There is a very nice beach park located at the end of Kai Ala Drive which serves as the main entrance to the Westin resort. The parking lot is large. There are bathroom and shower facilities. There is also a covered pavillion and barbecue grills. It's a popular spot for family gatherings.
The beach itself is lovely, although it does drop off quickly once you enter the water. The ocean is generally calm. From the southern part of the beach - a hike from the beach park - you can swim out to Black Rock where the snorkeling is excellent.