Friday 18 September has been set aside for possible one-day trips and excursions for participants with departure flights on the next day. Cost varies with destination and type of trip and direct on-line booking is possible through a variety of web sites, see e.g. lonelyplanet, travelporter, viator etc.
Recommended alternatives are:
• A trip to one of the following islands: Kea, Aegina, Hydra, Poros, Spetses,
• An excursion to Argolis (Mycenae, Nafplion and Epidauros) or Delphi
• A cruise to the Saronic Gulf islands (Aegina, Poros, Hydra)
A relaxing day at some beach of the Athens Riviera beach is certainly another attractive option. There are several organised beaches with entrance and/or facilities usage fees, as well as several free beaches. Shade seeking under trees or umbrellas is a must.