Athens Airport: Expected Custom's Time and Itinerary Help

What you really need to know is how long does it take to get through Passport control.

This is what you can expect.
1) go to passport control. Once cleared.
2) Pick up your bags
3) Pass through the exit door. The door has a sign that says Nothing to Declare. That is customs. You are now in public area of arrivals level.
4) go up to the next level, stairs elevator or escalator.
5) I presume you will have already printed your boarding pass for your connecting flight. Both Sky Express and Olympic allow you to do that 48 hours before your flight.
So all you have to do is drop off your luggage. You can go to the airline desk or as I recall there is a machine where you can print your own luggage tags.
6) right near that luggage tag machine you will see the bag drop off conveyor, drop your bags.
7) go to security. Athens airport has the most efficient security check process I have ever experienced.
8) head to your gate. You will likely have time for your first Mythos beer on the way.

2 hours is the amount of time you you need to have to make the connecting flight.

Your plan is fine.
Companion islands for Santorini both Naxos and Paros are great choices. I am biased towards Naxos. You will save an hour by taking the ferry to Naxos as Paros is further from Santorini.

I would fly back to Athens as you will save a few precious hours over using the ferries.
Nafplio is a good choice as there are several antiquities in that area.

Good call to save Athens to the end of the trip so you are on the mainland the night before your return flight.

If this was my trip I would ferry to Naxos and spend 5 nights there and return to Athens for three. Nothing against Nafplio we love it but you will find 3 nights in Naxos is simply not enough time as Naxos takes a minimum of a week to begin to experience what Naxos has to offer.
I will temp you.
Naxos town 2022 https://www.flickr.com/photos/stanbr54/albums/72177720299959098
Naxos town 2024 https://www.flickr.com/photos/stanbr54/albums/72177720318203165/

Trip around Naxos https://www.flickr.com/photos/stanbr54/albums/72157634605629689

Since July is a very busy month, to have a margin of safety I'd say a 3 hours connection time is a good compromise.

On Monday, July 14th, I won't be taking the 11 a.m. Aegean flight to Santorini, but one of the following flights. (The next one is a Sky Express flight at 12:50.)

Regarding your hesitation between Paros or Naxos, I'll be frank:

It doesn't matter since you're only planning to stay there for 2 nights.

2 nights is only one full day, so you won't have the opportunity to visit much more than the port and its surroundings. But it will require a ferry ride, check-in and check-out from your hotel, plus possible port-to-hotel transfers. Just for a few hours on the island? It's not worth it.

If I were you, I would head straight to Athens and the Peloponnese, skipping Naxos or Paros.

To get to Nafplio, you can rent a car from the airport or the port of Piraeus, depending on whether you arrive by plane or ferry.
In both options, you won't go through the center. From Athens.

By taking a ferry to the port of Piraeus, you'll likely arrive later than by taking a morning flight to the airport.

I also would skip the second island. It will take you half a day to get there and then you have to get back to mainland. Doing the math, it is a day of traveling for one full day in a second island.

You could add a day easily to Nafplio. There are lots of day trips you can take and you can also spend time at a beach. We hit very hot weather in June (high 90s) and would go touring in the morning and to the beach in the afternoon.

You could add the other day to Athens or if you want more island time, to Santorini.

2 hours is the amount of time you you need to have to make the connecting flight.

ASSUMING your flight arrives on time.

Will you be on a direct flight from "home" to Athens, or will you have to change planes somewhere along the way?

Checked bags? If you plan to do only carry-on, does it conform to the size/weight limits for the Santorini flight?

Thanks, Joe. We have a 3 hour layover in the states before being direct on to Athens. We are planning to do just carry on - duffle bag and backpack, as wanted to pack light for ease of moving around.

Stan - the Naxos pictures are amazing, so it is tempting! If we extended, what would be the highlights you would suggest there?

JoLui and Beth - thanks for the feedback. If we skipped Naxos and took one of the nights to add to Nafplio, what day trips would you suggest? We were planning to Epidavros and Mycenae on our way in and out of the area. Would Hydra be a day trip or is that too out of the way?

Thanks all for the great feedback!

With just a day and a half in Naxos you probably would want to find a hotel at St George beach. Its the town beach just a 15 minute stroll into Naxos town waterfront promenade. You will not be able to fully discover all of Naxos town on such a short visit.

You might prefer to extend your stay in Nafplio instead of trying to get an island experience. Nafplio feels like and island so make it your island experience. It has several nearby ancient sites including Mystras the last Byzantine city, Ancient Corinth the huge fortress at Acrocorinth and ancient Nemia which had sister games to Olympia and the stadium is still there. That is probably a better use of your time.

Some more images.
Nafplio https://www.flickr.com/photos/stanbr54/albums/72157632094108982
Nafplio 2024 https://www.flickr.com/photos/stanbr54/albums/72177720319228274
Corinth Area. https://www.flickr.com/photos/stanbr54/albums/72157711755443483

Would Hydra be a day trip or is that too out of the way?

As you already have 'island time' in your plans, a day trip to Hydra is probably not the best use of your limited time. Delphi or Olympia might be better options if you feel you need a 'day trip' to somewhere.