Zante to Athens via south Peloponnese in 10 days realistic?

I would be very surprised if you could find a car rental company that would allow you to pick up the car in Kyllini and return it to Athens.

Even if it were possible it would cost you more than a flight from Zante to Athens.

@JoLui We have no issues finding a car rental in Zante to return in Athens and we can take the car on the ferry. There is no point flying from Zante to Athens as we want to visit all the places in between so that's not a very helpful comment! Cost is not a major concern.

We have no issues finding a car rental in Zante to return to Athens
and we can take the car on the ferry.

Have you figured out how much it will cost you?

Probably as much or more than a week's rental, and you will have to pay the ferry ticket for the car.

As I've said already @JoLui, cost is not a concern for us. We'll be staying in 5* hotels. The travel part costs are really inconsequential to me. I have already priced this up. It's only another £300 to the whole trip. I'm not sure why you care so much about the costs when I've already said it doesn't matter to me. Could we get on with answering the question I actually asked please?

Sorry for being redundant but you didn't specify that the extra cost didn't matter to you, whatever it was.

For the vast majority of posters who ask questions here the travel part costs are not inconsequential, and in your case they would have changed their plan, especially for a short stay of 10 days.

Back to your itinerary, I may be rude and trigger another annoyed reaction from you, but since it's a question of being "realistic" I don't see the point of going to Zante to stay only one day, even two. You will only stay one night at best, and as soon as you arrive you will have to leave.

Then, going through Kalamata on the way from Zakynthos to Gythio, although longer by at least 1h30 is worth it, but you will not have time to enjoy much even if you leave by the first ferry in the morning. It will be a day mainly dedicated to driving on winding mountain roads.

If you plan to stay 2 days in Gythio, you are on day 5.

Adding a night in Elafonisos (also useless), a night in Monemvasia, "some time in Nafplio" which deserves at least 3 nights, and finally your last day in Athens, you have spent more than 10 days.

In my opinion if you are going to be bored it is mainly because of the long hours you will spend in the car instead of visiting the Peloponnese.

Seems like you would be better off just flying round trip to ATH and doing a loop--to Gytheio is just three hours, to Nafplio is a snap (we drove there on arrival).

I would agree that flying in and out of Athens would be more efficient.

That isn’t one of the options as there would be too much backtracking. We don’t like going backwards. And we’d like to spend some time in a high end hotel which probably means going over to the west coast anyway.

If you did a loop, the only backtracking would be a short stretch of highway from Corinth to Athens, so I don't understand that, but good luck!