One of our favorite places to watch the sunset (other than from our yard!) is Ke’ei Beach. The water is an incredible blue and is crystal clear. Some days it is difficult to get out of the water so we recommend jumping in for advanced swimmers only. Manini Beach is just around the corner from Ke’ei Beach and it has a nice entry and is a better spot to go if you are nervous or have children.
Here is a video so you can get an idea of the beauty of Ke’ei Beach. It is even better in person. Enjoy!