Most people arrive to Santorini via water and that should be the start of your experience in Santorini. Get outside and to the edge of the boat once Santorini comes into view and stay there for the entire ride in as you’ll most likely be sailing between the caldera and volcano, offering incredible views of both. The now mostly submerged volcano erupted thousands of years ago and the eruption was so powerful it resulted in most of the island falling into the ocean and producing the caldera, on which many of Santorini’s most picturesque towns are seated.
Fira is the main town in Santorini and will probably be the first you find during your one day in Santorini. Fira lacks a lot of the charm the other towns and villages of Santorini have and is a bit of a tourist trap so plan on getting out of there quickly.
While you may not have time to lie on the beach if you only have one day in Santorini, you should still visit them because the beaches there are pretty remarkable due to the volcanic ash. The Red Beach is my favorite. After a climb over some rocks (note it is a bit of a hike to get there from the town of Akrotiri so may not be ideal for some people) you descend upon a narrow piece of beach with red pebbles and a red and black rock backdrop cradling a little alcove of turquoise water. It’s a stunning sight.
Oia is built into the side of the cliff with some definite gravity defying buildings hugging the edge of the caldera. The precarious looking nature of the architecture results in some jaw-dropping views.
Watching the sunset from Oia is ideal. However, for some people who have ferries or cruise ships to catch shortly after it sets, getting back from Oia in time isn’t your best bet and can be risky if you have to rely on public transportation due to limited availability of taxis and local buses if your scooter or car has already needed to be returned. In that case, head to the north part of Fira and eat at one of the several restaurants situated along the caldera there that are perfect for dinner while you watch the sunset. Make a reservation or get there early in order to get a prime sunset viewing table. Have an excellent dinner and view.
If you need somewhere to lie your head while in Santorini, I have two options. The first is in Oia, because I love it there. The second is in Fira, and is a good option if you need somewhere to sleep before catching a ferry off the island the following day.