After arriving in Piraeus from a cruise of the smaller Greek islands we will have 3 days before our flight back to England.
How best can we spend it.
Would you be willing to share a bit more about your interests?
If you’re not planning on staying in Athens, and want a historical location (all of Greece is historical, really, isn’t it?), consider Nafplio. It’s also fairly convenient for daytrips to the archeological sites of Mycenae and Epidaurus, and also Nemea.
Athens alone could fill your three days. Are you thinking of one place for three nights, or potentially moving from place to place, staying just a night or two somewhere? And how would you be getting around - rental car, bus, train, taxi?
Good information by Cyn.
Central Athens for three days gives you sufficient time to explore the ancient sites in Athens.
If Athens is not in your planning then Nafplio is a good destination. Its on the mainland but the old town area feels like you are on a Greek island.
Some images of Naflpio
https://www.flickr.com/photos/stanbr54/albums/72177720319228274/