Why look beyond Santorini
The problem is geometric, not aesthetic. Almost every Santorini hotel worth booking sits on the caldera rim in Oia, Imerovigli or Fira, a strip a few kilometres long. Cruise arrivals, day trippers and hotel guests funnel into the same footpaths at the same hours, and the sunset crowd in Oia has become the most photographed queue in the Mediterranean.
Price follows that scarcity. A caldera view suite in high season costs multiples of an equivalent room on an island an hour away, and much of the premium buys the view rather than the room, the service or the food. On Milos and Paros the same money buys a larger room, a car and a week rather than three nights.
Santorini is a poor beach island. The volcanic beaches at Perissa and Kamari are dramatic but coarse, and the swimming is nothing like Milos, Crete or the Athens Riviera. For a trip built around water rather than photographs, it is the wrong island before you consider the crowds at all.
The Athens Riviera is the coastal strip running south from Athens through Glyfada and Vouliagmeni. You land, you drive twenty minutes, you are at the sea: no ferry, no island flight and no lost day at either end. The counterargument is that you are still on the edge of a capital of nearly four million people, with a motorway behind the bay.
Milos is volcanic like Santorini, but the geology went a different way: white rock shelves, sea caves, mining scars and coloured cliffs, with more than seventy beaches. Hotels are lodges and small hotels in the twenty to fifty room range. You need a hire car, and in August you need to have booked it months ahead.
Paros has quietly become the island that people who used to go to Mykonos now choose. Naoussa's harbour is the draw, a working fishing port with a dense grid of restaurants behind it. The trade off is August, when the road between Parikia and Naoussa becomes a queue. June and September are a different island entirely.
The Peloponnese is the outlier here because it is not an island at all. You drive from Athens, roughly two and a half hours to Porto Heli, and in exchange you get hotel grounds measured in hectares rather than metres.
Crete is the answer when the trip is a week or longer. Two international airports, a season that runs from April into late October, and 260 kilometres of island between Chania in the west and Ierapetra in the south. In late October, when the Cyclades have largely closed, the Cretan south coast is still swimmable.
How to choose. Three nights or fewer, stay on the Athens Riviera. A week of swimming and driving, choose Milos. Villages, food and beaches together, choose Paros. Anything longer than a week, or a trip in October, choose Crete. Two bases in two weeks is the right pace; three islands in ten days is the mistake I see most often.
One booking rule. In high season, book the ferry or the internal flight before the hotel.
