Board a usual wooden boat for a traditional caldera journey, prevent for swims, visit the volcano
https://dallasupsv853.swiftnestly.com/posts/santorini-day-tour-itinerary-a-perfect-one-day-plan-to-see-the-island-s-top-highlights-4
Board a normal picket boat for a vintage caldera travel, stop for swims, visit the volcano, and have fun with onboard stories and snacks.