Four nights: Santorini or Mykonos?

I'd choose Santorini for four nights built around a caldera-view room and long meals, and Mykonos when swimming and beach days are the main reason for the trip. Choose one island. With four nights, I would spend the middle of the holiday at the hotel or water rather than packing for another arrival.

The room and its surroundings matter more than a label such as romantic or lively. A hotel outside town can make either island feel secluded; an evening out depends on the journey home. I would choose the three afternoons I want first, then compare the room and transport that make those afternoons possible. A sunset photograph is not a complete hotel location.

I'd choose Santorini when you want to spend an afternoon on your own terrace, have a slow dinner and look out over the caldera without needing a new outing each day. The Greek National Tourism Organisation's Santorini guide distinguishes the settlements along the caldera rim from the island's volcanic beaches. A room facing the caldera and a room near a beach are different searches.

I would make the view part of the booked room category, then read the route from the vehicle drop-off to that particular room. Ask the hotel for the number of steps, porter arrangements and whether the same climb separates you from breakfast. I would settle those details before paying a nonrefundable rate when stairs or a stroller could change the stay. A description saying sea view cannot answer them.

I'd choose Mykonos for a stay where you want to swim, have lunch near the water and decide about town after returning to the room. Begin with one beach you would happily repeat, then compare hotels around that day. I would not choose a town-side room and assume that every beach afternoon will be equally simple.

The official Mykonos beach guide separates choices including Ornos, Platis Gialos, Psarou and Agios Ioannis. I would start around Ornos or Platis Gialos for a beach-led hotel search, then inspect the exact property entrance and the walk to the sand. If town dinners are the priority, I would reverse that search and budget for the beach journeys.

Do not let the island's party reputation make the room decision for you. The question is what happens outside your room, when it stops and how you get back. A hotel that suits a social couple can be the wrong address for a child's early bedtime, even when the photographs look peaceful.

I would pay for space and water you will actually use, rather than treat every pool photograph as the same room. Cavo Tagoo Santorini's room list makes that distinction concrete: its Junior Suite with Hot Tub lists 18 square metres indoors, while the Pool Suite lists 26 indoors and a private pool. Outdoor area is listed separately. A large terrace does not make the bedroom larger, and a hot tub is not a swimming pool.

I would compare Cavo Tagoo Santorini for a hotel-led stay, then settle the actual room access and pool terms with the property. A private pool label alone does not establish heating, privacy from neighboring terraces or suitability for children. For Mykonos, Cavo Tagoo's own site presents its pool and restaurant-led stay, including Meraki and nearby Zuma. I would consider that for afternoons at the hotel; I would separately establish the journey to the beach I intend to use.

In Santorini, I'd keep arrival afternoon for the room and an easy dinner. Use the first full day for a local village walk and a long lunch, the second for one outing chosen around your interests, and the third for the hotel and an evening you do not have to hurry. A wine visit or boat outing belongs on that middle day only if it is something you want, not an obligation to fill the itinerary.

In Mykonos, I'd settle in on arrival, use the first full day for the beach near the hotel and the second for town and a different dinner. Leave the third full day for another swim or a single prearranged outing. Four nights normally gives three full days between arrival and departure. I would protect one of those days from timed reservations, particularly when the hotel is a large part of the cost.

For four nights, I would not split. The move includes checking out, reaching the departure point, waiting, the crossing and reaching the next room. The time printed for a flight or ferry is only one part. A second hotel also leaves a gap when you may have bags but no room, which is a poor use of the shortest part of the holiday.

For a longer trip, I would consider both only when the two stays do different jobs: several nights for a caldera hotel, followed by enough beach days to settle into Mykonos. Match actual-date transport and cancellation terms before locking either hotel. I would avoid making a separate-ticket island departure the only connection protecting a long-haul flight home; leave room in the route for a disrupted transfer.

I would compare the flight or ferry arrival, the hotel entrance and the specific room together. Then reserve the room whose layout and arrival arrangements have been confirmed. Keep a late arrival simple: a transfer arranged to the right property and a dinner that does not depend on an optimistic landing time. Add outings after those pieces fit.

For dates outside a hotel's main operating period, establish the property's actual opening dates and the restaurants or pool facilities included for your stay. A summer photograph does not establish an October or spring service. I would choose the island only after the version of the hotel being sold for your dates is clear. The Greece planning hub keeps the island choice together; for another hotel-led coast, compare the Palma and Port de Sóller decision.