As the islands of the Saronic Gulf in Greece are located so close to Athens and they are usual summer weekend breaks, the options for nightlife in Saronic are many. The most cosmopolitan islands of Saronic are Hydra island and Spetses island. The port of Hydra and the old port of Spetses are lined up with many bars and clubs that stay open all night long and organize dance parties.
Aegina island and Poros island are also nice Greek islands to spend a night out, although things are more lounge there. Agistri, the smaller island of Saronic, has lounge cafeterias that turn into bars at night. For a more peaceful evening, try a long dinner in the many seaside taverns of the islands. These taverns usually stay open till around midnight.