One of the most incredible dives you can do in the world,is located in Kona, Hawaii. The specific dive is with large manta rays, while they feed on plankton that are attracted to the underwater lights placed near the Kona Airport.
After boarding a vessel out of Honokohau Marina in Kailua-Kona, you will travel to one of several dive locations along the Kohala coastline, known for the evening dives with manta rays.
For this dive you will not need to be scuba certified, as you can snorkel and still get quite the show. However many of the tours do offer Scuba diving as well as Snuba diving.