If you can expand on any of these and clarify the locations and photos, do let the Cap'n know. He'll spin them off into their own entry.

The first location is below cliffs north of Aegina town. Go out past 'Colona' archaeological site and you will immediately pass a narrow (textile) beach - much quieter than the 'town' beach seen before Colona. Keep going with Danae Hotel on right. After about half a km there are a couple of access paths down the cliff and nude swimmers are often seen swimming from rocks.
See probable location on Google Maps

From my recent [2018] trip to Aegina the first location was pretty much the only place where you could swim or sunbathe naked. The beach itself isn't pretty but the view back towards the Colona site was nice. The instructions to get there are very accurate, just past the Danae Hotel you will find a nice shaded area of pine trees to park your car or bike off of the road. From there you can follow the small track down to the beach, it's a little steep but not hard and best avoided in flip flops, the most comfortable place to lay was on the dry sea grass. We went 5 times over two weeks and were the only people sunbathing there. Occasionally some locals would come down for a swim, we saw maybe 5 people in all the time we spent there and only one other person skinny dipping but nobody bothered us at all or batted an eyelid. The snorkelling is amazing around the rocky headland but rock shoes are a must for entering the water.

We tried the second and third locations listed here but found that it was impossible to go in the water and swim naked from the rocks.

The second location is about 1km after this. Pass the church/lighthouse. Pass the Lady statue and the Delphini Taverna. Go until the road turns a sharp right. Immediately before the turn there is wooded land on left going down to the sea. This area is not much used and there is a small pebbly beach which is screened by the trees from the houses up at the road.

See second & third places on Google Maps

A third possibility is right on the corner where the road turns right. You will see there are two paths down to the left and several rocky places to swim from.
None of these are the wonderful idyllic beaches found in other areas but at least on Aegina, now we can have a proper swim…and the water is wonderful and clear.

A new opportunity has arisen with frequent if isolated nudity on the beach just after Colona on the way out of town. This is promising as it is a short walk from the town and ferry terminal. The beach with Colona to the left is narrow and long. Go [North] to the far end (away from Colona). There is a great deal of seaweed which means this is the less popular end and isolated nudist swimming is becoming more common.

See Kolona Beach on Google Maps