Don't worry about that tongue twister of an official name; everyone on the island calls this beach 'A Bay.' 'A-plus' is another way of putting it: this beach has easy access, salt-and-pepper sand and calm waters that are well suited to windsurfing. Classically beautiful, it's backed by hundreds of palm trees and makes for fantastic sunset viewing. Drinking water, showers and restrooms are available. To get here, turn left off Waikoloa Beach Dr opposite the Kings' Shops.
The Waikoloa Beach Marriott fronts the beach's north end, but ancient fishponds add a buffer zone between the two. In that area, there's decent snorkeling directly in front of the sluice gate, where you'll find coral formations, a variety of fish and possibly sea turtles. Remember that, by law, you must remain at least 50yd away from turtles in the water.
Archaeologists have found evidence of human habitation dating back more than 1000 years. A short footpath with interpretive plaques starts near the showers.