Welcome to Faliro, Glyfada and Athens south coastline!
Athens also means sea, not olive oil and ceramics. Athens superpower was made because of Acropolis natural position in the center of Attica and its close distance to Piraeus and Faliro.
In Faliro you can visit Marina of Floisvos, the place where private yachts set all year long. There are many cosy restaurants, café and bars, and people enjoy sunny walk at day or night walk at night. Near there is also a ship-war Museum, the famous Averof.
Next destination in Athens coastline is Glyfada. You can get their with a bus or tram (takes longer time with tram).
Glyfada has a big market, similar to that of Kolonaki. Many Athenians go there for shopping, but also for coffee, Glyfada is more expensive- you should know that. Across the coastline Athenians spend their night time mostly, for bouzoukia and nightclubs, especially during summer.
Southern from Glyfada is Voula, Varkiza, Vari and Vouliagmeni. Athenians visit these shores for swimming during weekend and food on Sunday noons. You should be prepared for 1) sun 2) sea 3) coffee 4) fish taverns 5) loud music!!!!
If you move more south, you have the opportunity to reach Sounio, and Posidon temple there, when you can enjoy a coffee or have lunch. Across this route there are many options for beaches!!!!