Body Glove Hawaii Cruises: 51 foot tour boat offering whale watching plus snorkel and dolphin sails, departing from Kailua Pier. Site includes contact and pricing information, plus pictures of the trips.
Captain Zodiac Raft Adventures: Zodiac raft trips from Honokohau Harbor to Kealakekua Bay for snorkeling. Site states these types of boats are the least likely to cause sea-sickness.
Sea Quest Rafting and Snorkeling Adventures: Six-person snorkel tours: pictures, itinerary, and contact details.