In fact, it's the new port of Arhinios, located 5 Km to the south, that receives practically all the maritime traffic of the island.
Here arrive the large ferries and fast catamarans from Athens or Heraklion (Crete), and thanks to a paved road, supply Santorini with all sorts of goods... (and tourists!)
Indeed, the 2 main ways to arrive in Santorini are either by sea, presumably at this new port, or by air, at the very small airport located on the west of the island.