If your idea of a good vacation means being near the water, head to Chiringashima Island. No matter what you choose to do here, you're unlikely to tire of those pretty views.
You'll need to find your way to Ibusuki to reach this water-surrounded land mass. If you're eager for some sightseeing after you're done, why not stop by Saraku Sand Bath Hall? It's within reach of Chiringashima Island.