@zoe How about…
Hydra, a charming, car-free island with beautiful stone mansions, cobblestone streets, and a peaceful atmosphere. It’s close to Athens (under two hours by ferry from Piraeus), making it a perfect first stop.
Highlights include a quaint harbour, traditional tavernas, seaside walks, and some small beaches. No cars means it’s very tranquil.
Naxos, the largest island in the Cyclades, offers beautiful beaches, traditional villages, and ancient ruins like the Portara (Temple of Apollo).
It’s larger and less touristy than Mykonos or Santorini, but still accessible by ferry from Hydra.
Amorgos, known for its dramatic landscapes and peaceful atmosphere, is ideal for hiking and quiet beaches; reachable by ferry from Naxos.
Visit the stunning Monastery of Panagia Hozoviotissa clinging to cliffs, and traditional villages like Chora with narrow alleys.
You could then include Paros or Milos.
Paros - Slightly livelier but still charming with traditional villages like Lefkes.
Good for beaches and tavernas, and easy ferry connections to Naxos and Amorgos.
Milos - Known for unique volcanic beaches and dramatic coastline, more rugged and less touristy than Santorini.
Return to Athens from Paros, Milos, or Naxos for your flight home.