Starting Athens to Aigina the small town around the harbor is a pleasant homely sort of place. The single column on Ak Kolona is all that remains of the temple of Afrodite that formely stood on the cape. Good tavernas around the waterfront and good shopping for provisions.
Perdika the bay is an attractive place !Get here early and take some time off for a wander around the village and a beer on the seafront! Good tavernas on the waterfront, some of which specialize in seafront!
It's a good shelter with several cafe and tavernas ashore. The hamlet is a delightful spot and well off the Sarnic charter milk run. On the black basalt slopes there is an old caldera betraying the peninsula's recent volcanic origins!
Ermioni walk over the saddle of the town where things are peaceful and you can sit in a bar on the waterfront with wonderful views over the water. Hardware shop and good shopping for provisions.
Spetsai the old harbor and environs is a wonderful place to wander around. Around the harbor are many grand old houses built in a prosperous era of the 18th and 19th centuries. Spetsai restaurants often have an excellent dish peculiar to the island which is well worth sampling! After that you can visit Ydra, the island of the ancient Greek poets, where you can find some nice taverns and good shopping for the provisions.
Poros the small volcanic peninsula on which Poros town is built was known in ancient times as Sphaeria. Very popular island and provides everything!