Here’s a good article by Big Island Guide on Kealakekua Bay which is a favorite snorkeling spot for Sea Paradise.
One of the most famous snorkeling and kayaking areas in the world lies about 12 miles south of Kailua-Kona in Kealakekua Bay. Best known for its historical significance as the first European landing site in Hawaii in 1779 as well as the site of interactions between the two cultures and the untimely death of English Explorer, Captain James Cook. A visit to Kealakekua Bay offers a bit of an educational experience as well as being an incredible location for water activities.
From Palemano Point to Cook Point, Kaealakekua Bay is the largest natural bay on the Big Island, it’s 315 acres, measure around 1.5 miles by 1 mile. Its waters were designated as a Marine Life Conservation District in 1969 because of its abundance and diversity of marine life. The snorkeling area around the monument is inaccessible by car, but you have several options to tour Kealakekua Bay: boat tour, guided kayak tour or a steep hike into this historical and protected area.
Kealakekua Bay is a protected marine area, with some of the best snorkeling on the Big Island. The reefs are amazing along the shore to the left and right of Captain Cook’s monument. The coral shelf begins in a couple feet of water right next to shore so be careful not to stand up or touch the coral. As you swim out away from shore there are varied depths leading to flourishing coral and marine life abundant in every direction. Past the rocky point, the water becomes very deep and it is exposed to rougher tide and channel currents; be aware of conditions in the bay and stay closer to the shoreline.
Along Kealakekua Bay reefs, you will often see schools of tropical fish, Hawaiian Green Sea turtles and large healthy coral. In the morning, you might even spot Hawaiian Spinner Dolphins “spinning” out of the oceans’ surface, enjoying its sunshine waters with their mothers close by guiding them along the way. Due to the calm water conditions, extensive coral reef, and flourishing marine life, Kealakekua Bay offers world-renowned diving and snorkeling opportunities with its crystal clear waters, mirror-like ocean conditions, and more fish and marine life than you’ll ever believe.