Debating 3 different Greek islands - itinerary help

We had a very similar trip last summer in June, family of 4 with a 15yo and 13yo.

We had 3 nights in Athens, and during our second full day in Athens we did an all day sailing trip out of Piraeus Port. A bus picked us up near our hotel, took us to the port where we got on the boat. We went to 3 islands, Agristi, Aegina, and then one that was uninhabited where we really just anchored and swam. We got in the water at Agristi - it was very rocky and not the clear water you think of. In Aegina we walked to some ruins and then had ice cream (they are a huge pistachio producer, so I had to have pistachio ice cream). We didn't swim there, but there appeared to be a beach somewhat better than that at Agristi.

Picked up our rental car after our 3rd night in Athens, then had 3 nights in Nafplio, 2 nights in Delphi, came back to the Athens airport where we returned the car and flew to the island of Naxos for 4 nights. Navigating the airport again was stressful, but it was an easy 45 minute flight. We loved Naxos, it was gorgeous. Flew back to Athens, and then home the following day.

So anyway, of the 4 islands you list, I wouldn't choose to stay on Aegina. I did like it, and I would like to have had more time there, but it just isn't somewhere I would want to dedicate 2-3 nights to. I haven't been to the others but I have a friend who stayed on Hydra and really loved it. As far as Zakynthos, for most of my early planning, I had been thinking we would stay either there or Kefalonia, doing exactly as your #4 option, until I got it in my mind to fly to an island instead. The pictures of the Ionian Islands really appealed to me, and it seemed like there would be a good variety of activities there. In fact, we drove over that way when we went from Nafplio to Delphi anyway, as I wanted to travel around the Gulf of Corinth rather than backtrack back past Athens. So, Zakynthos is definitely what I would choose from your options. Just make sure your rental car can go on the ferry, as I have heard there are sometimes limitations about that.

I don't recommend option 4, too much travel in too little time. You will spend a good part of your stay in Greece in a car checking the GPS and visiting the country from behind a windshield.

Option 1 seems perfect to me provided you modify a few details...

Arriving at 10:00 a.m. go directly by taxi to the port of Rafina, it is 20 minutes from the airport. (there are no ferries leaving from Porto Rafti)

You don't need to rent a car at the airport.

It will be of no use until you are on the island, you will pay extra insurance and an expensive ferry ticket for the car (not including the rental hours paid for nothing while the car is on the ferry).

Instead of going to Andros I recommend Tinos, it's the next island on the ferry route. Tinos is a very beautiful island full of villages to explore and with some beautiful beaches easily accessible.

You can take the fast catamaran "Tera Jetc" at 2:30 p.m., at 4:40 p.m. you will be in Tinos. While waiting for the ferry you can have lunch in one of the taverns in the port of Rafina.

https://tinosecret.gr/en/

Some pictures of Tinos:

https://photos.app.goo.gl/4sAxvcMJY2KAegrE9

To tinos I recommend the car rental company Vidalis.

Good cars, large choice (including automatics), attractive prices and very friendly staff.

https://www.vidalis-rentacar.gr/.

After Tinos, go back to the airport: Ferry Tinos→Rafina then taxi Rafina→Athens Airport and rent a car at the airport to go to Nafplio.

It's that simple.

Lindsay, you earlier had thread about trip - https://community.ricksteves.com/travel-forum/greece/itinerary-suggestion-1-5-weeks-greece-family-of-4 In it, I gave many details about NAFPLIO sightseeing & swim oppties, also chance to see ANCIENT NEMEA just before its exciting "Ancient Games" event. Thus won't repeat. Will just add dates omitted in this thread -- may affect others'advice.
You arr Sat June 15 10 AM and Dep Wed June 26 - thus 10.5 days. With Athens last, not first ( too exhausted from long journey, stuff won't mean as much, all a blur etc).

I think Jo-Lui's advice about Tinos on Day #1 is excellent -- https://www.greektravel.com/greekislands/tinos/ it meets your criteria of fairly easy to reach & good beaches ... if you're just staying for 3 nights (2 days) you may not need a car.. just get to a good beach & "veg out" - https://www.greektravel.com/greekislands/tinos/beaches.htm Another reason for Tinos; you arrive isl. on a weekend, and the other isles, HYdra & Aegina, are packed on weekends w Athenians doing a getaway, Tinos not at all. Agree also about taxi to Rafina & back to Airport. On Tuesday Jun 18 DO catch the only morning ferry (arrives Rafina Noon); take picnic lunch so you can get airport rental car & be off for Peloponnese before 1 pm... maybe munch at Corinth, or Nemea?

As for Delphi, give it thought. Are you Classics buffs, immersed in history/mythology? If not, you might need pvt guide (€60 per hr, 2-hr min) to make sense of ruins. Or Mainly want mountain scenery? If it's just heights you're after, yr Peloponnese route can offer Acrocorinth, and Nafplio has its own "Gibraltar", Palamidi (Photos taken their seem to be taken from airplanes!). Just be sure u are not going in order to check it off a list... it's a 3.5 mi drive, whether you go straight f rom Athens, or enroute back from Nafplio.