When visiting the Big Island many times a place called 'Two Step" is the recommended place to go snorkeling. I agree it is fun, wide open, full of fish and I love it myself. But, if I was new to snorkeling it could be a bit intimidating especially if the waves are fast that day. A great place for beginners and seasoned snorkelers too is Kahaluu Beach. It's much closer to Kailua-Kona town, has a lifeguard, rental equipment is available, and you can wade in instead of jumping in as you do at "Two Step". Usually there are volunteer interpreters there and actually there are more fish species to be seen because of the protected area there. I'm would take a guest to either place but I'd take a beginner definitely to Kahaluu Beach. I always see tons of fish there and sometimes turtles, too.
Snorkelling around this historic monument in the marine sanctuary of Kealakekua Bay is supposed to be among the best on the island. There certainly were a lot of colorful fish here. I've read there are spinner dolphins around, too, but we didn't see any the day we went. The monument marks the spot where explorer Captain Cook, the first European who happened upon the Hawaiian Islands, met his end in the late 1700's at the hands of islanders who had formerly thought him a god.
We took a sailboat tour here from Keahou, which was wonderfully relaxing, but you can also rent kayaks and paddle here on your own, or hike a rugged, unappealing trail in the sun for several miles (no roads come here). Kayakers are the only people allowed to dock and walk around on the land here - everyone else who arrives by boat has to stay in the water (or the place would probably be overrun). This little speck of land is actually owned by the British.
Kahalu'u beach is one of the big island's most popular snorkeling spots due to its easy access. You can snorkel right off the beach, and the place is very rich with tropical fish species and Honu (sea turtles).
You don't need expensive gear and you don't have to go far to experience the wonders under the ocean's surface. Heck, you don't even have to know how to swim. Just float on the top of the water (salt water very buoyant) and watch the world below. If you get tired and need a break, just stand up! Fantastic beaches close by and in town that are free and easy to get to.
I was able to snorkel at five spots around the island and by far the best was at Kahalu'u Beach. Get there early as you have the best visability in the morning, the fish are hungry, and the beach tends to be quite crowded later in the day.
On two separate dives I was able to see turtles, puffer fish, wrasses, lobster, parrotfish, and eel. Best spot is about 100 feet offshore near the center of the reef. Very cool.
The drawback is the beach. If you're with someone that doesn't swim, the beach is crowded, dirty and noisy and quite small. I would have been back more often if my wife had enjoyed the beach. My biggest surprise about the Kona area was the lack of those classic long sandy beaches. Just a few brief bits of sandy beach and the rest rough volcanic lava.
Snorkeling is what I enjoy doing when visiting the Hawaiian Islands. I was looking at the different local cruise companies I was immediately drawn to the Fair-Winds company. I recall using them for a snorkel cruise back in 1988 and I am glad that I chose them again. Aboard the Fair_wind a continental breakfast is served while cruising down the Kona coast to a sheltered embayment known as "Kealakekua Bay" where the memorial stands for Captain Cook who discovered the islands in the 1700's.
Once we arrived at the site we were instructed on snorkel techniques and advised to stay off the rocks and coral because these are protected waters and the reef is being destroyed by those who walk, sit or stand on it. If the reef dies then the fish in the area will starve and die. The Fair-Wind staff are all certified lifeguards and they took their posts both in the water as well as out on the fore and aft decks of the boat. There are a variety of floatation devices and they have a "viewing box" which floats on the water's surface and enables underwater viewing without putting your face in the water, this is great for kids!
After a good hour of snorkeling we returned to the boat, I like the fact that the ladder extends far out into the water making it quite easy for me to climb back aboard. The bar-b-q was going full steam and a delicious lunch of garden burgers and hamburgers were cooked by the captain. Pasta salad, fruit and chips were also a part of the fare offered.
One thing that impressed me, a gentleman ordered a beer and the staff politely asked his name and then wrote it down on a clipboard. The crew monitors alcohol consumption of all who imbibe and they keep a close watch on any and all persons who have consumed alcohol.
The cruise offers "Snuba" which gives you an experience similar to scuba diving only you go down 1 atmosphere (25 feet) and utilizing a regualtor which is attached to an oxygen line so you have no need to carry oxygen on your backs.
Kahalu'u Beach is a great place to snorkel. There is a family of turtles that live here and when I was snorkeling what I thought to be a big rock got up and swam. He was not afraid of me and I was able to take many pictures.
When you first get in the water it is cold, this is because of fresh springs which feed this little bay. Swim out about 100 feet and the water clears and becomes warm.
The water inside the reef is generally pretty calm but watch out during high surf when rip currents can occur.
Charter a sportfishing boat at the marina in Kona and cruise towards Kealakekua Bay (site of the Captain Cook monument) for snorkeling. Catch a 35 lb. dorado and eat it that night! Top ten "highlights of life".
There are numerous beaches along the dry side of the island (i.e. the west side) with really good snorkelling. I saw my first sea turtles here, along with plenty of colorful fish. We also happened to be here when the humpback whales were in the area (typically November through May), and saw several of them breaching. That was great - we even saw some right from the window of the beach house we rented.
Look But Don't Touch - the Big Island's sea turtles are making a comeback after being endangered. They're protected and it's illegal to touch or harass them.
At Kahalu'u Beach Park good snorkeling is just a short walk from the parking lot. You don't have to go far from shore to see loads of fish and a good chance at seeing some sea turtles.
At the far end of Kealakekua Bay is probably the best snorkeling in the state, with crystal clear water, a beautiful coral reef, and plenty of fish. The easiest way to get to this area is by renting the previously mentioned kayak and paddling across to the Captain Cook Monument.