach, Vourvoulos, Pori etc.