Elafonisos is a small island very close to the coast of the Peloponnese. It is connected from the port of Vinglafia (Punta) (10 minutes, many daily crossings) and from Neapolis (30 minutes). In high season, it can also be reached from Piraeus via the Southern Peloponnese ferry, and from Kythira.
The main operator is N.E. Elafonisos; tickets are purchased directly at the port without reservation. KTEL buses from Athens or Sparta reach Neapolis, where you can board the ferry.
The island does not have an airport. The closest is Athens International Airport; from there, a bus or rental car takes you to Neapolis (about 5 hours).
Connections are more frequent during the summer season; always check availability if travelling in other periods.