Maho Bay
One of the big draws for Maho Bay is that it is easily accessible by car. The road runs right alongside the beach, so visitors can just park on the side of the road and immediately begin enjoying the calm, beautiful bay.
The water here is shallow and relatively calm, making it ideal for those that just want to relax, or with younger children. One caution though: there's not a lot in terms of amenities available at this beach. There are bathrooms on the western end of the beach, but they are locked and not available for use by the public. The restrooms are for use by guests that have attained a permit to use the pavilion on that end.
The calm, shallow waters make for easy snorkeling, although much of the bay may not offer a lot of excitement for the avid snorkeler. Turtles are reportedly still found throughout the bay. Also, along the southern edge of the bay there are some rocks and a small reef that should be decent for snorkelers.